A concrete slab would be good to use. As for the roof, 6'-8' wide, but how long? With the weight of ice and snow I would suggest 2x6 for your framing, due to sagging, as long as you don't go over 10' or so.(not sure of your building codes out there.) 16" on center will be fine. What's going to hold your roof up? Plywood alone is NOT a suitable roof covering. Use 15# felt and a asphalt shingle of some sort. Nails or screws will be fine. I would look into building a real shed around it.
Last edited by Jack of most; 01-21-2009 at 06:50 AM.