The guy comes out and did all the work on premises, it is not prefab. It's excellent material and excellently done. You can get any size, you can have a loft, they will literally make it any way you want it. Very reasonably priced, mine cost me a little less than $2900, but I do have a loft and a lot of extras. They do it in one day. He comes out in the morning and works until, he gets it done. Absolutely, one of the best things, I ever did.