How long does concrete need to cure before applying self leveling compound?

Question

How long after pouring a thin layer of concrete (sand topping between .5 - 2" depth) should I wait before leveling with self-leveling compound?

I'm mostly concerned that it should be done shrinking/altering shape more than it reaching some sort of maximum strength. This is an interior floor where I'm adding more concrete on top of an existing slab so it's going on a solid base and not supporting weights like cars.

Background: I have a large room with concrete floor that had a lot of low spots. I'm pouring concrete where the dips are deep enough then will finish with SLC. My concrete skills are too weak to just do concrete well enough for me to trust not needing to then level. It's excess work, but saving thousands vs. doing just SLC.

Answer 1

You still need to follow the instructions for the SLC - most (IIRC) say 30 days minimum cure (for the underlying concrete.)

Be sure to keep it damp so it can actually cure. If it dries out, it stops curing, and that's a very likely thing with a thin pour over an existing slab that will want to suck water out of it.