This is a 12x16 shed built out of rough cut 2x4s about 25 years ago. The inside is rather solid the foundation is sinking and not so solid. The front is lower than the back my plan for now was to lift up the front corners and put a 12' 4x4 across the front . Here are pics as well . I was going to use a jack with wood support to do this any thoughts or nay sayers as I have leveled new sheds but never an old one or one this large. My concern is while the top is solid the bottom is soft and lifting he corner the needed 5-6" might crack something or not?