Curved plywood sill/top plates

[swooop]

Working on a 20'x40' oval (in plan) structure. The framer used 1 1/8" rated plywood for the curved sill plate, and double 1 1/8" for the top plates. Is this typical practice for curved situations? This is the first curved structure I have worked on.

Also, how are curved shear walls dealt with? They cut a 1/8" deep vertical cut all the way up the wall every 4 or 5 inches O.C. so they could bend the plywood to fit the wall. Obviously, this is no good. What is the norm? What do you suggest for a fix?

Thanks!

 

[UcfSE]

Using plywood to cut out curved plates is fairly normal in my area (FL). I can't vouch for the thickness. I would have asked for 3/4-plywood built-up to 1.5-inch and 3-inch thicknesses.

Where the plywood is cut, can you use the thickness of the plywood minus the cut depth for your "effective" thickness of shearwall?

 

[swooop]

I actually detailed 2-2x6 top plate and 2x6 sole plate, contractor chose to ignore that.

The effective thickness would be slightly less than 1/4".
The shear in the walls is minor, and I'm not worried about it, but I would like to have at least the 3/8" thickness. I think I will have them put a 1/4" or a notched 3/8" panel on the outside of the ex. panel. That should take care of it.

 

[UcfSE]

The thing you have to watch with the plywood is the bending strength is less than you would have from the sawn lumber you called for. The bearing may also be smaller, I'm not sure. If you don't need that strength then there isn't much difference. Most of the time you probably won't. The other is to make sure you have the pressure-treated lumber against the concrete if your code requires it.

 

[DaveAtkins]

Your contractor did everything I would have expected. The only way to make curved sill and top plates is to use plywood. How would you curve a 2 X 6?

For the sheathing, I have usually seen 1/4" plywood used, since it is flexible enough to curve.

DaveAtkins