Every manufacture seems to have a slightly different spec on slab thickness. Many say 4" is good (Rotary 4 1/4" min.), some want 6" and Mohawk (the absolute Cadillac) requires 12". Best is to go to the web site for the lift you're considering and see what they require.
My slab was 6", however I had a crack exactly in the way. So, rented a walk behind concrete saw with water cooling, bought a $100 diamond blade and cut out a 4'x15' section.
When I got the old concrete out, I found a tree root under the crack...so much for the shade trees, I've since cut 3.
Dug down a little deeper, put down #4 rebar on 12" centers on little spacers and dug under the existing slab 6" then had 8" of 5k concrete pored.
I sprayed water on the concrete and kept it covered with plastic and wet for a 5 days and didn't install the lift for 4 weeks.
Lift is anchored with 3/4"x10" redhead style anchor bolts torqued to 150 lbs.
Well shoot, Grigg is quicker on the trigger than me.
Last edited by moparguy; 12/23/2016 1:00 AM.
