Even though plywood is more expensive, and osb stronger, my recommendation for a shed roof is 5/8” or 3/4″ construction-grade exterior rated (cdx) t&g plywood. the higher the slope, the more quickly the snow and rain will be shed, but also the greater the wind force.. Pressure-treated plywood is an exterior-grade plywood that will resist rot and decay for a lifetime. it is the preferred flooring material for an outdoor shed.. Wood shed pressure treated or not. posted by berner, oct 8, 2014 at 7:07 am. if you are building a shed that will last, pressure treated wood is a way to go. i used psi treated posts but the rest are scrap from a lumber yard cull pile and metal roof..
I know you could make this shed much cheaper (probably under $1,000) but i used exterior 3/4 plywood for the floor and 3/4 exterior siding (and pressure treated lumber for the base structure and the wall studs). i also used plywood and architectural shingles for the roof.. The 1/2 in. x 48 in. x 8 ft. cdx pressure-treated pine plywood is a good wood for building barns, playhouses, and sheds. it has been specially treated to help protect it against fungal decay, rot and termites.. That could be your biggest problem in you are using shingles on to low a pitched roof. we used 3/4" pt plywood for sheating on a flat roof in 1982. i recovered the pt plywood in 2002. it has been leaning agianst a tree behind my shop or used as walk boards since then. good stuff, that old cca treated plywood..
