I am in the process of tearing out the spare bedroom down to the studs. When I rebuild out the room I want to hang ½â€ plywood as a shear wall – due to the fact that I live slightly north of San Francisco. When I hang the plywood what orientation does it get hung? Also, when installing the screws, what is the minimum distance do I need to maintain between them? <!—-><!—-> <!—->
“Projects beget projects and projects beget the need to buy new tools and that is what the cycle of life is all about.”
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The need to install a shearwall is a function of anticipated stresses and the nailing schedule is, in my experience, specified by an engineer.
Orientation of the plywood, according to the American Plywood Assn. (APA), can be either vertically or horizontally, but, IMO, installing horizontally provides more strength when the courses are offset, spreading the strength across the stud layout.
I live in a seismic and wind load area similar to yours and have installed a lot of shearwalls and the nail spacing has varied from 2 inches to 6 inches depending on location of a particular wall and it's orientation to the anticipated stresses.
The last house I built required every wall in the house be sheared on both sides (a real PITA, requiring extra work with utilities and custom door and window jams).
If I read your post correctly, you are planning to use screws....waste of time and money, IMO. A shearwall is designed to resist shear forces where nails perform very well and are much less expensive and much faster to install.
And your building inspector may, like the one here, require that the nail heads lay flush with the plywood surface. If that's your situation, you're best served with a framing gun with a flush head adjustment on the nose of the gun.
If you do hang it horizontally you must use blocking . The perimeter of the plywood provides the majority of shear resistance.
Blocking is not necessarily required on horizontal application. Depends on job-specific engineered specs. I've rarely seen blocking required, with the exception of fire blocking, and I've built numerous houses and additions with engineered shear walls.
I just did this last year.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
I don't feel it's healthy to keep your faults bottled up inside me.
Here is something that might help:
It shows common mistakes, and how it should be done.
Unless your house is ancient, you probably have some extra support, like let in diagonals. Unless you are adding an extra story, everything you do here is just icing on the cake. No extra engineering needed. Don't forget about added anchoring of the base plate to the foundation. Cali even has a guide for general recomendations for people like us who add on after the fact, you can download it somewhere.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
I don't feel it's healthy to keep your faults bottled up inside me.
Thanks again Paul!
Our home is a 1960's ranch style.
Just I thought that the OSB would get hung vertically instead of horizontally like drywall. I actually like the idea of using screws as they would be considerably less likely to work themselves out.
Another question, when it comes time to hang the drywall do you just screw into the OSB field so not to hit the screws connecting the OSB to the studs?
Thanks again sir!!
"Projects beget projects and projects beget the need to buy new tools and that is what the cycle of life is all about."
The great thing about sheathing the inside is that you can put the screws ANYWHERE! There is always something for the screws to bite into - just make sure the wiring is held back! Just make sure your vertical drywall seams are only in the corners. If you must have a seam on the wall, look at a product called the "Butt Taper" - it bevels down the edge on a butt seam so you can just mud it flat without having to dink with shims.The Senco screws will hold just fine, don't let anyone tell you otherwise.Here is a pic of my walls. As I put the drywall up, I used subfloor adhesive too.Rebuilding my home in Cypress, CAAlso a CRX fanatic!
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