I have a 1944 detached garage. Its 20X20 and sits on a concrete slab. The roof has sunk down a little over the years, and the walls are rotted at the ground level. I would like to put a cinderblock foudation around the base, put 2x6 joist in to straighten the roof, and jack up the roof 2'. I'm having trouble with the last part- I know it can be done, but what is the safest and least expensive way to do this? I will have 9 interrier 2x6 X 20 joist installed already, I have about 12 12' 4x4s to help stabalize. Trailer jacks, hydrolics? please help>>>>