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RE: Wood Shear Wall Nailing[Subject Prev][Subject Next][Thread Prev][Thread Next]
- To: <seaint(--nospam--at)seaint.org>
- Subject: RE: Wood Shear Wall Nailing
- From: "Dennis Wish" <dennis.wish(--nospam--at)verizon.net>
- Date: Tue, 29 Jul 2008 06:35:37 -0700
This is about a week late, but I thought I would throw my two cents in. Back in the 80’s when we were doing seismic retrofits we found that in full size lumber 10d Common nails could split a full 2x member. The problem was the placement of the nail on lapped sheathing or and the clearance to the edge of the member. Common nails have a larger shank diameter and larger head. When dealing with shear, the depth of embedment was not as much an issue as the shank diameter since even Simpson has an N10 nail in various lengths that conform to the code required shear values on structural panels.
It became my practice to follow Gerard’s standard of specifying only 8d Common nails. At one point I even included a full size detail of all of the common nail sizes so the contractor could place a nail up to the detail to assure that the head and shank diameter matched the detail if he had any questions. The problem, of course, was that the framers would call in a sub to nail up the panels and these guys would get paid by the board feet or panels nailed. They always seemed to believe that it was best to over-nail rather than to take the time to verify spacing and it became evident that with 10d common nails, they would invariably split a member or nail them too close. The other issue, of course, was the use of a four ply 3/8” plywood panel instead of a 5-ply 15/32” or ½” panel.
To make it short, I decided to rely on my specifications and details. If they got it wrong and I spotted it, they had to correct it. I was spending so much time checking for crushed ply’s, sinkers vs. commons and all of the other problems associated with observation that it would defeat the purpose over the long run. When brought to the attention of the city in an observation report or to the GC who relied on his framer (uncertified guy with a power nailer and an attitude that anything he nailed lasted longer than the Pyramids), I ended up getting into more fights than it was worth. If it failed or performed poorly, at least I spec’d it out properly and attempted to correct it. In more than one case I charged to redesign and never got paid – only got threats from owners who understood his contractor rather than the code or his technical speaking engineer.
I think we do the best we can, but the reality is that when conventional construction (IRC or prescriptive) is added to the argument, the issue becomes the bottom line of the code – will it hold up well enough to protect lives and get people safely out? Beyond that we hope for good and competent contractors who know how to read our specifications and details, but as I get older and crankier I get the feeling that we are losing the war.
8d Common nails as per my shear wall schedule – them’s the standard on my drawings. No 10d’s (especially on KD Lumber) and even more so on retrofits that had already been nailed once. If I keep it at 8d Common with 5-ply panels then I can allow some leeway in the quality control issues.
FWIW, I always use 8d nails for
shearwalls without too many problems. Most of the phone calls I get are in
regard to Sill Nailing getting confused with "Shear Nailing"
On Tue, Jul 22, 2008 at 12:59 PM, Drew Morris <dmorris(--nospam--at)bbfm.com> wrote:
Michel Blangy wrote:
I am curious as to whether your wood shear wall schedules
are based on 8d,
No, although I prefer to use 8d on the walls and 10d on the
roof sheathing. What concerns me
- RE: Wood Shear Wall Nailing
- From: Michel Blangy
- RE: Wood Shear Wall Nailing
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