[Mike14bumblebee]

Thanks Spike. 2x4 on 16 centres is required by code, I assume 2x6 would just be going over the limit lol. I don't have tons of room to go much bigger. My shelter I had the car in the last couple of years was 20x10. So I no my length of 20' is good and the car is less then 7' wide. So potentially I could fit 2 cars in the 16' width. But I do realize that the 16x20 is outside dimensions and it will be smaller on the inside.