Assembled on a concrete slab,summer of 2014. It has never leaked. This is the first winter of use and I am having difficulty with closing the double door due to the top frame having dropped slightly. Probably due to about 2" of snow and ice. I will have to construct an extra metal reinforcement truss for above the door to resolve this problem. The plastic roof panels are also slightly rounded downwards between the trusses. Assembly was a bit time consuming,but that should be expected. I strongly recommend 2 people to assemble.On the inside I have added fluorescent lights and a receptacle and outside I also have a receptacle and a small yard floodlight over the door. This is quite an attractive looking medium size storage shed.