2-post lifts (under 12,000 LB. capacity):
Four (4) inches of concrete at 3000 PSI
12,000 pound two-post lifts (and higher capacity):
Six (6) inches of concrete at 3000 PSI is required.
NO! Our listed concrete requirements are sufficient. But, if it makes you feel better, you may pour the concrete as thick as your pocketbook will allow.
You may install (anchor) your lift (four days) after the concrete has been poured. You must wait a total of seven days before using the lift to its rated capacity.
Drill a test hole and measure the thickness. Most garages will have at least four (4) inches. If you mount the lift and the "anchors" begin to lift out of the concrete over a period of time, you will need to relocate your lift or pour "new concrete pads" under the columns. There is also many types of epoxy concrete adhesives that help anchor your lift in marginal concrete.
The new pad should be at least 4' by 4' and 10" thick. These new concrete pads should have "rebar" installed into the new pour and into the sides of the existing concrete slab.