Leveling an Existing Slab Foundation
I will be installing some rigid foam and two layers of plywood over an existing concrete slab to create a wood floor.
I know this subject has been covered at length here, but I am hoping to get one more knock on the head from the GBAers with a particular detail, which is the leveling of the slab (also covered at length here, I know).
It’s a garage slab, good shape, but pitched to drain. (It’s all insulated around the exterior of the slab now, 4′ down into the earth from the sill plate and the surrounding earth has proper drainage pitch).
I’ve got about 3 inches +/- to make up over a 20’x28′ space (550 sq. ft.)
The obvious thing is self leveler. But alas contractors are booked and I fear the stuff. There seems to be quite a few horror stories on botched jobs and you have to work quick. I’m not sure I can get enough hands to make it happen this fall. And it sounds stressful.
Hence I am considering stone dust or similar to level. I have extensive experience leveling the stuff for ADA trails. Obviously where it is laid thin it will not compact well. But can I get away with this if I work carefully placing the foam over it as I go. Does anyone see potential issues with long-term movement of this shim layer of stone dust? Other issues?
Thanks for any thoughts.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part