Thread: Ledger Attachment

This is from new construction... I said it's most likely incorrect and would need to be approved by an engineer.

The ledger has several small spacers that place is 1.5" out from the rim joist. Most of the lag bolts are left spanning this gap. I'm not sure what the point of the nuts and washers is. Maybe an attempt to keep the bolts from bending??

Even my caviat of 'most likely' is pretty generous, I'm thinking.

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It's a good idea to space the ledger out slightly, but that takes spacing to a whole new level. I would have written that up as well.

The other crazy thing was that I was only able to identify 3 bolts coming through from in the crawl... meaning that the others (probably 10+) were screws of unknown depth and ended who knows where.

The washers are to stop the nut from eating into the wood as it tightened. This allows the nut to be torqued tighter.

Depending on the construction the 2007 IRC supplement my specify a max of 1/2" between "the face of the face of the ledger board and face of the wall sheathing", see table R502.2.2.1, notes 2 and 8 here:

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

Originally Posted by Michael Thomas

Depending on the construction the 2007 IRC supplement my specify a max of 1/2" between "the face of the face of the ledger board and face of the wall sheathing", see table R502.2.2.1, notes 2 and 8 here:

Michael,

A better statement would be:

2 The maximum gap between the face of the ledger board and face of the wall sheathing shall be
1⁄2".

with the information that the note 2 was relating to:

Joist Span (ft) ------------- 6' and less --- 6'-1" to 8' --- 8'-1" to 10' --- 10'-1" to 12' --- 12'-1" to 14' --- 14'-1" to 16' --- 16'-1" to 18'
Connection Details ---------- On-Center Spacing of Fasteners 4,5
1⁄2" diameter bolt with ------ 36 ------------ 36 ------------- 29 ------------- 24 ---------- 21 ------------ 18 ----------- 16
15⁄32" maximum sheathing and
1⁄2" stacked washers2,8

With the key to that allowance being " 1⁄2" diameter bolt with 15⁄32" maximum sheathing and 1⁄2" stacked washers "

What's with all those holes in the face and edge of that ledger.

Jerry,

What surprised me was the extra 1/2" allowed in note 8 - how much support against shear is supplied (for example) by gypsum board?

What's with all those holes in the face and edge of that ledger.

Jerry,

That's what our pressure treated wood looks like. Look at the joists and you will see the same thing.

Originally Posted by Jerry Peck

What's with all those holes in the face and edge of that ledger.

No problem with the holes. Its just pine wood boring beetles eating the soft wood getting a snack

Originally Posted by Michael Thomas

What surprised me was the extra 1/2" allowed in note 8 - how much support against shear is supplied (for example) by gypsum board?

Michael,

That was my first thought too, then I realized it is not just an "extra 1/2 inch", it is a totally different setup.

In note 2, the 1/2" can be made up with "stacked washers" - unfortunately, no mention of their outside diameter was made, I would think they would want fender washer sized washers, not regular small outside diameter washers, but, that was not mentioned (or I've missed it).

However, in note 8, there is no "cantilevering" as such (in note 2 the bolts are are cantilevered out that 1/2", with the stacked washers supporting the "cantilevered" distance) as the exterior sheathing is required to be full thickness, up to the maximum thickness of 1". That means that the ledger is pulled snug to the sheathing with friction between the sheathing and the ledger being used to distribute the load to the sheathing above and below (unlike a "cantilevered" bolt, which is trying to shear itself off or 'bend' the bolt).

I guess until the gypsum is either crushed (easy to do with a washer and a nut, but much harder to do with a ledger distributing the load of that washer and nut) or is wet (and it is assumed that the gypsum sheathing will not get wet, after all, it is supposed to be properly flashed, and the wall above is properly weatherproofed (in whatever manner is appropriate for the siding/veneer used). Thus, dry gypsum will support quite a bit when the load is placed over a large enough area. At least that was my thoughts on it.

However, it also includes "foam" sheathing, is that even as strong as gypsum? If so, then the above would apply to it. If not, I'm out of ideas.