Wow, same decorater did my garage! I priced out sheetrock and OSB last fall, OSB was cheaper, checked with city hall, the garage is detached, everything was within code. When I finish the ceiling it'll be 5/8 sheetrock.
There more than likely will be gasses coming off the walls, but I drink beer out there and on occassion there are gases coming out of me, don't know which is more toxic!



It is OSB, and it really is more expensive than drywall! It generally is fire treated, and is frequently used as roof sheathing and even wall sheathing, over which a finish surface like lath and stucco, lap siding or brick is placed. It is very strong, and is a "green" product, if you care about that kind of stuff. It does not paint well, for obvious reasons. I see it in interior garage walls and workshops a lot.
I asked "Bob" the County building inspector if this was a problem or a code violation and he said: "No, not at all."