I have had 2ea metal covers installed over the years. First was for a car cover that can fit 3 cars wide (open span). The second cover was for my travel trailers. Had a bumper pull and 5th wheel at the time. Now just have the 5th wheel and the extra room is nice to have. While home I can use the extra room under the cover to bar-b-que, etc. I have been very pleased with both covers and they have held up well. Both were installed on just a gravel pad. Both have open sides although on the RV cover I had one panel along the side at the top. Both were installed on-site within a few hours.