Looking to put in Laminate flooring and seeing if my plan is ok or if it needs some correction.
This is a half basement on grade, with about 4 feet underground on one side and walk out level on the other side. Slab with stub wall construction. We had interior ground tile installed when we first moved in per inspection showing that there was water intrusion (it may have been a ploy for business, but we also dealt with other things that needed to get away away from the foundation. In the PNW and out slab stays dry even after weeks of winter rain.
late 1970s housing (lucky no lead/asbestos) with not so great insulation and none on the stub walls. When they ripped up wall I placed XPS between the studs on one side and completely sealed the other wall with XPS and seal tape that I reframed (non load bearing and old wall came out of existing frame) .
I removed the existing flooring and thinset and cut the old drywall that made contact with the cement, it severely reduced the slight musty smell of the room.
I know the slab in slightly unlevel, and this is worst at where concrete that replaced the ground tile is. The worst place is shown where variation goes up to 1-1/4" max from the low spot on the slab (0"). The concrete where the ground tile was installed is at least 3" thick. Framing is directly on concrete using ground contact wood.
Flooring Plan I am finally getting around to replacing the flooring. The old flooring was carpet on top of old ceramic tile. I wanted carpet (its warmer) but the other half wants laminate. I know I have to keep it flat within specs of the flooring. The plan is to.
- grind down the cement that was replaced with the ground tile to 1/4 height above the low spot (or locally where the old slab height is if greater).
- Use leveling compound to fill the low spot 1/4 inch and feather the edges to get the slab flat enough for the laminate.
- Use a 6-10 mil underlayment to seal the concrete.
- Use a 12 mm laminate to keep even with the existing tile in the hallway. I am trying to keep the flattest transition and the slab height is about 1/4" higher than the low spot here.
I really wish the slab was insulated and wanted the extra insulation of the carpet. Is there any solution to help besides putting in block insulation and new subfloor? I was thinking about putting in 1/4 XPS instead of the self leveling compound but that is probably a bad idea for floor flexing. Will probably end up covering most of the area (non traffic portion) with wool rugs. I am also planning on installing 2 inches of XPS foam with borate to the exterior stub wall with an insect break to 2" under in the future
Concerned about feathering edges of leveling compound, is there a better solution for this?
Cutting into ground tile concrete too deep. I know its at least 3 inches in some places, but worried that cutting 3/4" in the worst spot (in that corner) may compromise it.