Do I need a waterproof membrane under tile or a toilet flange?
Waterproof membranes prevent trapped moisture and water accumulation beneath cement board, tile, and toilet flanges. Without proper waterproofing, underlying layers can become wet, loose, or crack and shift over time.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Relying on conflicting advice from different sources or installing cement board and tile without extra liquid waterproofing.
- 2pulling out the tiles and considering patching or thinsetting over the loose membrane
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“Should I add a waterproof membrane liquid (like Aqua defense) over plywood?”source ↗
Ioiwin · r/HomeMaintenance · 1 upvotes
Where this came up
People with this problem also raised
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- 2Can you use fiberglass insulation in a basement after flooding?
- 2Can I insulate and finish basement walls if they get damp?
- 2How do I know which sealant to use for a bathroom sink?