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Thread: attic supports
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01-26-2009, 09:42 PM #1
attic supports
hey all
1924 house with new roof. went into the attic and this is what i found. was afraid to walk across it because nothing to hold on to. what the hell is holding it up and how about the support for that cast vent pipe--think it needs alittle help--what do you all think
thanks
charlie
Similar Threads:
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01-26-2009, 09:51 PM #2
Re: attic supports
sorry pic didn't upload--new computer with vista--vista sucks
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01-26-2009, 11:20 PM #3
Re: attic supports
Dang Charlie you seem to find them don't you. Better call for a SE. On that. looks like the framer was not up to par. on a few things.
Best
Ron
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01-27-2009, 04:36 AM #4
Re: attic supports
The house is 84 years old and Charlie made no mention of a sagging roof or other structural symptoms. I would say the framer did pretty well. Assuming the span calculations are OK, what's missing?
Darrel Hood
DILIGENT PROPERTY SERVICES
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01-27-2009, 06:27 AM #5
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01-27-2009, 06:38 AM #6
Re: attic supports
There are at least two, and possible three (one behind the camera view) support holding the ridge board up, making that into a ridge beam (a structural ridge), except that the ridge beam appears to only be a 1x and not a 2x (Charlie can clarify that for us - zooming in on the photo shows the 2x edge of the ridge beam support to be wider than the ridge beam).
With a ridge beam, collar ties are not required or needed.
Not saying the ridge beam supports are properly sized or anything, just that they are there.
Last edited by Jerry Peck; 01-27-2009 at 09:07 AM. Reason: speelin'
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01-27-2009, 07:51 AM #7
Re: attic supports
50% or more of my inspections are done on 1930 and older homes. This method of framing is very common...in fact it is the norm. The ridge board is always a 1X4 or 1X6 and rafters are nailed directly to it. The load is transfered to the exterior walls, with little to no center support. This style of framing does not alarm me at all UNLESS there is evidence of sagging are separation. Remember guys.....IT IS WHAT IT IS. You cannot, no matter how hard you argue, turn a 1930's home into a 2009 home.
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01-27-2009, 08:35 AM #8
Re: attic supports
thanks everyone
charlie
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01-27-2009, 08:53 AM #9
Re: attic supports
Makes it into a ridge beam??????????????
Often when framing a home the ridge board was supported temporarily to keep it level and from sagging until the rafters were attached thus making it self supporting. Older construction would often not even use a ridge board.
Sometimes the framing crew removed the supports and sometimes they did not. Those supports were often left in place for switches & attic lights or to mount a low voltage transformer to.
What you are looking at is perfectly fine from a framing standpoint for the time it was built. I would not disagree if you recommended collar ties to resist uplift but not as a defect. When was the home built?
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01-27-2009, 09:05 AM #10
Re: attic supports
JP: In my experience the member to which you are referring is a ridgeboard and not a ridge beam. I find no reference in the IRC to ridge beams except as they are required in 802.3 for support of roofs under a 3/12 pitch. In any event I cannot justify calling a 1X6 or 1X8 a beam (as it refers to a girder) under any circumstances. So then, I don not believe this should be referred to as a “ridge beam”. You are welcome to call it what you like, I just won’t join in with you.
The supports that are present, in my opinion and in my experience, are temporary supports used by the framers when erecting the roof framing. Again, just my opinion.
Collar ties are required for wind resistance and the requirement for their presence is not dependent on whether or not you call the ridgeboard by its proper name.
REFERENCES FROM THE IRC – I found nothing in the NDS literature to the contrary.
Wood roof-ceiling construction must comply with Section R802 or AF&PA/NDS, National Design Specification for Wood Construction.
R802.2 Design and construction. The framing details required in Section R802 apply to roofs having a minimum slope of three units vertical in 12 units horizontal (25-percent slope) or greater. Roof-ceilings shall be designed and constructed in accordance with the provisions of this chapter and Figures R606.11(1), R606.11(2) and R606.11(3) or in accordance with AFPA/NDS. Components of roof-ceilings shall be fastened in accordance with Table R602.3(1).
R802.3 Framing details. Rafters shall be framed to ridge board or to each other with a gusset plate as a tie. Ridge board shall be at least 1-inch (25 mm) nominal thickness and not less in depth than the cut end of the rafter. At all valleys and hips there shall be a valley or hip rafter not less than 2-inch (51 mm) nominal thickness and not less in depth than the cut end of the rafter. Hip and valley rafters shall be supported at the ridge by a brace to a bearing partition or be designed to carry and distribute the specific load at that point. Where the roof pitch is less than three units vertical in 12 units horizontal (25-percent slope), structural members that support rafters and ceiling joists, such as ridge beams, hips and valleys, shall be designed as beams.
Traditional practice is to provide a ridgeboard between opposite rafters as a nailing base and to provide a full bearing for the rafter.
Collar ties or ridge straps to resist wind uplift shall be connected in the upper third of the attic space in accordance with Table R602.3(1). Collar ties shall be a minimum of 1-inch by 4-inch (25 mm by 102 mm) (nominal), spaced not more than 4 feet (1219 mm) on center.
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01-27-2009, 09:11 AM #11
Re: attic supports
If you and Jeff will notice, *IF* that were 2x instead of 1x (as I noted), and *IF* that is supported (it is, as I noted, but not well supported, as I also noted), then it CAN BE a "ridge beam" and, with it being a "ridge beam" ... NO collar ties are needed.
If you go back and read my post again, I suspect you will see what I stated.
Yes, it MAY have been there for temporary support, or it MAY have been there for permanent support with the other aspects having been done incorrectly. Had the other things been done correctly, then it MAY have been intended to be a structurally supported "ridge beam", which would not need collar ties.
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01-27-2009, 09:11 AM #12
Re: attic supports
I agree with Jeff completely. Other than support for the stack, the only thing missing is the collar ties. The rafters might be undersized by today's standards, but that's typical.
The lack of collar ties will only be an issue in the event of a hurricane (or tornado, for you inlanders). Their purpose is to tie opposing rafters together at the ridge, to resist negative pressure. Typically, one rafter is through-nailed to the 1x ridge board (not ridge "beam") and the opposing rafter is toenailed (you obviously can't through-nail it when the opposing rafter is present). The toenailed connection doesn't provide much resistance to being pulled out from the negative pressure of huricane force winds, so the colar ties are required.
That's why the code requires them to be installed in the upper 1/3 of the roof. Many builders believe that collar rties are intended to hold the bearing walls togther, but that's the purpose of the attic floor joists.
Note that if straps are used over the tops of the rafters to tie oppsing rafters together, teh collar ties are nort required. It's unlikely that straps were used in older construction, but there's no real way to confirm this.
The American Wood Council Wood Frame Construction Manual has some good information. American Wood Council Free Download Library
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01-27-2009, 11:21 AM #13
Re: attic supports
Jerry..Where do you get the "IF'S". You clearly stated that because there are supports holding the ridge board up that that amde it a ridge beam.
Just because there are supports to the ridge doesn't make it a beam.
I'm in total aggreeance with Jeff also. Collars ties and strap plumbing is all that should be noted as "not to todays standards".
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01-27-2009, 11:44 AM #14
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01-27-2009, 11:45 AM #15
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01-27-2009, 11:49 AM #16
Re: attic supports
Right here:
(underlining has been added)
Thus, the design appears to be that that was INTENDED TO BE a ridge beam, and, in fact it was supported.
In fact, *it has also done its job for 80+ years ... HOWEVER, as I also stated, that does not make it correct.
*IF* that defacto "ridge beam" was not acting as a "ridge beam", without the collar ties you would most likely see sagging in the ridge and the exterior bearing walls having been pushed outward near their center along the top.
*BECAUSE THAT IS acting as* a defacto "ridge beam" by supporting the top of the rafters, it now becomes an undersized "ridge beam" with undersized supports.
You can call it a "ridge board", 'add collar ties', and 'take out those supports' ... but ...
... you will have just changed then entire structure around.
If you do that, you will now be adding load to the exterior walls, which has gone 80+ years without that additional load. I'd be reluctant to put the additional load where it has not been.
I'd feel better about making it do what it has already been doing, taking that load down those supports - provided, of course, that all things are sized properly and there is actually a load bearing wall or column below those supports.
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01-27-2009, 11:59 AM #17
Re: attic supports
Aaron,
Being as we are applying today's code to a structure constructed decades ago under a different code (one which likely did not address uplift), here is that wording you are looking for.
- R802.3.1 Ceiling joist and rafter connections.
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- - - Collar ties or ridge straps to resist wind uplift shall be connected in the upper third of the attic space in accordance with Table R602.3(1).
I would, in addition to making sure the ridge beam and its supports and their bearing are strong enough (see my post above), simply *add straps*.
Provided the ridge beam is functioning as intended (I was not there and cannot attest to that), then you have two things you can do: 1) add collar ties; 2) add straps. BOTH provide resistance to uplift separation and satisfy the same purpose.
Me, I would chose to add the straps.
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01-27-2009, 12:22 PM #18
Re: attic supports
“Me, I would chose to add the straps.”
Me too and I would add that there is a difference between a ridge board and a ridge beam, in fact a world of difference.
Jerry McCarthy
Building Code/ Construction Consultant
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01-27-2009, 12:23 PM #19
Re: attic supports
How in the world does adding a 2X under the ridge make it a beam?
You've got me scratching my head on this one!
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01-27-2009, 01:04 PM #20
Re: attic supports
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01-27-2009, 01:08 PM #21
Re: attic supports
Yes there is a world of difference between a "ridge board" and a "ridge beam", and simply because the ridge beam is undersized does not make it a ridge board. That simply makes it undersized ridge beam.
Reconfiguring the roof structure to turn an undersized ridge beam into a ridge board just because it is an undersized ridge beam does not always make sense. One has to look at the existing load paths (with the ridge beam) and the revised load paths (with the ridge board).
With a ridge board, the load paths are down to the exterior bearing walls. Not so for a ridge beam.
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01-27-2009, 01:10 PM #22
Re: attic supports
Is it just because there aren't any collar ties that you are calling this a ridge beam?
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01-27-2009, 01:15 PM #23
Re: attic supports
Wayne,
Let's do it this way.
Suppose you went into that attic and saw a 2x12 ridge (whatever for right now) with the rafters secured (nailed) to it and it is supporting the rafters, it is supported by 4x4 posts going down to a load bearing wall.
What do you have (fill in the "whatever for right now")?
- A) ridge board
- B) ridge beam
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01-27-2009, 01:20 PM #24
Re: attic supports
JP and JM: I fully realize that there is a difference between a ridge beam and a ridgeboard. In fact, I believe I was the first to note the difference in this post.
I do not allow though, regardless what your personal opinions may be on the subject, that the ridgeboard in the photos in question is anything other than just that - a ridgeboard. And it is not a structural member, but rather something to facilitate the attachment of the rafters to one another at the ridge. Additionally, though I do not profess to have the ability to read the mind of the original designer, I cannot persuade myself (nor would I even attempt it) that this was intended to be anything other than a ridgeboard.
The ridgeboard is also not "acting" as a beam. Not by any stretch of even your imaginations. It is also not supporting the tops of the rafters. It may well be said to be stabilizing them, but it is certainly not supporting them. If it were, it would be a beam. It is not and it is not a beam. It doesn't really get much simpler than this.
Removing the "supports" will have no effect on the roof structure other than to remove from the realm of possibility even the appearance of your having a valid argument.
Aaron
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01-27-2009, 01:29 PM #25
Re: attic supports
What A. D. said.
I agree with A.D.'s statement. He said it better than this old country boy could phrase it.
It's a ridge. It doesn't become a beam until it supports something. If it's between the rafters it's a ridge. Under the rafters supporting them it's a beam.
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01-27-2009, 01:32 PM #26
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01-27-2009, 01:47 PM #27
Re: attic supports
. . .and, if you think that WE cannot agree on terminology, there's this from the AWC:
Collar Beams (collar ties)Collar beams of nominal 1x6 or 2x4 lumber are installed
in the upper one-third of the attic space to every
third pair of rafters to secure the ridge framing.
WTF?!
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01-27-2009, 01:49 PM #28
Re: attic supports
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01-27-2009, 01:57 PM #29
Re: attic supports
Go up there and remove it, then watch what happens over the new couple of decades.
AS INSTALLED .. *it is* supporting the rafters.
How much is unknown.
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01-27-2009, 02:13 PM #30
Re: attic supports
JP,
Sorry, but you're "nearly" completely wrong on this one. To be certain, we'd have to be able to see the attic floor joists. If the floor joists are continuous across the width of the attic (or lapped and properly nailed to each other at the center of the span) and are attached to the top of the exterior bearing walls (or preferrably, to the rafters), and opposing rafters are in line with each other at the ridge ( in other words, it is conventionally framed), then the ridge board serves no structural purpose.
I agree with others who have said the the "posts" are likely supports for the ridge that were installed during construction as temporary shoring. I see them all the time. It doesn't make them structural.
In fact, older buildings (200+ years), were framed with true timber "rafters", with purlins spanning between, with no ridge boards.
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01-27-2009, 03:49 PM #31
Re: attic supports
Guess I didn't make my opinion very clear as both JP and ADM appear to have misunderstood it. A ridge board helps support the rafters during installation and acts as a “tie-together” much like the sheathing that’s installed after. A ridge beam acts as a support for the roof rafters and other loads such as sheathing and roof coverings. Never heard the expression “collar beam” and at best its bad nomenclature. However, everybody needs to understand that construction terminology employed in stick-built structures varies greatly from various areas in our great nation and the only ones that are truly accurate and reflect true professional building standards are of Celtic origin and carefully imported to California.
Rafters shall be framed to ridge boards or to each other with a gusset plate as a tie. The gusset is only required for a rafter to rafter without a ridge board. On the other hand a properly sized ridge beam is capable of supporting the roof load consisting of rafters, sheathing and roof coverings.
Now shall we move on and discuss rafter purlins?
The below photos are of roof beams amd the diagrams are of ridge boards
Jerry McCarthy
Building Code/ Construction Consultant
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01-27-2009, 04:07 PM #32
Re: attic supports
Jerry,
Do you have a purlin diagram from the 1997 standard housing or building code?
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01-27-2009, 05:15 PM #33
Re: attic supports
No John, only UBC, CBC and IRC. Basically all the same and I doubt the one your after is any different, but I could be wrong?
PS: why is this thread titled "Attic Supports?" Would that not be ceiling joist?
Jerry McCarthy
Building Code/ Construction Consultant
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01-27-2009, 07:14 PM #34
Re: attic supports
I didn't misunderstand, this is what I am referring to ( Troubleshooting Guide to Residential ... - Google Book Search ), scroll down to page 45, see figure A.
And this ( Graphic Guide to Frame Construction ... - Google Book Search ), page 131, figure C.
And this ( http://ccgovernment.carr.org/ccg/per...ableroofcs.pdf ), see note at ridge for either/or (ridge board or structural ridge beam).
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01-28-2009, 07:21 AM #35
Re: attic supports
Ok when I said that a ridge beam went "under" the rafters I knew after I posted it that "nope" they (the ridge beam) can be where the rafters are secured into it.
However what the OP picture, that is not a beam! It's a ridge board. If anyone want to say "an undersized beam" well yeah! But a 1X8 ridge could also be an undersized ridge beam "IF" there were no ceiling joists to tie in the rafters or collar ties. Then a ridge beam would be required.
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01-28-2009, 07:43 AM #36
Re: attic supports
A ridge board helps support the rafters during installation and acts as a “tie-together” much like the sheathing that’s installed after. A ridge beam acts as a support for the roof rafters and other loads such as sheathing and roof coverings.
JM: Agreed that photo #1 shows a ridge beam. Photo #2 shows both a ridge beam and a ridge board.
Never heard the expression “collar beam” and at best its bad nomenclature. However, everybody needs to understand that construction terminology employed in stick-built structures varies greatly from various areas in our great nation and the only ones that are truly accurate and reflect true professional building standards are of Celtic origin and carefully imported to California.
Now shall we move on and discuss rafter purlins?
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