A portion of my home has plywood as an exterior underlayment, and a portion is "rboard," an insulating material that is essentially hardened styrofoam. I can’t see how when used alone rboard is sturdy enough to create structural integrity. Can it be used by itself or must it be used in conjunction with exterior plywood (for dwelling areas)? Please let me know, and thanks!
R board or *insul board is not a good substitute for plywood or o.s.b.
It has little diaphragm properties ( will not hold framing in place when weight is applied downward to the wall ), therefore builders and remodelers use it only on single story homes and then only between the corners.
I suggest you use 1/2" o.s.b for exterior sheating or 7/16" on all projects, it is currently priced to be comparable to R board or not much higher.
R board is a cheap way to cut costs, plus it burns readily.
Some builders always use it in the gable ends and is somewhat detectable because it is not strong enough to pull all framing in line and keep it there, you see lots of wavy siding up in these gables when this R board or insul board is used.
Any diaprahm wall I have ever seen on drawings is plywood or o.s.b. never R board or insul board.
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That would depend on how the house was framed and what the external treatment of the wall was going to be. I could see a situation with a brick veneer or natural rock exterior where this arrangement would be fine.
References :
R board or *insul board is not a good substitute for plywood or o.s.b.
It has little diaphragm properties ( will not hold framing in place when weight is applied downward to the wall ), therefore builders and remodelers use it only on single story homes and then only between the corners.
I suggest you use 1/2" o.s.b for exterior sheating or 7/16" on all projects, it is currently priced to be comparable to R board or not much higher.
R board is a cheap way to cut costs, plus it burns readily.
Some builders always use it in the gable ends and is somewhat detectable because it is not strong enough to pull all framing in line and keep it there, you see lots of wavy siding up in these gables when this R board or insul board is used.
Any diaprahm wall I have ever seen on drawings is plywood or o.s.b. never R board or insul board.
References :
G.C.