Post Installing Roof Diaphragm Blocking
Post Installing Roof Diaphragm Blocking
(OP)
I have a contractor that has installed the roof and shingles on a 5 story apartment. However, they forgot to install the diaphragm blocking. Obviously, it's costly to rip the shingles off to be able to get the appropriate nailing through the sheathing into blocking below. Are there any methods of attaching the sheathing to the blocking from the underside?






RE: Post Installing Roof Diaphragm Blocking
RE: Post Installing Roof Diaphragm Blocking
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Post Installing Roof Diaphragm Blocking
KootK - the contractor submitted a request to nail through the underside, which is no good. I agree that screwing through the roofing puts the roof above in jeopardy.
There may be a compromise in terms of finding how much of the roof can go without blocking and the rest of it needs the roof torn up and adequately blocked
RE: Post Installing Roof Diaphragm Blocking
RE: Post Installing Roof Diaphragm Blocking
I believe that, without attaching to the sheathing:
1) You haven't increased the number of fasteners transferring shear from one panel to the next and;
2) You haven't braced the panel edges against shear buckling.
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Post Installing Roof Diaphragm Blocking
Not the best option, but better than nothing.
Mike McCann, PE, SE (WA)
RE: Post Installing Roof Diaphragm Blocking
RE: Post Installing Roof Diaphragm Blocking
RE: Post Installing Roof Diaphragm Blocking
If there is still a problem, I think I would try to get comfortable with gluing the blocking--no screws or nails! I would be afraid that in the process of "trying to get your numbers to work out" you end up creating a bigger problem--a leaky roof.
DaveAtkins
RE: Post Installing Roof Diaphragm Blocking
I like the idea of flat blocking, but like Dave said, a leaky roof using nailing/screws is a bigger concern.
And I'd rather not reduce the design of the building to meet the as-built condition.