Warning: subfloor moisture meter gave me a false reading last Tuesday

I was laying glue-down vinyl plank in a basement job near Columbus last Tuesday. Checked the slab with my pinless meter, got readings around 3%, thought we were good to go. Laid about 300 square feet before I noticed the glue wasn't tacking up right in a corner. Pulled out my old calcium chloride kit, ran a quick test, and that corner was pushing 12% moisture. Had to tear up everything I'd done, rent a big dehumidifier, and wait three extra days. My meter was flat-out wrong on that concrete because the surface was sealed with something I couldn't see. Anybody else ever get burned by a moisture meter lying to you?

3 comments

3 Comments

thomasb4117d ago

Might've been an old densifier that left a thin film.

rose_clark8117d ago

What kind of sealer was on that slab?

nathan_kim16d ago

You ever notice how every floor problem comes back to what someone put on it years ago? Tacky sealers, cheap coatings, guys just grabbing whatever from the hardware store. No one thinks about long term. Then you're stuck grinding it off later. It's like a hidden time capsule nobody asked for.