That glue down job last month on Maple Street taught me a hard lesson about subfloor prep

Walked into a house on Maple Street in Cleveland last month. Homeowner said the old carpet was pulling up at the seams. I figured I'd just tear it out and throw down some new glue down. Three days later I was pulling up half the job because the moisture in the concrete slab wasn't tested. The sealer I used didn't stick right and bubbles showed up everywhere. Has anyone else run into this with older concrete slabs that weren't sealed right from the start?

2 comments

2 Comments

faithcampbell14d ago

Our shop in Akron had a slab from 1958 that laughed at two different moisture barriers. Ended up using a gypsum-based underlayment from Ardex that cost about $0.80 a square foot but saved my back. That old concrete was basically a sponge sucking up humidity from the ground. Bet that Maple Street pour has the same issue if the vapor retarder broke down over the decades. A cheap moisture meter might have caught it before you pulled that first box of planks out of the truck.

drew_reed6214d ago

Yeah, that "sponge sucking up humidity" hit home. I had a similar nightmare with a slab in a 1960s house. Ended up using a self-leveling compound that was paintable and vapor-proof, some Mapei stuff I think. It was around the same price as your Ardex, maybe a bit less, but it leveled the floor perfect so the planks didn't buckle. The moisture meter is key though, I bought one after that job and it's saved me from pulling my hair out on every old concrete pour since.