Had to redo my entire bathroom floor after 3 years because I skipped the underlayment

I used to think Schluter membrane was just an upcharge for jobs until my grout lines started cracking (even with the good stuff from Home Depot). Has anyone else regretted skipping a vapor barrier or waterproofing layer in Edmonton's freeze-thaw climate?

2 comments

2 Comments

the_leo4d ago

I was reading a thread on a construction forum the other day where a guy from Saskatoon swore he'd never skip a vapor barrier again after his whole tile job lifted up like a rug in the winter. Edmonton's freeze-thaw cycle is brutal for that stuff, moisture gets trapped underneath and expands when it freezes, then your grout goes to pieces. I saw a video from a local tile inspector where he said the number one mistake people make around here is thinking one layer of waterproofing is enough, especially with temperature swings like ours. Your story just confirms that skipping the underlayment was probably a costly lesson, but at least you caught it before more damage showed up.

margaret_lane4d agoTop Commenter

My own bathroom tile job from two years ago would probably make that inspector cry, so I feel this deep in my wallet. I used one of those all-in-one waterproofing membranes and thought I was being so clever, but four months later I had a grout line that looked like a little canyon forming right near the shower curb. Turns out the temperature difference between the warm shower floor and the cold subfloor underneath can pull moisture right through a single layer if the install isn't perfect. My dad still jokes that I built a swimming pool inside my wall instead of a shower, which is pretty accurate. Did you end up going with a full vapor barrier and a separate waterproofing layer on yours, or did you find a system that works for our climate?