Adding a lean to onto a shed involves leveling the earth where the lean to will go and setting posts that will be locked in place with concrete. then, boards, called nailers, are attached horizontally across the posts, and one is added just below the roof of the existing shed.. Storing stuff in a lean to shed: the lean to shed is the perfect solution for storing things. it is simple to build and very functional. the single plane sloping roof allows you to build next to a fence and have the roof line at the top of the fence level or next to your house and have the entire roof sloping away from the house keeping moisture away from the house.. This step by step diy article is about how to build a roof for a 12
