
Originally Posted by
632 Regal
at least think about dumping a couple inches of perlite under the (floor) concrete. You can get huge bags on 'tha bay' for cheap and the difference will be amazing. love them ratwalls man, just like a garage I built years ago, so thick the floor will never move or crack. If you do the perlite thing make sure to run a sprinkler over it for 24 hours, running a sprinkler on the freshly hardened concrete for 2 weeks will help it dry even harder.... learned this stuff from an old Italian mason, RIP.
So what's Perlite and how does it help? I see some on ebay as you mentioned and it says 'product made for mixing in concrete to make whatever you’re doing lighter in weight'. But not sure how that would help? Why do you need a lighter concrete floor? And were you saying to add 2 inches underneath the concrete? Or mixing it in with the first 2 inches of concrete? We may end up building some garage space in the next house so it would be nice to understand what I don't understand. 
Also, how often during the 2 weeks should the concrete be watered? Once a day for a few minutes?
Thanks.
'94 540i
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