Deck Ledger Board

[mathew stouffer]

This house was built in 08. Flashing was installed above the ledger but the ledger was not bolted to the house. Are there exemptions for this requirement?

[Matt Fellman]

The most common exception to needing lag screws is if it's secured agaisnt movement out from the building by a wall on one (or both) ends. As in a townhouse or something else with a separation wall.

Basically, if the deck is totally free of the house except for the ledger it should be lag screwed.

[Michael Thomas]

Matt,

Can you post a link to the IRC for that exception?

Thanks

[A.D. Miller]

I am fairly certain that the Microllam member there is not intended for exterior use.

http://irc.nrc-cnrc.gc.ca/ccmc/registry/pdf/08675_e.pdf

[mathew stouffer]

The one side of the lam intersects an exterior wall but the other does not.

[Scott Patterson]

Just think about it for a moment?? OK, that's long enough!

What is holding that ledger board to the house? Those nails will pull out over time. they have no holding power for lateral movement. As folks walk, dance or do the limbo on the deck it will move and this will cause those nails to loosen and pull away.

It's great that they got the flashing, but they skimped on the bolts or lag screws!

The American Wood Councul has a great deck guide that is based on the IRC. It has become the go to document for deck design and is used by experts in litigation work. I can't post the document due to its size but you can get it from their site.
http://www.awc.org/Publications/DCA/DCA6/DCA6.pdf

[Michael Thomas]

The one side of the lam intersects an exterior wall but the other does not.

My first thought was that this "ledger" might be acceptable if it was a properly sized Microlam properly supported and restrained at both ends, but then I realized it does not appear to be continuous:

[Matt Fellman]

Matt,

Can you post a link to the IRC for that exception?

Thanks

What I was talking about without going into too much detail was when it's a balcony rather than a deck. Like on the back of rowhouses. I see them all the time without lag screws in that application. I've never looked up the code but common sense tells me when the deck is attached on the sides it can't pull away from the building without the building falling over with it.

[Wayne Carlisle]

Another thought. Glulams are usually thinker than a standard 2X. Looks like they used a air nailer on the nails, probably shooting 10's maybe 12's. 12's wouldn't even come close to penetrating deep enough to even grab a good hold. This deck will come down if nothing is done to it!

[Brandon Whitmore]

I've never looked up the code but common sense tells me when the deck is attached on the sides it can't pull away from the building without the building falling over with it.

The other concern with using nails, besides withdrawl, is shear strength concerns. Any time I see nails only, I recommend bolts be added for this reason.

[A.D. Miller]

The one side of the lam intersects an exterior wall but the other does not.

MS:

FROM THE ICC-ES


Microllam® LVL,. as with all SCL, is intended for dry service applications only.(1)


(1) All lumber, wood-based panels and proprietary engineered wood products are intended for dry service conditions.. .Dry service. is defined as the in-service environment under which the equilibrium moisture
content (MC) of lumber is 15% or less over a year and does not exceed 19% at any time. Wood contained within the interior of dry, heated or unheated buildings has generally been found to have a MC between 6%
and 14% according to season and location. During construction, all wood-based products should be protected from the weather to ensure that the 19% MC is not exceeded in accordance with the NBC 2005,
Division B, Article 9.3.2.5.

[brian schmitt]

code requires positive attachment of the ledger at 8"on center minimum and nails only do not meet the requirement.microlam not pressure treated and nails in hangers are sinkers. waffle headed nails are not galvanized or stainless. lots of problems.

[A.D. Miller]

code requires positive attachment of the ledger at 8"on center minimum and nails only do not meet the requirement.microlam not pressure treated and nails in hangers are sinkers. waffle headed nails are not galvanized or stainless. lots of problems.

BS: Agreed.


R502.2.2 Decks.

Where supported by attachment to an exterior

wall, decks shall be positively anchored to the primary structure
and designed for both vertical and lateral loads as applicable.
Such attachment shall not be accomplished by the use of toenails
or nails subject to withdrawal.Where positive connection to the
primary building structure cannot be verified during inspection,
decks shall be self- supporting. For decks with cantilevered
framing members, connections to exterior walls or other framing
members, shall be designed and constructed to resist uplift
resulting from the full live load specified in Table R301.5 acting
on the cantilevered portion of the deck.


If an exterior wall is used to support a deck, the deck framing must be positively attached to the buildingstructure. This connection design must include a consideration of both vertical and lateral loads, and the connection must be available for inspection. If it is not, this method of support is not permitted and the deck must be self-supporting.


If a deck has cantilevered framing, the framing must have a connection to its support that is designed to resist any uplift resulting from the full live load acting on the cantilevered span only. This load condition will produce maximum uplift at the support opposite the cantilevered end.

[Gunnar Alquist]

This house was built in 08. Flashing was installed above the ledger but the ledger was not bolted to the house. Are there exemptions for this requirement?

Matt,

Check out the Simpson Strong-Tie website. They have a handy guide for deck construction. Simpson Strong-Tie - Helping to Build Stronger, Safer Structures (http://www.strong-tie.com/)

[mathew stouffer]

Thanks guys

[Michael Thomas]

What I was talking about without going into too much detail was when it's a balcony rather than a deck. Like on the back of rowhouses. I see them all the time without lag screws in that application. I've never looked up the code but common sense tells me when the deck is attached on the sides it can't pull away from the building without the building falling over with it.

I would have though the same, too, if I hadn't spent a day researching deck and balcony collapses as a result of a contractor claiming I was in error for reporting as defective a similar balcony with nailed ledgers.

Deck collapse reason sought (http://www.enquirer.com/editions/1999/09/07/loc_deck_collapse_reason.html)

[Matt Fellman]

Obviously no determination (yet) as the failure point for the deck/balcony so the ledger pulling away is speculative.

Truth is for years and years ledgers were nailed and were just fine. The 'sexy' stories you read about in the news where decks fall off of houses are usually due to a rotted and failing ledger where lag screws wouldn't have helped. Of course, lag screws are way stronger and better and I'm completely behind it. But, a well nailed ledger is not the weak link from a shear standpoint. True, it can pull away, hence the code requiring screws but thick nails are very strong in a vertical loading. IMO, proper flashing is way more important than screws vs. nails for a ledger. But, both should be done just because they're so easy.

While on the topic and something I've always found curious.... So, the ledger is screwed/bolted/cemented to the house. How are the hangers attached to the ledger? That would be with nails.... and short ones, too.

Imagine a force pulling out on the deck... what is holding the hangers to the ledger?

[Steve Frederickson]

Imagine a force pulling out on the deck... what is holding the hangers to the ledger?

And, what is holding the joists to the hangers? Usually, depending on the hanger, just toenails. That's why I recommend diagonal bracing of the exterior corner posts, running perpendicular to the rear wall of the house (as well as bracing running parallel to the rear wall).

I inspected a deck collapse where all of the joists had pulled out of the joist hangers at the ledger. The ledger was still attached to the house and it looked fine. Luckily, no one was on it. It failed under a snow load.

[Lisa Endza]

CLICK HERE for ledger fastener formula Inspecting a Deck, Illustrated - InterNACHI (http://www.nachi.org/deck-inspections.htm)

[Darren Miller]

The NACHI link is nice but there is some wrong information in it....

Coming soon to a deck near you:

http://www.deckmagazine.com/pdf/2007/0707/0707ledg.pdf

[A.D. Miller]

The NACHI link is nice but there is some wrong information in it....

Coming soon to a deck near you:

http://www.deckmagazine.com/pdf/2007/0707/0707ledg.pdf

DM: Good info. Thanks.

[Lisa Endza]

Inspecting a Deck, Illustrated - InterNACHI (http://www.nachi.org/deck-inspections) updated to include 2007 IRC Supplement reference to hold-down tension devices (2 per deck required) and a new graphic. Thank you gentlemen.

[Jerry Peck]

hold-down tension devices (2 per deck required)


"not less than" two per deck

And don't forget the nailing of the floor decking to those joists at 6" o. c. maximum.

Who is going to add or verify nailing at 6" o. c. for an add on deck?

[Lisa Endza]

And how do you attach them to open web truss joists? I thought you weren't supposed to modify those things.

[Jerry Peck]

And how do you attach them to open web truss joists? I thought you weren't supposed to modify those things.

Before attaching them to truss joists (open web joists) or to I-joists you would need engineering from the truss manufacturer.

[A.D. Miller]

I would like to point out here, for those who may not have noticed, that someone at INACHI is not only listening to the inspectors on this forum, but actually making changes in real time to their training material based upon the good information from here.:D

Try even dreaming about that happening with the ASHI and NAHI groups.:eek:

It is enough to make a man take a long hard look at where he spends his HI organization money. At least, it is for me.:o

[Raymond Wand]

Aren't you a push over! :D The info was wrong to begin with, had they researched it in the first place they wouldn't be needing to update it. :p Besides they don't want the wrong info creating a liability.

[A.D. Miller]

Aren't you a push over! :D The info was wrong to begin with, had they researched it in the first place they wouldn't be needing to update it. :p

RW: At least they had some information on their website, wrong or otherwise. :D

[Lisa Endza]

No, it wasn't wrong. We removed nothing. We just didn't create a graphic for it till today. We are adding ledger to concrete and solid masonry graphics to it this evening. Our graphics are all done in-house. Kenton is working on a section describing how to inspect ledger-to-log home attachments. It will be added next week. Inspecting a Deck, Illustrated - InterNACHI (http://www.nachi.org/deck-inspections.htm) Like codes, it grows.

[Raymond Wand]

A.D.

I don't put any reliance on any association providing with me with a wealth of info that I can find on the net and from people like you and the others.. ;)

[Darren Miller]

There are actually 3 things I see that are either 'completely wrong' or that can be easily mis-understood:

1) one of the first illustrations shows a deck being supported by a 'rail'

2) A post should be 6x6- the code states "wood columns shall be not less than nominal 4x4"

3) Butt joints must be over columns- Actually, if a joint is properly engineered, it doesn't have to have bearing.

4) ledger connections to house shows minimum 5 inches from edge; the requirement is 2 inches, same as top and bottom.


There's nothing worse than thinking you made the right call and someone comes out with documentation that proves otherwise.

[A.D. Miller]

A.D.

I don't put any reliance on any association providing with me with a wealth of info that I can find on the net and from people like you and the others.. ;)

RW: While I certainly agree with the idea that independent research is the key to education, I am also of the opinion that it is the responsibility of professional organizations to provide venues for quality education for their members.

While I think that the NACHI website is poorly designed, it has more usable information on most pages than the ASHI and NAHI websites have in toto.

I am a member of many, many professional organizations other than HI-related. Each of these has a wealth of educational information available for me to avail myself of. And, most have annual membership fees right in line with what the HI groups charge.

Where, oh where, do you suppose my money is being spent?:rolleyes:

[Lisa Endza]

Darren, thank you for your comments.

We added brick face to one side of the deck images so as to make the "house" side and the "outer rail" side more clear without labeling. Then we removed the confusing labeling. Thank you.

The article does not address anything specially "engineered" such as butt joints that can be placed within a girder span without support. However, we adjusted the text to recognize specially engineered butt joints in girder spans. Thank you.


ledger connections to house shows minimum 5 inches from edge; the requirement is 2 inches, same as top and bottom. The 2007 Suppement requirement is actually 2 to 5 inches for the ends of ledger boards. Although some codes permit a large bolt or lag screw to be placed within 2 inches from the end of a ledger board, InterNACHI recommends 5 inches on ledger boards to minimize end splitting (from the load they carry). There are a variety of references on the internet explaining why to try to avoid the very ends of members under load.


A post should be 6x6- the code states "wood columns shall be not less than nominal 4x4"In all but the lowest of decks, InterNACHI recommends 6X6 to account for decay of posts that are in the ground, natural twist of longer posts, and to give some room for notching. Also, read IRC's R407 which states "All deck post sizes shall be 6X6 (nominal) or larger, and the maximum height shall be 14'-0."

Again, thanks for helping.