I have a Adco cover on my class C for the winter. Its ok, but is thin and in some spots the rain gutter is wearing thru it. And i dont like the fact that it isnt completely waterproof. It will shed water , but its like a tent almost. If it gets touched from the underside, it will let water seep in. I will eventually get a COMPLETELY waterproof cover someday. For now, i will put a tarp under it and then the adco cover over that for the winter. Because we get snow up here, and with the cover on, i cant get on the roof to remove it