Pour an overlay concrete floor over a sloped garage floor.

Q. How to best pour a level concrete floor over the existing sloped concrete floor for a garage conversion into living space.

The thickness of the new pour starts at 2 1/2 inches and ends at the end of the existing garage at 5 inches.
The amount volume of pour is just about 5 cubic yards.
The wall partitions are already up. Wood framing.
Would greatly appreciate some expert guidance.
Thank you,

A. We do concrete overlays like this all the time. All you have to do is install a layer of Typar on top of the old slab. You don't want the two concrete slabs to bond to each other, you want them to be able to move independently of each other. This minimizes cracking.

Use a 3000 psi 3/8 peastone concrete mix from a redi-mix concrete plant. Use a laser level to mark your grades on your interior and exterior walls. Pour the new floor over the old floor just as you would any new concrete floor.

Use an isolation strip between the walls and new concrete to keep the concrete from coming into contact with the wood.