View Full Version : cantalevered deck
Chuck Kaatz
03-10-2012, 11:06 AM
This deck is sturdy and the cantalever stubs are solid.
Is there a code violation or would there be enough structural concern to recommend installing a ledger board.
BridgeMan
03-10-2012, 12:13 PM
The attachment of deck joists to existing cantilevers only meets Code if the local AHJ says it does. The IRC does not allow decks to be installed at cantilevers, unless they are free-standing (and therefore not really attached).
Suggesting that a conventional ledger be installed would not be particularly wise, as that implies you condone doing something not in compliance with the IRC. It would be better to recommend the AHJ be brought into the picture, who would either give their blessings to it (if they haven't already) or demand that some form of retrofit be performed.
Ken Rowe
03-10-2012, 12:40 PM
It's pretty much impossible to install proper flashing where the joists penetrate the siding. I would expect to see rot to the joists and sub-floor in the interior.
Jerry McCarthy
03-10-2012, 02:09 PM
Not good, disclaim and defer to structural engineer.
Kristi Silber
03-10-2012, 07:03 PM
A ledger board in this case wouldn't make sense. The joists are supported by the wall.
wayne soper
03-11-2012, 01:17 AM
they bastardized what was once a deck that attached to the floor joists through the block wall.
When the old wood rotted, they cut it off, attached smaller sized material and connected it with what appears to be ONE carriage bolt in each.
You always have to consider that during the open house festivities on moving in, a deck will be under heavy load with 30 to 40 people doing the macccarena on it.
Follw Jerry's advice and get a SE over to design repairs or rebuild.
Jerry Peck
03-11-2012, 08:19 AM
The solution at this time is to make that deck a supported deck and not a cantilevered deck, and have the structural engineer design that supported deck.
Any cantilevered deck a structural engineer comes up with for that would still be of a concern because how are they going to get back into the structure, unless that was a garage with an open ceiling. The structural engineer will likely go with a supported deck anyway.
Kristi Silber
03-11-2012, 10:11 AM
I agree it would be best to get a SE in. Hard to tell much based on what we can see and your description. If it's a deck (supported by ground), it's got far better chances than if it's a balcony, likewise if there's a large roof overhang above and a slight pitch to prevent the water infiltration Ken mentioned. I see two carriage bolts per joist.
Ken Amelin
03-11-2012, 10:51 AM
I wouldn't use that method of attachment if the deck is still cantilevered, but in my opinion this method of fastening the ends of the new joist to the structure would be acceptable provdied the wood tail pieces that rest within the block foundation are solid . I would also expect to see columns supporting the other end of the joists.
Garry Sorrells
03-11-2012, 11:00 AM
This deck is sturdy and the cantalever stubs are solid.
Is there a code violation or would there be enough structural concern to recommend installing a ledger board.
I would say yes to a code violation without knowing your local requirements.
It may be working for now, but think about how it is bolted together and where the shear forces are working.
The need for a SE or a decent contractor to advise on how to correct the structure depends on you location. From the way it looks a ledger board with bolts and hangers would seem a viable solution, as well as converting to an independent support to the ground with footers. Also, the materials for the span have to be correct.
Nick Ostrowski
03-11-2012, 11:33 AM
I think an SE is overkill as there are no hidden or unseen forces at work here. A competent general contractor or deck installation professional should be able to make the appropriate corrections.
Kristi Silber
03-11-2012, 01:10 PM
I would say yes to a code violation without knowing your local requirements.
It may be working for now, but think about how it is bolted together and where the shear forces are working.
The need for a SE or a decent contractor to advise on how to correct the structure depends on you location. From the way it looks a ledger board with bolts and hangers would seem a viable solution, as well as converting to an independent support to the ground with footers. Also, the materials for the span have to be correct.
I don't understand how a ledger board would work here - why it would be needed, or what kind of support it would add. The "cantilever stubs" are already well-supported at the point of the CMU wall (where a ledger board would go), it's the rest of the structure that is questionable. It would be relatively easy to improve the attachment of the deck joists to the stubs if necessary (are there any nails/screws on the side we can't see?).
Maybe it's not the case in general, but in my job, "deck" is defined as being supported at least partially by the ground (posts and footings, usually), while "balcony" is used for structures without direct ground support.
So, Chuck, is this a deck or balcony we're looking at? And how big? Is there much of a roof overhang above it? How old are house and deck/balcony? A photo showing more of the structure would be good.
Jerry Peck
03-11-2012, 01:19 PM
Maybe it's not the case in general, but in my job, "deck" is defined as being supported at least partially by the ground (posts and footings, usually), while "balcony" is used for structures without direct ground support.
Basically correct, but I did not want to throw in another twist into the discussion, so I just suggested that it be a "supported deck" to clarify that the ends, or at least at some other point out from the wall, be supported and that it is not left cantilevered.
BALCONY, EXTERIOR. An exterior floor projecting from and supported by a structure without additional independent supports.
DECK. An exterior floor system supported on at least two opposing sides by an adjoining structure and/or posts, piers, or other independent supports.
BridgeMan
03-11-2012, 01:28 PM
I think an SE is overkill as there are no hidden or unseen forces at work here. A competent general contractor or . . .
Sounds good on paper, but should the deck collapse after being filled with many tons of people the owners have invited over for the grand house warming-party, you know the question that will be raised--"Why didn't our home inspector tell us to have an engineer take a look at it, when he knew (or should have known) it doesn't meet Code?"
Competent general contractors are not allowed to practice engineering, and asking them to do so is risky, if not illegal.
Kristi Silber
03-11-2012, 03:41 PM
Basically correct, but I did not want to throw in another twist into the discussion, so I just suggested that it be a "supported deck" to clarify that the ends, or at least at some other point out from the wall, be supported and that it is not left cantilevered.
I don't think it's throwing another twist into the discussion to introduce basic definitions so we can all communicate. It seems like some people are assuming this is a balcony (e.g. Jerry M's diagram), when Chuck called it a deck. There's not much point in saying anything about it without knowing which it is. For all we know, the weight is all resting on posts and the stubs are for stability and attachment.
Jerry Peck
03-11-2012, 03:52 PM
It seems like some people are assuming this is a balcony (e.g. Jerry M's diagram), when Chuck called it a deck.
I think most of us presumed it was a balcony when Chuck said:
This deck is sturdy and the cantalever
If it was a deck, it would not be cantilevered from the wall ... correct? ;)
Nick Ostrowski
03-11-2012, 04:06 PM
Sounds good on paper, but should the deck collapse after being filled with many tons of people the owners have invited over for the grand house warming-party, you know the question that will be raised--"Why didn't our home inspector tell us to have an engineer take a look at it, when he knew (or should have known) it doesn't meet Code?"
Competent general contractors are not allowed to practice engineering, and asking them to do so is risky, if not illegal.
I don't see how this is an engineering issue, or how not being code compliant makes it an engineering issue. The deck was installed incorrectly. Get a professional in that field of expertise to work on it. They will either make the appropriate repairs or recommend tearing it down and starting from scratch.
Jerry McCarthy
03-11-2012, 05:25 PM
There are those that would refer to what was originally posted as a "balcony deck." Ah.... semantics? :D
Ken Amelin
03-11-2012, 07:29 PM
[quote=Jerry Peck]Re: cantalevered deck
Quote:
Originally Posted by Kristi Silberhttp://www.inspectionnews.net/home_inspection/images/ca_evo/buttons/viewpost.gif (http://www.inspectionnews.net/home_inspection/exterior-systems-home-inspection-commercial-inspection/29606-cantalevered-deck.html#post192338)
It seems like some people are assuming this is a balcony (e.g. Jerry M's diagram), when Chuck called it a deck.
I think most of us presumed it was a balcony when Chuck said:
Quote:
Originally Posted by Chuck Kaatzhttp://www.inspectionnews.net/home_inspection/images/ca_evo/buttons/viewpost.gif (http://www.inspectionnews.net/home_inspection/exterior-systems-home-inspection-commercial-inspection/29606-cantalevered-deck.html#post192253)
This deck is sturdy and the cantalever
If it was a deck, it would not be cantilevered from the wall ... correct? ;)[/quote)
Jerry, your reference to Chuck's quote was misleading and could be taken out of context.
Chuck originally quoted "This deck is sturdy and the CANTILEVERED STUBS are solid."
With that said, it could very well be a deck and not a balcony.
Jerry Peck
03-11-2012, 07:44 PM
Jerry, your reference to Chuck's quote was misleading and could be taken out of context.
Chuck originally quoted "This deck is sturdy and the CANTILEVERED STUBS are solid."
With that said, it could very well be a deck and not a balcony.
Ken,
I doubt it was misleading to anyone.
"With that said, it could very well be a deck and not a balcony."
It *could* have been a deck, but I think you were misleading when you said "could very well be" because I suspect that, while it 'could' have been a deck, that we all presumed it was a cantilevered balcony because there would be absolutely no reason to cantilever out for a "deck", and, if they were cantilevered out for a deck, then those stubs would not have been "cantilevered", would they?
You are talking words and semantics, so I am too.
Typically: a projecting beam or member supported at only one end
Billy Stephens
03-11-2012, 07:57 PM
[quote=Jerry Peck]Re: cantalevered deck
Quote:
Originally Posted by Kristi Silberhttp://www.inspectionnews.net/home_inspection/images/ca_evo/buttons/viewpost.gif (http://www.inspectionnews.net/home_inspection/exterior-systems-home-inspection-commercial-inspection/29606-cantalevered-deck.html#post192338)
It seems like some people are assuming this is a balcony (e.g. Jerry M's diagram), when Chuck called it a deck.
I think most of us presumed it was a balcony when Chuck said:
Quote:
Originally Posted by Chuck Kaatzhttp://www.inspectionnews.net/home_inspection/images/ca_evo/buttons/viewpost.gif (http://www.inspectionnews.net/home_inspection/exterior-systems-home-inspection-commercial-inspection/29606-cantalevered-deck.html#post192253)
This deck is sturdy and the cantalever
If it was a deck, it would not be cantilevered from the wall ... correct? ;)[/quote)
Jerry, your reference to Chuck's quote was misleading and could be taken out of context.
Chuck originally quoted "This deck is sturdy and the CANTILEVERED STUBS are solid."
With that said, it could very well be a deck and not a balcony.
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Misleading And Out Of Context ? :eek:
Say It Ain't So!:rolleyes:
*fwi they are called Avatars
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Kristi Silber
03-11-2012, 08:30 PM
I think most of us presumed it was a balcony when Chuck said:
This deck is sturdy and the cantalever
If it was a deck, it would not be cantilevered from the wall ... correct? ;)
When he said, "...and the cantalever stubs are solid," I took that to mean he was talking about a specific part - the bits sticking out of the wall. But I wasn't sure myself.
that we all presumed it was a cantilevered balcony because there would be absolutely no reason to cantilever out for a "deck", and, if they were cantilevered out for a deck, then those stubs would not have been "cantilevered", would they?
First, "we all presumed..." isn't true.
If this thing was designed as a cantilevered balcony when the house was built, it would not have the transition it does; obviously, the "deck" is younger than the cantilever stubs. That means we can't depend on "reason" for the way the deck/balcony is now structured because we don't know how it was originally. For all we know, it's a balcony and not a cantilever.
If it is a true cantilever balcony, and those two carriage bolts are the only things supporting it, that would be crazy. Screwing the decking down properly to the "stubs" and the joists would add some stability to the joint. Add a steel bracket of some sort (or modified joist hanger)over the top of the joists at the wall end, another under the opposite end, and you're good to go! :D
This does not address the water infiltration issue. :confused:
****NOTE: do not mistake my off-the-cuff gut feelings for advice! ;)
Garry Sorrells
03-12-2012, 05:37 AM
The original post said nothing about a cantilevered balcony.
A deck was added to the house using the existing cantilevered 2x from original structure (balcony most likely), a time saver but bad construction concept.
Should have cut off the joist flush with structure and lagged/bolted a ledger onto the house and used hangers.
Rod Corwin
03-12-2012, 07:33 AM
The original post said nothing about a cantilevered balcony.
A deck was added to the house using the existing cantilevered 2x from original structure (balcony most likely), a time saver but bad construction concept.
Should have cut off the joist flush with structure and lagged/bolted a ledger onto the house and used hangers.
^^^Exactly ^^^ KISS :)
Michael Avis
03-12-2012, 09:15 AM
Whether it is a balcony or a deck, cantilevered or supported is somewhat off point. The connection between the new and existing structure has to resist the forces it will be supporting. Period. The live and dead loads on the floor against the house are what they are.
What matters, based on a tiny photo, is the quality of the original lumber you are attaching to, its support and the quality of the connection you are making between new and old wood. I don't see any thru-bolts so if this connection is simply nailed it may not be adequate to the task as Bridge Man has already said.
What we don't want here is a moment connection that overpowers the nails either in shear stresses or pull-out. If there were a big party and the deck/balcony was crammed with human beings, I would be hanging out inside.
This is absolutely a condition that would benefit from an SE. I would write it up as suspect and recommend the attention of an architect or engineer.
Billy Stephens
03-12-2012, 09:25 AM
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I see two carriage bolts per joist.
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I don't see any thru-bolts .
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Look Again. ;)
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Chuck Kaatz
03-12-2012, 09:54 AM
The new deck uses 2 post for support, the cantalever stubs are used for support at the house. If the stubs are solid and the joists are sistered properly I dont see a problem. This deck has enough issues to call in a structural engineer and the city inspector.
Billy Stephens
03-12-2012, 10:00 AM
I think most of us presumed it was a balcony when Chuck said:
If it was a deck, it would not be cantilevered from the wall ... correct? ;)
The new deck uses 2 post for support, the cantalever stubs are used for support at the house. If the stubs are solid and the joists are sistered properly I dont see a problem. This deck has enough issues to call in a structural engineer and the city inspector.
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Wow a Deck.
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Rod Corwin
03-12-2012, 10:12 AM
Common sense tells me this can't be a balcony. There would not be enough support by just bolting to the sides of those through the wall joist's, which may or may not be a part of the interior floor joist's, they may be just stubs encased in the wall. Secondly they don't appear to be treated "stubs" giving a red flag to life expectancy before degradation to the point of shear. Should of cut stubs off and used a ledger board with brackets. In order to fix this without tearing deck out they should lag bolt treated lumber between each joist to wall and L bracket both sides of joist or put a ledger board under the joists whole length and bracket to the joists to tie it all together.
Billy Stephens
03-12-2012, 10:15 AM
Common sense tells me this can't be a balcony. .
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Common Sense you Say ? :D
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Barry newDelman
03-12-2012, 10:33 AM
For whatever its worth. it does not make any difference if you cak it a deck or a balcony. if its a cantilevered structure it shold be enginerred by a Strcuturl engkineer or an architect who is qualified. the rule of thumb shown is correct 2x the cantlever back into the building and sistered to an adjacent joist.
the jost size must be sized to take the max superimposed load at teh outer plane. check with applicable codes, (remem ber what happend in Chicago a few years back). Chicago now requires 100 #/sf live load
simple soulution install diagonal bracing from wall to a min of 1/3rd of the cantilver lever.
Jerry McCarthy
03-12-2012, 10:35 AM
Now this is a balcony deck......................... right?
Nick Ostrowski
03-12-2012, 10:36 AM
The original post said nothing about a cantilevered balcony.
A deck was added to the house using the existing cantilevered 2x from original structure (balcony most likely), a time saver but bad construction concept.
Should have cut off the joist flush with structure and lagged/bolted a ledger onto the house and used hangers.
What Gary said. Don't need a structural engineer for this.
Rod Corwin
03-12-2012, 11:10 AM
Now this is a balcony deck......................... right?
I stand semi corrected. That is a balcony. A balcony may or may not have front supports running to the ground. Researching I have found out that a 2nd story deck would have stairs to the ground. No access to ground would make it a balcony. Hence the original pic does not give enough info to determine if it is a deck or balcony. Either way the fact is that the pic shows that it is not the correct way of doing it. I would call it out in my report.
Door Guy
03-12-2012, 11:43 AM
Has anyone considered the extra load put on the cantilever. By extending those joist outward and adding load, what about uplift on the reverse end? Thoughts?
Michael Avis
03-12-2012, 12:13 PM
I see no thru-bolts, carriage bolts or anything. I see a little circle on one joist that could be a knot for all I can tell. Maybe your eyes are better than mine. I think my original comments about the nature of the mechanical connection hold true.
Kristi Silber
03-12-2012, 12:26 PM
Now this is a balcony deck......................... right?
What the heck is a balcony deck?
A balcony may or may not have front supports running to the ground. Researching I have found out that a 2nd story deck would have stairs to the ground. No access to ground would make it a balcony.
Rod, where did you find this definition?
According to the definition Jerry P got somewhere (which agrees with what I learned), Jerry M's example would be a deck. It's supported by the ground. A balcony is entirely supported by the structure to which it is attached, a deck is not. I know this is semantics, and there are obviously different definitions, but these seem pretty helpful and structurally meaningful.
Whether it is a balcony or a deck, cantilevered or supported is somewhat off point. The connection between the new and existing structure has to resist the forces it will be supporting.
But whether it's cantilevered or supported will determine the types of forces that must be accounted for. If this were a balcony the current way of tying it to the house would be much better than using a ledger board. As a deck, it doesn't make much difference, but I still don't see the benefit of a ledger board in this case except possibly for reasons of moisture control.
Kristi Silber
03-12-2012, 12:33 PM
I see no thru-bolts, carriage bolts or anything.
There are two bolts (presumably) with washers on each cantilever stub.
Has anyone considered the extra load put on the cantilever. By extending those joist outward and adding load, what about uplift on the reverse end? Thoughts?
It's not a cantilever, but if it were it would be impossible to judge without more info anyway. There are too many unknowns here!
Rod Corwin
03-12-2012, 01:14 PM
[quote=Kristi Silber;192472]What the heck is a balcony deck?
Rod, where did you find this definition?
According to the definition Jerry P got somewhere (which agrees with what I learned), Jerry M's example would be a deck. It's supported by the ground. A balcony is entirely supported by the structure to which it is attached, a deck is not. I know this is semantics, and there are obviously different definitions, but these seem pretty helpful and structurally meaningful.
NACHI
Balconies
http://www.nachi.org/images09/balcony.jpg
A balcony is a platform that protrudes from the wall of an upper floor of a building and is enclosed by a railing. Balconies are often highly decorative, especially in wealthy or scenic areas. They are not designed as social areas but, rather, add an outdoor ambiance to the indoors.
Balcony Facts:
In William Shakespeare’s Romeo and Juliet, Juliet famously courted Romeo from her balcony. The small balcony design typically associated with that scene is often referred to as a “Juliet balcony.”
Balconies can be large enough to resemble decks, but they do not provide access to the ground.
"Balcony" originates from the Italian word balcone, which means “large window.”
Balconies can be made from wood, iron, stone, and many other masonry materials.
From Exterior Design Features - InterNACHI (http://www.nachi.org/exterior-design-features.htm#ixzz1ow3hOGgD) Exterior Design Features - InterNACHI (http://www.nachi.org/exterior-design-features.htm#ixzz1ow3hOGgD)
Also found this on a architecture site: A balcony is a platform built out from and only accessible from an upper story, room or corridor.
BridgeMan
03-12-2012, 02:31 PM
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Deck or Balcony?
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Or to put it in perspective, "Is she skinny, thin or svelte?"
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Kristi Silber
03-12-2012, 02:51 PM
Neither of those definitions make it sound like there are supports to the ground.
Ironically, the reason I brought up balcony vs. deck was to simplify the conversation, but it's just become another issue. A platform that is supported on one side is going to have different structural and physical properties than one that is also supported on the opposite corners, and those properties could determine whether the current structure is acceptible or not. Since the means of support are the pertinent features here, can't we just agree to use those in the definition for now?
I guess it's a little late in the discussion for that. Oh well, call it whatever, don't make no nevermind to me.:p
Jerry Peck
03-12-2012, 05:18 PM
I think most of us presumed it was a balcony when Chuck said:
First, "we all presumed..." isn't true.
Ummmm ... Kristi, when you make people think you are quoting someone you should at least actually quote them and not make it up.
And the above is a good example of what Ken was talking about with 'out of context'.
Re-read what I posted, I quoted it above, and here:
"I think most of us presumed it was a balcony when Chuck said:"
You tried to make others believe that I said "we all presumed..." - see the difference between what I actually said and what you made up?.
Jerry Peck
03-12-2012, 05:35 PM
The original post said nothing about a cantilevered balcony.
Garry,
Read the title to the thread ... "cantalevered deck".
That says it right there, that is what sets the stage for what follows.
Jerry Peck
03-12-2012, 05:39 PM
According to the definition Jerry P got somewhere ...
Kristi,
Those definitions are from the IRC.
Jerry Peck
03-12-2012, 05:41 PM
The new deck uses 2 post for support, the cantalever stubs are used for support at the house.
Chuck,
Thank you for clarifying what that was - it is a deck now.
It may originally have been a cantilevered balcony, but that we do not know, unless you found evidence that there were originally posts at the outer end.
Kristi Silber
03-12-2012, 05:52 PM
Ken,
I doubt it was misleading to anyone.
"With that said, it could very well be a deck and not a balcony."
It *could* have been a deck, but I think you were misleading when you said "could very well be" because I suspect that, while it 'could' have been a deck, that we all presumed it was a cantilevered balcony because there would be absolutely no reason to cantilever out for a "deck", and, if they were cantilevered out for a deck, then those stubs would not have been "cantilevered", would they?
You are talking words and semantics, so I am too.
Typically: a projecting beam or member supported at only one end
Direct quote, Jerry. You were looking at the wrong one.
Please don't accuse me of trying to mislead people. You should know me better than that.
Jerry Peck
03-12-2012, 06:39 PM
Direct quote, Jerry. You were looking at the wrong one.
Please don't accuse me of trying to mislead people. You should know me better than that.
I thought I did know you better than that and searched for where I said that "all" thing and could not find it ... oops ... sorry ... I did say "all" there without the qualifier ... I try to avoid using "all", "never", etc., without a qualifier with it - I missed using the qualifier and I missed finding that when I looked for it ... even after looking through my posts several times trying to find that "all" ... not good - I must be slipping ... again, sorry. :o
Jerry McCarthy
03-12-2012, 06:51 PM
Balcony & Deck – the difference per 2007 CA Bldg. Code 1602A.1.
Balcony Exterior: An exterior floor projecting from and supported by a structure without additional independent support.
Deck: An exterior floor supported on at least two opposing sides by an adjacent structure, and/ or posts, piers or other independent supports.
BridgeMan
03-12-2012, 08:23 PM
Balcony & Deck – the difference per 2007 CA Bldg. Code 1602A.1.
Balcony Exterior: An exterior floor projecting from and supported by a structure without additional independent support.
Deck: An exterior floor supported on at least two opposing sides by an adjacent structure, and/ or posts, piers or other independent supports.
That spells things out quite clearly, for all of us who have been confused for the last several days here. Trouble is, that's a California code definition, and probably not applicable in the O.P.'s locale (MN).
Jerry Peck
03-12-2012, 08:26 PM
Balcony & Deck – the difference per 2007 CA Bldg. Code 1602A.1.
Balcony Exterior: An exterior floor projecting from and supported by a structure without additional independent support.
Deck: An exterior floor supported on at least two opposing sides by an adjacent structure, and/ or posts, piers or other independent supports.
Kristi,
Those definitions are from the IRC.
BALCONY, EXTERIOR. An exterior floor projecting from and supported by a structure without additional independent supports.
DECK. An exterior floor system supported on at least two opposing sides by an adjoining structure and/or posts, piers, or other independent supports.
California and the IRC as the same.
Ken Rowe
03-12-2012, 08:38 PM
I use common sense definitions:
Deck; has stairs
Balcony; doesn't have stairs
Patio; a deck less than 30 inches off the ground, may or may not have stairs
Kristi Silber
03-12-2012, 09:30 PM
I use common sense definitions:
Deck; has stairs
Balcony; doesn't have stairs
Patio; a deck less than 30 inches off the ground, may or may not have stairs
That may be a nice simple way of looking at it, but it's structurally not meaningful, and "common sense" doesn't have anything to do with it. I could just as well say the common sense distinction is balconies have solid floors and decks have planks with cracks between them. Maybe it makes sense to me, but there's nothing intuitive about it.
Ken Rowe
03-12-2012, 10:08 PM
That may be a nice simple way of looking at it, but it's structurally not meaningful, and "common sense" doesn't have anything to do with it.
Correct, it's not structurally meaningful, but common sense has everything to do with it. I do some inspections for structural engineers, but most of my clients are not in the building trades at all, so I write the reports so they understand what I'm talking about.
That's why I use the terms sub panel and electrical outlet, for example. Not technically correct, but the general public understands them. Kind of like calling all facial tissue Kleenex or an automobile a car.
Garry Sorrells
03-13-2012, 07:03 AM
Sorry Jerry, I took the OP as possibly just a mater of giving it a title and direction of intent of question.
How ever the OP chose to word the question and description of what was in the picture, the presumed direction was toward the attachment of the but ends of the wood in the picture. The description may have been better but I got the idea of what was going on. Not everyone can nor will give you a textbook definitive description in either the posting title or the question. Sometime close is good enough.
In my silly world of construction technique and practices in my little corner of the world.
If the picture was of a balcony, by any definition, it would be wrong.
If the picture was of a deck, by any definition, it would be wrong.
If the picture was of a bunch of lumber nailed and bolted together, it would be wrong.
The fact that two bolts and three nails hold the wood to the wall and support the load is poor by design and not meet code. What the rest of the structure was not in the question.
Sometime in the process we just do not look at the what is right in front of us. I do not think that Chuck's OP was attempting to make it into a trick question, looking for all the possible nuances of the potential what if scenario.
Kristi,
From my point of view it is about what is supporting the deck/balcony at the wall.
The bolts will not allow, if protruding lumber is attached back into house, to pull away from the main structure.
The issue then is the support is the deck/balcony/platform at the wall. By the force directed at the bolts in the lower portion of the 2x, what you see is a potential for the 2x to fracture the larger 2x in the lower third. Think of it as if the cantilevered 2x were notched and the deck was resting on the cantilevered section. How much of the cantilevered 2x would actually be the supporting the deck?
Garry Sorrells
03-13-2012, 07:10 AM
I use common sense definitions:
Deck; has stairs
Balcony; doesn't have stairs
Patio; a deck less than 30 inches off the ground, may or may not have stairs
So what would you call a cantilevered balcony with no vertical support that has stairs attached to it? Balconized Deck? Balcodeck?
Jerry McCarthy
03-13-2012, 09:04 AM
How about a porch? :D
Rod Corwin
03-13-2012, 09:49 AM
So what would you call a cantilevered balcony with no vertical support that has stairs attached to it? Balconized Deck? Balcodeck?
I vote for balcodeck. :D
BridgeMan
03-13-2012, 09:54 AM
Any wagers as to how long it takes to reach 100 posts on this dying horse?
Come on already, it's dead.
John Kogel
03-13-2012, 05:35 PM
So what would you call a cantilevered balcony with no vertical support that has stairs attached to it? That would be a fire escape. :D
That thing in the pic is a deck. No way it would be supported by those puny fasteners and those stubs alone.
When I see a mess like that, I wonder about the decks or balconies that have soffit covers nailed under them, with all the ugly work concealed by a nice white cover. See that a lot here..
Kristi Silber
03-13-2012, 06:53 PM
Kristi,
From my point of view it is about what is supporting the deck/balcony at the wall.
The bolts will not allow, if protruding lumber is attached back into house, to pull away from the main structure.
The issue then is the support is the deck/balcony/platform at the wall. By the force directed at the bolts in the lower portion of the 2x, what you see is a potential for the 2x to fracture the larger 2x in the lower third. Think of it as if the cantilevered 2x were notched and the deck was resting on the cantilevered section. How much of the cantilevered 2x would actually be the supporting the deck?
It's not the same as the cantilevered 2X being notched since there's sound wood there. Two small holes don't weaken the structure of the wood that much, and even the wood above the holes will provide some support. So will the decking tie the 2X6s to the 2X8s. Even if that bit were notched, it would take a lot of weight (or rotten wood) to break those. Because it's a deck, the force is straight down, not pivoting, and half the weight is on the posts (if there are only two, it can't be a very big deck). The weight along the wall is shared by multiple 2X8s.
Unless this is a large deck, the only real issue I see is moisture management to prevent water from getting in the wall - and that may not be a problem. If not, keep it like it is. If it needs reinforcement, add steel brackets. Cutting these things off and installing a ledger board makes no sense to me.
In the end it's impossible to say whether it's adequate, though, because we don't know the size of the deck.
...............
"Deckony"?
Jerry McCarthy
03-13-2012, 07:00 PM
Kristi, in all due respect you could not be more wrong!
Be it a deck or be it a balcony, it desperately needs an evaluation by an SE and any prudent home inspector would say so in their report. That is exactly the type of work that employs folks like me if not properly disclaimed and deferred.
Billy Stephens
03-13-2012, 07:10 PM
It's not the same as the cantilevered 2X being notched since there's sound wood there. Two small holes don't weaken the structure of the wood that much, and even the wood above the holes will provide some support. So will the decking tie the 2X6s to the 2X8s. Even if that bit were notched, it would take a lot of weight (or rotten wood) to break those. Because it's a deck, the force is straight down, not pivoting, and half the weight is on the posts (if there are only two, it can't be a very big deck). The weight along the wall is shared by multiple 2X8s.
Unless this is a large deck, the only real issue I see is moisture management to prevent water from getting in the wall - and that may not be a problem. If not, keep it like it is. If it needs reinforcement, add steel brackets. Cutting these things off and installing a ledger board makes no sense to me.
In the end it's impossible to say whether it's adequate, though, because we don't know the size of the deck.
...............
"Deckony"?
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Regardless of the Shown Deck Size ( abet the Larger the more problematic ) sheer strength of two bolts is insufficient to carry the probable live loads,
* the Deck joist are not fully clamped together as noted by the shown gap and even if they were still not sufficient or allowed to support the Structure.
** Bolt strengths (http://www.derose.net/steve/resources/engtables/bolts.html)
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Kristi Silber
03-13-2012, 09:02 PM
Kristi, in all due respect you could not be more wrong!
Be it a deck or be it a balcony, it desperately needs an evaluation by an SE and any prudent home inspector would say so in their report. That is exactly the type of work that employs folks like me if not properly disclaimed and deferred.
I should have been clear that I wasn't speaking from the standpoint of an HI, I was addressing Garry's comments about the structural aspects visible in the photos. Yes, I agree, it would be prudent for an HI to call in an SE, it often is to CYA.
What part exactly do you think was wrong?
Ken Rowe
03-13-2012, 10:22 PM
So what would you call a cantilevered balcony with no vertical support that has stairs attached to it? Balconized Deck? Balcodeck?
I'd call it wrong. Never seen one, have you?
Garry Sorrells
03-14-2012, 05:11 AM
Doing my part to get to 100 posts....
Kristi,
The point of my description to you was to look at the forces acting on the lumber and connection points. Guess I failed. Sorry. Every jurisdiction has its own codes. As a test take the picture to your local office and get their official opinion on the method of connection. Would love to hear the outcome. Also, most permit offices have a handout for deck construction requirements see if your permit office has one. Might ask if adding a second set of bolts at top might meet their standards.
I will give you another task.
Lets move this to the interior of a home.
Would this be acceptable for splicing a floor joist?
BridgeMan
03-14-2012, 09:09 AM
Doing my part to get to 100 posts....
Lets move this to the interior of a home.
Would this be acceptable for splicing a floor joist?
That all depends on whether it would be considered an interior balcony joist splice or an interior deck joist splice. We need to resolve that issue first, gang.
Enough of this procrastination.
Jerry McCarthy
03-14-2012, 09:34 AM
Without proper ground support it's an accident waiting to happen.
However, it that balcony, if it is one, would make a large diving board until the Sumo Dive team arrived. :(
Garry Sorrells
03-14-2012, 11:10 AM
That all depends on whether it would be considered an interior balcony joist splice or an interior deck joist splice. We need to resolve that issue first, gang.
Enough of this procrastination.
Balcodeck joist splice?
Kristi Silber
03-14-2012, 11:11 AM
Chuck said in post #27 that it's a deck, with two support posts.
Kristi,
The point of my description to you was to look at the forces acting on the lumber and connection points. Guess I failed. Sorry. Every jurisdiction has its own codes. As a test take the picture to your local office and get their official opinion on the method of connection. Would love to hear the outcome. Also, most permit offices have a handout for deck construction requirements see if your permit office has one. Might ask if adding a second set of bolts at top might meet their standards.
I will give you another task.
Lets move this to the interior of a home.
Would this be acceptable for splicing a floor joist?
You didn't fail, Garry, but I've been looking at the attachment and the forces on it the whole time, and I respectfully disagree with your analogy implying that having two bolts through the wood weakens it as much as a notch would.
I'm trying to stay away from blanket statements saying it's acceptible or not because we don't know all the info. Likewise it's impossible to say whether it would be an acceptible way of splicing an indoor floor joist without knowing any of the particulars. Please also notice I added that the joint could be reinforced if necessary.
I don't know if it's code, that's not what I'm addressing.
All I'm really saying is that from a structural standpoint it may not be necessary to cut the stubs flush (or recessed), somehow seal them from moisture penetration, put a ledger board up, cut the 2X6s to the right length (hopefully they reach that far) and install joist hangers. There could be easier solutions.
None of us can be certain of anything, that would take bringing in a SE.
Garry Sorrells
03-14-2012, 11:18 AM
Kristi,
"...You didn't fail, Garry, but I've been looking at the attachment and the forces on it the whole time, and I respectfully disagree with your analogy implying that having two bolts through the wood weakens it as much as a notch would. ..."
Not the point, it is that the loads are being concentrated on the bolts as if the wood above the bolts was notched and the deck joist was sitting on a notch ending at the bolt location.
Billy Stephens
03-14-2012, 11:22 AM
Chuck said in post #27 that it's a deck, with two support posts.
You didn't fail, Garry, but I've been looking at the attachment and the forces on it the whole time, and I respectfully disagree with your analogy implying that having two bolts through the wood weakens it as much as a notch would.
I'm trying to stay away from blanket statements saying it's acceptible or not because we don't know all the info. Likewise it's impossible to say whether it would be an acceptible way of splicing an indoor floor joist without knowing any of the particulars. Please also notice I added that the joint could be reinforced if necessary.
I don't know if it's code, that's not what I'm addressing.
All I'm really saying is that from a structural standpoint it may not be necessary to cut the stubs flush (or recessed), somehow seal them from moisture penetration, put a ledger board up, cut the 2X6s to the right length (hopefully they reach that far) and install joist hangers. There could be easier solutions.
None of us can be certain of anything, that would take bringing in a SE.
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That's the Only Thing We can be Certain of.
* HI's should not write the remedy nor do the correction.
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Kristi Silber
03-14-2012, 01:56 PM
Hmmm, Garry, I think I do understand you. My point is that notching is not like anything going on here. It's not a good analogy. Sorry, but I just can't see it.
I wonder if the decking is screwed or nailed.
BridgeMan
03-14-2012, 03:44 PM
Now that's got me thinking--I wonder if the deck planks are stained or painted?
Billy Stephens
03-14-2012, 05:54 PM
Any wagers as to how long it takes to reach 100 posts on this dying horse
Come on already, it's dead.
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Now that's got me thinking--I wonder if the deck planks are stained or painted?
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Now That's Just Stacking "The Deck!" :D
Everybody knows Painted Joists are Stronger just think about all those Microns of Paint Helping to supporting a Dozen People, Barbeque Grill, DJ Equipment, Ice Chests, Lawn Furniture, Table, Chairs, Baby Carriages Assorted Food and Beverages all Swaying to the Music on Two Big Box Carriage Bolts. :eek:
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Jerry Peck
03-14-2012, 05:57 PM
So what would you call a cantilevered balcony with no vertical support that has stairs attached to it? Balconized Deck? Balcodeck?
If the balcony is holding up the top of the stair, it is still a balcony.
If the stair is a structure which is holding up that end of the balcony, then it is a deck and not a balcony.
I have seen one ... one ... and the stairs were attached to the balcony and the balcony was holding up that end of the stair. It was a reinforced concrete stair which was riser-tread-riser-tread-etc. all the way to the top. The architect had not even designed a guard rail or handrail for the stairs. The owner eventually agreed that it was enough of a hazard for tipsy friends the he finally over rulled the architect and had guard rails and handrails installed. I've tried to find my photo of it, but I have not been successful yet.
Billy Stephens
03-14-2012, 06:18 PM
If the balcony is holding up the top of the stair, it is still a balcony.
If the stair is a structure which is holding up that end of the balcony, then it is a deck and not a balcony.
I have seen one ... one ... and the stairs were attached to the balcony and the balcony was holding up that end of the stair. It was a reinforced concrete stair which was riser-tread-riser-tread-etc. all the way to the top. The architect had not even designed a guard rail or handrail for the stairs. The owner eventually agreed that it was enough of a hazard for tipsy friends the he finally over rulled the architect and had guard rails and handrails installed. I've tried to find my photo of it, but I have not been successful yet.
.......
Jerry Peck
03-14-2012, 06:49 PM
I still can't find the photo, so I drew this up to offer a visual as to what it looked like - in a word: weird, then scary.
Garry Sorrells
03-15-2012, 02:47 AM
Now there is a design marvel. A floating deck. I like it. Is that you Jerry on the stairs? Looks like you may have lost a little weight. Would be great for those scenic overlooks along highways. Does it come in choice of colors?
What is it called? A Stairodeck?
Just for you BridgeMan. A thread that just keeps on giving.............
bob smit
03-15-2012, 09:47 PM
I forgot what I was going to post now......:confused:
Something about a cantilevered pool on a porch-deck with leger-hangy-things....
Oh yea, I was going to state that I used to double every third joist (full length of course) just for poop & giggles. I'm going to bed, tired
Thom Huggett
03-21-2012, 10:30 AM
I wouldn't use that method of attachment if the deck is still cantilevered, but in my opinion this method of fastening the ends of the new joist to the structure would be acceptable provdied the wood tail pieces that rest within the block foundation are solid . I would also expect to see columns supporting the other end of the joists.
Wow, a lot of electrons were used up on this one! I think Ken got it right...and the issue of balcony vs deck is irrelevant to the question. The 2006 IBC live loading for balconies was 100 or 60 psf, but under the 2009 IBC you design both for the live load of the occupancy the deck/balcony serves.
From a structural standpoint, if the ends of the new joists are supported on a post and beam structural system (not cantilevered) the situation is acceptable.
Kristi Silber
03-21-2012, 12:43 PM
Wow, a lot of electrons were used up on this one! I think Ken got it right...and the issue of balcony vs deck is irrelevant to the question. The 2006 IBC live loading for balconies was 100 or 60 psf, but under the 2009 IBC you design both for the live load of the occupancy the deck/balcony serves.
From a structural standpoint, if the ends of the new joists are supported on a post and beam structural system (not cantilevered) the situation is acceptable.
Oh, good! A SE came and added his bit to the discussion. But I don't get it - if the situation is dependent on there being support for the new joists, making the structure not cantilevered, that means that whether it is a deck or balcony (by the IRC definitions) does make a difference. No? (Just for clarification.)
And out of curiosity...I was thinking if the decking near the wall is screwed to both new and old joists, that could help support some of the weight on the new ones, while nails might not be so effective because they're more likely to come out. Does that make sense, or am I imagining things?
Billy Stephens
03-21-2012, 12:54 PM
Wow, a lot of electrons were used up on this one! I think Ken got it right...and the issue of balcony vs deck is irrelevant to the question. The 2006 IBC live loading for balconies was 100 or 60 psf, but under the 2009 IBC you design both for the live load of the occupancy the deck/balcony serves.
From a structural standpoint, if the ends of the new joists are supported on a post and beam structural system (not cantilevered) the situation is acceptable.
Oh, good! A SE came and added his bit to the discussion. But I don't get it - if the situation is dependent on there being support for the new joists, making the structure not cantilevered, that means that whether it is a deck or balcony (by the IRC definitions) does make a difference. No? (Just for clarification.)
And out of curiosity...I was thinking if the decking near the wall is screwed to both new and old joists, that could help support some of the weight on the new ones, while nails might not be so effective because they're more likely to come out. Does that make sense, or am I imagining things?
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And just what is an SE?
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Jerry McCarthy
03-21-2012, 03:56 PM
Serious Engineer. :D
Definition of an Engineer:
What is the definition of an engineer? Answer: Someone who solves a problem you didn't know you had, in a way you don't understand.
Door Guy
03-21-2012, 04:11 PM
Serious Engineer. :D
Definition of an Engineer:
What is the definition of an engineer? Answer: Someone who solves a problem you didn't know you had, in a way you don't understand.
You forgot to add: With an expensive way to fix it. If your an engineer, we are JUST kidding.
BridgeMan
03-21-2012, 04:21 PM
. . If your an engineer, we are JUST kidding.
Or putting it another way (as most of us learned in 3rd or 4th grade)--If you're an engineer, we are JUST kidding.
By the way, engineers don't set or determine prices for work or materials being performed according to engineering standards, designed to keep people safe and alive.
Michael Kober, P.E.
Door Guy
03-21-2012, 04:43 PM
Or putting it another way (as most of us learned in 3rd or 4th grade)--If you're an engineer, we are JUST kidding.
By the way, engineers don't set or determine prices for work or materials being performed according to engineering standards, designed to keep people safe and alive.
Michael Kober, P.E.
Michael, no intension to insult you. Please accept my apology. I know you don't set the costs for design, repairs or materials. Good catch on the your and you're:D I deserved it...
Billy Stephens
03-21-2012, 04:45 PM
Serious Engineer. :D
Definition of an Engineer:
What is the definition of an engineer? Answer: Someone who solves a problem you didn't know you had, in a way you don't understand.
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Let's give the man an opportunity to respond.( not a PE.)
*SE , CBO ?
Self Employed, Certified Building O something ?
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Kristi Silber
03-21-2012, 04:59 PM
Or putting it another way (as most of us learned in 3rd or 4th grade)--If you're an engineer, we are JUST kidding.
By the way, engineers don't set or determine prices for work or materials being performed according to engineering standards, designed to keep people safe and alive.
Michael Kober, P.E.
You're picking on someone's grammar, and following it with a sentence like that?! How can you perform materials according to anything?
Grammar is obviously not a huge concern around here, so singling anyone out is silly. Play nice! Everyone! Jerry, was that meant to be a joke? I mean, it's a good thing someone can identify problems you guys miss, and understands how to fix them.
Billy Stephens
03-21-2012, 05:11 PM
You're picking on someone's grammar, and following it with a sentence like that?! How can you perform materials according to anything?
Grammar is obviously not a huge concern around here, so singling anyone out is silly. Play nice! Everyone! Jerry, was that meant to be a joke? I mean, it's a good thing someone can identify problems you guys miss, and understands how to fix them.
The Bridge man is a PE. and is Qualified to write a remedy.( not Silly)
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We don't know who this man that blessed the bolt on is.
Passive–aggressive behavior - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Passive%E2%80%93aggressive_behavior)
Aggression is Aggression overt or other wise.
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Jerry Peck
03-21-2012, 05:29 PM
SE , CBO ?
SE would be Structural Engineer, which is a field of Professional Engineer (PE).
A PE can have their engineering in many things, mechanical, electrical, chemical, civil, etc., the SE just clarifies that his engineering is in structural.
CBO is Certified Building Official.
Billy Stephens
03-21-2012, 05:40 PM
SE would be Structural Engineer, which is a field of Professional Engineer (PE).
A PE can have their engineering in many things, mechanical, electrical, chemical, civil, etc., the SE just clarifies that his engineering is in structural.
CBO is Certified Building Official.
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I'm sure the Gentleman can answer on his own.
Systems Engineer as in Mechanical Code Enforcement came to mind as well.
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Jerry Peck
03-21-2012, 06:31 PM
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I'm sure the Gentleman can answer on his own.
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I'm sure he can, but, as YOU and the rest of us do, we answer when we know the answer.
The Gentleman STILL can answer, I took off the handcuffs and the gag (so he could not type or use a speech recognition program to answer you) so he is now on his own. :p
Mr. The Gentleman, be forewarned of this Billy type guy here. :D
Billy Stephens
03-21-2012, 06:44 PM
I'm sure he can, but, as YOU and the rest of us do, we answer when we know the answer.
The Gentleman STILL can answer, I took off the handcuffs and the gag (so he could not type or use a speech recognition program to answer you) so he is now on his own. :p
Mr. The Gentleman, be forewarned of this Billy type guy here. :D
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As I Noticed The Gentleman was on Line and Choose Not to Respond ( at this time ) He may be rethinking His Structural Comment. ;)
* some of those Code Enforcements Guys can be like that. :D
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BridgeMan
03-22-2012, 12:25 AM
Mr. The Gentleman, be forewarned of this Billy type guy here. :D
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For clarification, that would be the Billy type guy who likes to use lots of dots.
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I wonder why--was he "dot-deprived" as a child?
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Garry Sorrells
03-22-2012, 04:00 AM
Thom,
You stated "...From a structural standpoint, if the ends of the new joists are supported on a post and beam structural system (not cantilevered) the situation is acceptable...."
Just to clarify my understanding.
Are you saying as a SE (per the picture) that the use of the two bolts is an adequate support and connection for the deck at the house?
Billy Stephens
03-22-2012, 05:20 AM
.
.
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For clarification, that would be the Billy type guy who likes to use lots of dots.
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I wonder why--was he "dot-deprived" as a child?
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....
Man.
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I Gots to Get Me Some of Dem Dots...
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:D
Jerry McCarthy
03-22-2012, 10:34 AM
Chuck confirmed his photo is of a deck so why all the dissertations?
Decks are supported from the ground, balconies are not. Stairs play no part unless they are part of the deck support system. The IRC and CBC are clear on the difference between a deck and a balcony.
BTW, note that the bolting connections of the sistered joist where not staggered. This could easily lead to a split out and failure. Still need an SE to bless it.
Jerry McCarthy
03-22-2012, 10:41 AM
A closer view. :o
Garry Sorrells
03-22-2012, 10:59 AM
Jerry M.,
I had tried to describe that concern to Kristi in post #54. Hope your description as ":..a split out and failure..." makes it clearer.
Maybe Thon will clear it up as a SE. Even though it may not be acceptable in MN but may be in CA.
The back and forth on what type of deck really was not the basic issue with the OP pict., think it was more of some fun and banter.
Have to ask, what if the platform is hung from above (cables), what is it?
And the thread continues..................
Kristi Silber
03-22-2012, 11:16 AM
Garry, what makes you think I don't understand what you're saying? I understand it fine, I just don't agree with it. Thom the SE already stated his position, he said it was acceptible. Whether it's a deck or a balcony IS important because it determines the stresses on the bolts and joists - not only how much, but what direction.
If suspended with cables from the building from which it's accessible, it's a balcony.
Chuck confirmed his photo is of a deck so why all the dissertations?
Decks are supported from the ground, balconies are not. Stairs play no part unless they are part of the deck support system. The IRC and CBC are clear on the difference between a deck and a balcony.
BTW, note that the bolting connections of the sistered joist where not staggered. This could easily lead to a split out and failure. "Easily"? Perhaps on a balcony, but far less likely on a deck; the 2X8 is also short and well supported at the wall and the bolts are relatively far apart. Still need an SE to bless it. On-site, you mean?
It seems strange to me that people seem so convinced this wouldn't work.
Billy Stephens
03-22-2012, 12:16 PM
Sounds good on paper, but should the deck collapse after being filled with many tons of people the owners have invited over for the grand house warming-party, you know the question that will be raised--"Why didn't our home inspector tell us to have an engineer take a look at it, when he knew (or should have known) it doesn't meet Code?"
Competent general contractors are not allowed to practice engineering, and asking them to do so is risky, if not illegal.
Garry, what makes you think I don't understand what you're saying? I understand it fine, I just don't agree with it. Thom the SE already stated his position, he said it was acceptible. Whether it's a deck or a balcony IS important because it determines the stresses on the bolts and joists - not only how much, but what direction.
If suspended with cables from the building from which it's accessible, it's a balcony.
Chuck confirmed his photo is of a deck so why all the dissertations?
Decks are supported from the ground, balconies are not. Stairs play no part unless they are part of the deck support system. The IRC and CBC are clear on the difference between a deck and a balcony.
BTW, note that the bolting connections of the sistered joist where not staggered. This could easily lead to a split out and failure. "Easily"? Perhaps on a balcony, but far less likely on a deck; the 2X8 is also short and well supported at the wall and the bolts are relatively far apart. Still need an SE to bless it. On-site, you mean?
It seems strange to me that people seem so convinced this wouldn't work.
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The Bridge man is a PE and has not signed off on the shown bolt up.
* have you read his post?
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Garry Sorrells
03-23-2012, 05:46 AM
A thread that just keeps on giving.
Kristi, Congratulations on being 100 post.
Billy, Congratulations for being first on page 2.
Reading Billy's re-quoting of BridgeMan's comment, "Competent general contractors are not allowed to practice engineering, and asking them to do so is risky, if not illegal." raised an interesting thought about who is qualified to offer an assessment of structural issues. In Oregon (BridgeMan location) it may be that only a SE can address a constriction design issue. While other states allow a Contractor (typically Licenced) to make a determination of structural issues. Usually stated as a qualified professional (or something similar). Contractors routinely make structural design and engineering decisions. Those decisions are based on the accepted or required building practices which have been at some point signed off by some engineering authority. Thinking back over the years I can not remember but one occasion that a SE called in actually sat down and did the actual calculations for their offered proposed solution to a problem. Most of the time the SE as the does the Contractor rely on the prescribed standards of their jurisdiction to evaluate a situation. Reapplying someone elses work every day. A contractor does not mathematically determine the size of material for a span, they use a prescribed table for that determination. Like a SE the Contractor takes the responsibility for their evaluation and reasoning. Contractors don't practice structural engineering, they apply the engineering standards as locally required.
Not casting any shadow over the SE profession nor wanting to start an argument. Just posting an observation and thought.
Garry Sorrells
03-23-2012, 06:05 AM
Wow, a lot of electrons were used up on this one! I think Ken got it right...and the issue of balcony vs deck is irrelevant to the question. The 2006 IBC live loading for balconies was 100 or 60 psf, but under the 2009 IBC you design both for the live load of the occupancy the deck/balcony serves.
From a structural standpoint, if the ends of the new joists are supported on a post and beam structural system (not cantilevered) the situation is acceptable.
Thom,
Still would be interested in your opinion on the attachment and support of the deck to the house structure, in general or Oregon specific. As a SE would you accept the two bolt pattern as seen in the picture as being adequate engineering design?
Garry Sorrells
03-23-2012, 06:37 AM
Kristi,
Billy and I seem to read Thom's response to as directed as the deck being supported by post and beam and if so making it not cantilevered therefore acceptable in the aspect of cantilevering. It may be parsing of the the sentence, but still question the bolting method.
Why is it hard to accept? 40 years of building experience. I may be wrong and would not be the first time. If I am wrong I want to understand why.
Jerry McCarthy
03-23-2012, 10:51 AM
"It seems strange to me that people seem so convinced this wouldn't work."
Kristi
Strange? The original cantilevered joist look a bit aged & deteriorated in the photo put up; however, none of us other than the original poster have been on site so all of our opinions are based on a photo that is basically incomplete.
I opined based on 61 years of construction experience and from a partial photograph and from what I see I would no sooner go on that deck than bungee jump off a bridge. "May be all right" is not good enough for these old eyes and until a state licensed SE makes a thorough site inspection of that repaired deck we will probably never know the extent of structural stability of that "repaired" deck?
Ask yourself this; what would you say to your client if they asked “is the deck safe?”
Kristi Silber
03-23-2012, 11:57 AM
Whew! Nice to not have to wait for the whole page to download.
Billy and I seem to read Thom's response to as directed as the deck being supported by post and beam and if so making it not cantilevered therefore acceptable in the aspect of cantilevering. It may be parsing of the the sentence, but still question the bolting method.
I'm afraid I don't understand, "if so making it not cantilevered therefore acceptable in the aspect of cantilevering." I was under the impression that Thom was aware of the attachment method, but I don't know. At any rate, I don't take his assessment as the final word, either, since he knows no more than any of us about the structure as a whole.
It's not the doubt that it would work that I find strange, it's the conviction that it wouldn't - the definitive answers people give, based on so little information. People were judging it before even knowing if the whole structure was cantilevered or supported elsewhere, and to my mind that is a pretty critical issue.
I don't know whether I would tell a client if it's safe or not because I don't know anything about the rest of the deck. What if this is only four feet wide, from wall to railing? That makes a big difference in terms of both live and dead loads, versus a deck that is 10' wide.
As I said multiple times before, my main point is that using the stubs to attach new joists doesn't seem to me in itself problematic. If the attachment is not adequate it can be reinforced, rather than taking the whole thing apart and putting up a ledger board.
Thom Huggett
03-26-2012, 10:27 AM
Wow, what a lot of time people have on their hands! I had no idea what a stir I created while taking a long weekend. I don't have time to read all the posts, but here is my reply....
First of all, I am a Registered Professional Civil and Structural Engineer in California, but I try not to take myself too seriously (Serious Engineer?:) ). I am also an ICC (International Code Council) Certified Building Official and Certified Plans Examiner. I have served as the Building Official for a California city and county, but am now Principal Structural Engineer in Contra Costa County, which is located in the east San Francisco bay area. But enough about me....
The original question was whether joists could be attached to the end of the existing stubbed joists, with the assumption that the existing joists are sound. The simple answer is yes, assuming that the existing joists are not asked to support too much load. There are 2 different ways that the load could be applied; as a continuation of the cantilever (balcony?), or as the reaction from simple span joists (the other end supported by posts and beam). There are many factors to consider, but probably the former would not work. However the latter, taking into account the span length, etc., could be made to work. You might have to add an extra bolt, but in theory it should work. An added ledger would serve no purpose, although blocking between the added joists would be advisable.
As I stated before, the only difference between a balcony and a deck, from a structural standpoint, would be the live load that must be applied to the structure. Under the 2006 IBC there is a difference, however under the 2009 IBC the live load is equal to that of the occupancy that the deck/balcony serves, which would be the same in either case.
From glancing through the posts it may be that balcony/deck concern is that the joists for a balcony are usually cantilevered while for a deck they are usually simply supported by posts and beams. My response to this concern is in my 3rd paragraph above.
Here is a better definition of engineering:
The practice of:
Using materials whose properties that we don't really understand,
In conditions that we don't really know how to analyze,
To withstand forces that we can't predict,
And to do all in such a way that the general public has no idea as to the extent of our ignorance. :D
Garry Sorrells
03-26-2012, 02:12 PM
Thorn,
Thanks for your reply. Yes, seems a lot about what is not seen in the picture, some of it is just having a little fun with each other.
Part of you respoce, "... You might have to add an extra bolt, but in theory it should work...." ...."...blocking between the added joists would be advisable..." goes along with Jerry M.and my thought that additional bolts would be necessary. Most all seem to agree that what is depicted int he picture needs more than what is there art present. Though I would have approached the attachment differently.
Kristi Silber
03-26-2012, 03:13 PM
Now Garry, it wasn't just you and Jerry M who said additional attachment might be necessary - I said the same thing. In fact, all along I've been saying the same thing Thom said, and Jerry M told me I "couldn't be more wrong."
Thanks, Thom, for coming back into the fray! What a crazy thread.
Thom Huggett
03-26-2012, 04:50 PM
Thanks for the kind words.
I have been following this website for a while, and I think, for some of these situations, if we were all sitting in a room together discussing them there wouldn't be quite so many misunderstandings. It's sometimes hard to express yourself in writing, even when using the little smile guys :p . I enjoy the exchanges and the photos of situations that people share, and save them for examples to share with my staff.
Kristi Silber
03-26-2012, 05:44 PM
Ain't that the truth! Misunderstandings, and time lapsing between replies - look at how much discussion would have been extraneous if we had known earlier that this was a deck.
But some of us obviously don't mind discussing tangential things anyway!
Thom, I was wondering about this statement:
As I stated before, the only difference between a balcony and a deck, from a structural standpoint, would be the live load that must be applied to the structure. Under the 2006 IBC there is a difference, however under the 2009 IBC the live load is equal to that of the occupancy that the deck/balcony serves, which would be the same in either case
It seems like if this case were a balcony, it would depend not only on the load, but where that load is distributed. Since the supports are not continuous through the wall, there's a pivot point at the bolt furthest from the wall, with the structure being held in place by the other bolt: perfect situation for the splitting Garry and Jerry M were talking about, since the forces are in opposite directions and would act like a pry bar. The force on the bolts would grow the further away the load was. So if you had 4 people standing 3 feet from the wall it may be safe, but not if the deck is 10 wide and they're at the railing.
Whereas with a post-and-beam deck, the load is of course distributed over more points, and it's also straight down along the whole length of the joist. So the bolts are sharing the load and the prying action stops, since the force on them is in the same direction.
Does that make sense? I'm just wondering if I'm thinking of it correctly.
Thom Huggett
03-27-2012, 11:34 AM
Kristi,
As a cantilevered balcony the connection shown is most likely inadequate. The bolts attaching the new joists to the old ones need to develop what we engineers call a resisting moment couple, the prying action that you mentioned.
The IBC does not require you to check for any concentrated loading (except for the guardrail), just a uniform live load based on the occupancy of the main building, which in this case is 40 pound per square foot (psf), plus the dead load of the balcony itself.
If we assume the balcony cantilevers 5'-0", the joists are 16" o.c., and the dead load is 10 psf, the moment that the bolts must resist is:
(40psf + 10psf) x (1.33' o.c.) x (5') x (5'/2) = 831.25 ft-lbs
If the bolts are 12" apart, each bolt must resist:
(831.25 '#) / 1'-0" = 831.25#
Which is fairly substantial load for a single bolt to resist, so you would probably need 2 or 3 additional bolts to reduce the load to each bolt. The connection should definitely be designed by an engineer.
However, if there is are posts and a beam supporting the ends of the new joists away from the building, the load to the bolts is only from simple span loading (with no moment action), which is:
(40psf + 10psf) x 1.33' x (5'/2) = 166#, or 83# per bolt, which a 1/2" bolt carries easily.
These over-simplified calculations confirm what you are thinking, so yes, you are correct.:)
Kristi Silber
03-27-2012, 01:16 PM
Thanks, Thom! Great answer, with the math and everything!
Randy Mayo
03-27-2012, 07:21 PM
Chuck,
If I am looking at the picture correctly the deck joists are butted up against the wall and spliced to the stubs with bolts, then this is absolutely NOT acceptable. A bolted splice like that in a cantilevered configuration IMO is subject to sudden failure. Even if you propped the outer end that splice is still not allowed. I would red flag that as a dangerous condition and recommend nobody use it until replaced or strengthened properly.
BridgeMan
03-27-2012, 10:25 PM
As a cantilevered balcony the connection shown is most likely inadequate. The bolts attaching the new joists to the old ones need to develop what we engineers call a resisting moment couple, the prying action that you mentioned.
If we assume the balcony cantilevers 5'-0", the joists are 16" o.c., and the dead load is 10 psf, the moment that the bolts must resist is:
(40psf + 10psf) x (1.33' o.c.) x (5') x (5'/2) = 831.25 ft-lbs
If the bolts are 12" apart, each bolt must resist:
(831.25 '#) / 1'-0" = 831.25#
Which is fairly substantial load for a single bolt to resist, so you would probably need 2 or 3 additional bolts to reduce the load to each bolt. The connection should definitely be designed by an engineer.
Sorry, Thom, but I'm confused--you computed a bending moment for a point where the cantilevers stub out of the existing foundation (using 5'/2 for the moment-arm, half the length of the 5' cantilever), but then equated that to a resisting moment-point midway between both of the bolts in each connection. Not quite realistic, is it? In that the centroid of the bolts is much closer to the point of load, meaning the actual bending moment at the bolts would be considerably less than what you're showing. But you completely ignored the moment applied by dead and live loads on the rest of the deck (beyond the cantilever) but not supported by the exterior columns. Meaning your numbers might not be too far off anyway.
P.S. Forgive my ignorance if I'm out of line, as I'm not a design engineer, having spent only 2 years "behind the board" before getting into field construction work more than 40 years ago.
As an aside, are we shooting for 200 posts on this topic?
Thom Huggett
03-28-2012, 08:12 AM
BridgeMan,
I did mention that the calcs were "over-simplified", however most engineers will take the conservative approach that I took.
Randy,
The assumption was that the existing cut joists were of sound material. Another assumption must be that the bolts meet all end and edge spacing distances as required by the NDS (National Design Specification for Wood Construction) by the AF&PA. If that is also the case, this connection is, or could be made to be, code compliant.
Randy Mayo
03-28-2012, 09:01 AM
Thom
That is a moment or bending splice, as far as I know there is no approved lap splice method for a bending or moment splice in wood.
Jerry McCarthy
03-28-2012, 10:16 AM
I have a stake.... can somebody bring a hammer? ;)
Thom Huggett
03-28-2012, 10:31 AM
Randy,
I'm not sure what you mean by "approved", but most situations can be designed if not specifically disallowed by the code. A wood moment connection is not a very practical connection due to the geometry of the connection and size of the bolts necessary, nor would it be very reliable, especially exposed to the weather, but it is possible. The most common method for addressing this situation is to lap the joists along-side the existing joist back into the building, but I don't think that is possible in this situation.
I not sure this one is going to die very soon, Jerry.
Randy Mayo
03-28-2012, 11:30 AM
Thom
If Jerry will hang on a little longer...
By approved I mean I can find no reference in the NDS or any other code that prescribes an acceptable "moment splice" design method for connecting two wood beams made from standard sawed lumber. There is an approved moment splice method to connect glu-lam beams cut for shipping but the splice is designed at the inflection point or the point of minimum moment. Extending a new joist back into the wall just replaces the original joist and a splice is no longer needed. At first I thought the new joist were cantilevered and supported by just bolting to the old joist, which is the location with the highest moment (worst case). If the new joists were also supported at the outer end with a beam then the splice would still have some moment to a lesser degree. There are a few other items concerning splices in general I wanted to share with home inspectors:
A splice designed for one material like steel cannot be copied and applied to wood.
There are four basic forces to consider in splice design in any material; bending, shear, tension and compression.
The four basic forces listed typically change with location of the splice. For example a splice designed at mid span may be totally unacceptable if the same splice configuration was used on a splice over a support.
Jerry, you can drive the stake now.....
Joseph Ehrhardt
03-28-2012, 11:33 AM
How about this to throw in the mix, I was inspecting stucco cracks yesterday morning and observed a cantalever galvanized steel beams supporting a balcony supporting a deck transferring re-actions through out the foundation and wall assemblies.
I have lost complete faith in the AHJ ability to inspect framing and cladding sytems, and with due respect to that code enforcement, they may not have taken out a permit
Billy Stephens
03-28-2012, 11:44 AM
How about this to throw in the mix, I was inspecting stucco cracks yesterday morning and observed a cantalever galvanized steel beams supporting a balcony supporting a deck transferring re-actions through out the foundation and wall assemblies.
I have lost complete faith in the AHJ ability to inspect framing and cladding sytems, and with due respect to that code enforcement, they may not have taken out a permit
.
No Worries,
The Same Folks put up that Privacy Fence along the back parking lot. :D
.
Thom Huggett
03-28-2012, 01:21 PM
Joseph,
Looks like a retrofit job...maybe the deck joists were too springy when they finished construction so they added the steel framing to stiffen them up. Are the cracks due to flexing of the steel members due to loading or temperature fluxuations? Where are the cracks? The structural solution may be ok, depending on the sizing of the members and the attachment of the steel members at the lower level.
Sorry, I just couldn't let it go....
Kristi Silber
03-28-2012, 01:40 PM
Randy, it seems like you've jumped into the conversation without reading previous posts. Since there are over 100 of them, I certainly don't blame you for that! However, it seems to me your first post in the thread gives an opinion based on little knowledge of the actual structure, since you apparently don't know whether it's supported elsewhere or not. I think this has been a common error in many of the posts in this thread. I simply don't see how it's possible to say much of anything concrete about the structural stability of the splice without knowing more about the deck.
BridgeMan and Randy,
Thom's post that showed calculations was in response to a question I posed about the forces that would come into play if the structure were a balcony vs. a deck. I don't think it was meant to be applied directly to this situation, since obviously there are assumptions and simplifications made.
And a couple questions:
What happens when something is built in a way that is not addressed by codes? If this were a splice everyone agreed was structurally sound, but it was neither accepted nor rejected by the codes or standards, would it be a problem?
I've brought this up a few times already, but no one has addressed it. Wouldn't the decking, if screwed into both old and new joists, add some stability to the splice?
Jerry McCarthy
03-28-2012, 02:08 PM
All the theories in the world are meaningless on this thread as the posted photo is only a partial, we don’t know the current structural stability or current condition of the original cut-off cantilevered section, how the support beam was installed, length of deck projection, condition of the decking; therefore, debating whether the deck will support any loads imposed is meaningless and a waste of time. Don’t we all agree it needs a full evaluation by a competent SE? Please somebody, bring a sledge hammer!
Randy Mayo
03-28-2012, 02:40 PM
Kristi
The section below is from the 2006 IRC and commentary. I think this address your question. IRC codes are prescriptive, as long as you follow them to the letter you should be fine. If you deviate from the code or have a situation that does not fit then the local code official (AHJ) has the authority to interpret the code. The AHJ can make the call to require an engineer's design and certification that it meets or exceeds the intent of the code. If a builder knows in advanced something is not going to be covered by code they can supply an engineer's certification or design up front for approval.
R301.1.3 Engineered design. When a building of otherwise conventional construction contains structural elements exceeding the limits of Section R301 or otherwise not conforming to this code, these elements shall be designed in accordance with accepted engineering practice. The extent of such design need only demonstrate compliance of nonconventional elements with other applicable provisions and shall be compatible with the performance of the conventional framed system. Engineered design in accordance with the International Building Code is permitted for all buildings and structures, and parts thereof, included in the scope of this code.
Commentary - Generally, proper application of the IRC requires a clear understanding of and adherence to its prescriptive limitations, which are based on conventional construction. However, a building may contain structural elements that are either unconventional or exceed the prescriptive limitations of the code. This is acceptable, if these elements are designed in accordance with accepted engineering practice by a design professional.
As to your last question about the deck boards adding strength to the deck. Individual deck boards laid perpendicular to the joist have no impact on the strength of the deck and for design purposes they are considered dead load. If the deck boards are laid at 45 degrees that can help stiffen the deck against lateral movement but would still be considered dead load for vertical load support. Wood design is not as exact as say steel or concrete design due to the fact no two boards have the exact same engineering properties. Factors such as moisture content, knots, growth ring spacing impact the strength of the lumber. To compensate engineering guidelines have large safety factors built into design formulas to account for all the unknown variables.
Kristi Silber
03-28-2012, 02:40 PM
Jerry, what's wrong with discussing the theoretical? The whole thread was about the theoretical, for the reasons you point out. You had your say, why do you mind others discussing it? I, for one, am learning something by it.
Kristi Silber
03-28-2012, 02:58 PM
Thanks, Randy! That was a great reply. Interesting that decking laid at a 45 degree angle to the joists help stiffen it. I can understand what you're saying about decking in general not adding strength, but speaking strictly from a theoretical and not a design standpoint it seems like joists that are flush together might be different. But anyway, it's a trivial little thing, I was just curious.
Jerry McCarthy
03-28-2012, 05:44 PM
Kristi
I may be a firm believer in Epicureanism, but I ain’t no Lucretius. :D
Billy Stephens
03-28-2012, 06:08 PM
Kristi
.
I may be a firm believer in Epicureanism, but I ain’t no Lucretius. :D
.
Oh Yeah,
Well I Might Eat Hog but I ain't eating any Part that Walked,Talked, Heard or Processed Anything. ;)
.
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