My laundry room flooded due to an exterior leak and I had to pull up the vinyl. Under it I found up to 1.25" of wet, mildewed, compromised, putty-like SLC. Below it is another layer of vinyl with the top layer removed that was glued to the slab. It would seem that the builder tried to get away with with a floor that sloped 1.25" over an 11' run, got called out on it, pulled off the wear layer of the vinyl, leveled the floor and put new vinyl on top.
Because the SLC was waterlogged for who-knows-how long, it was totally compromised and I had to tear it out. I am getting ready to tile my laundry room and need to level the floor again. I have two concerns - a 1.25" thick pour of SLC and that I will need about 8-9 not-so-cheap bags of it.
So far I've removed as much of the bottom layer of adhesive as I could and etched the slab where the etch was able to get to it. Instead of using all SLC, can I build up the really low areas with backer board thinsetted to the slab, then finish the last 0.25" or so with SLC?