Metal threshold angles - One of the best things you can do for your shed is to protect the shed floor where your shed doors are located! Rarely do I see homeowners doing this after building a shed. The cost is so minimal and the benefit so great. All you have to do is buy a length of aluminum angle iron, preferably about 2" on each side, cut it to length, and screw it down to your floor. Don't go with really thick stuff, you just need about 1/8" thick aluminum.