Our company currently uses orientedstrand
board (OSB) for both subflooring
and roof sheathing. Previously we
used 3/4-inch pine plywood on floors
and 3/8-inch pine plywood on roofs (fir
plywood costs too much for our budget).
The switch to OSB saves us
money – almost $1 a sheet – but we
made the switch primarily because we
think that OSB is a better product. In
this case, we're getting better quality
and a lower price.
We think OSB makes a stiffer floor,
so we figure it also makes a stiffer roof.
Just be careful when you buy your OSB
that you're getting rated orientedstrand
board (see "An OSB Primer,"
Spans and Specs
For flooring, we use 23/32-inch