There is a Direct Lift dealer about 1/2 hour drive from me. Can anyone tell me how good these lifts are? I'm thinking of a 2 post. Installation instructions call for 3000 psi concrete of min 4" thick. How do I know if my slab meets this criteria? I know that it was reinforced with wire. Most 4" slabs use a 2 x 4 for a guide which is actually 3 1/2 " thick.
