Waterproofing might sound like a one-and-done job. But skip the right steps, and you’ll be scrubbing stains, replacing plywood, or worse—redoing the entire bathroom. Here are the top 7 waterproofing blunders to dodge during your reno:
1. Skimping on Surface Prep
You wouldn’t paint over dirt, so why waterproof a grubby surface? Not cleaning or leveling properly is a recipe for poor adhesion—which practically invites leaks. Ensure surfaces are clean, dry, and free of loose debris before applying any membrane.
2. Using the Wrong Product for the Job
Your bathroom needs a different solution than your balcony or rooftop. Not all membranes are the same—use exterior-grade, UV-resistant ones for balconies and proper sheet or cementitious types for wet areas to avoid one-size-fits-none failures.
3. Leaving Corners, Joints & Penetrations Unprotected
Corners and pipe entries are the most vulnerable spots. Skip angle fillets or sealing and you’re effectively doing half the job. Reinforce these areas properly—otherwise, cracks are just waiting to unleash water damage.
4. Forgetting Drainage & Sloping
Flat surfaces without slope make your waterproofing immortalize standing water. Without proper drainage, even the best system can collapse under hydrostatic pressure. Always factor slope and flow into your design.
5. Ignoring Curing Time & Manufacturer Guidelines
Rushing the job? Think again. Waterproofing membranes need time to cure—and each product has its own rulebook. Applying coats too fast or too thick, or in the wrong weather, weakens the entire system.
6. Relying on Sealant as a Quick Fix
A redditor famously shared how sealant was recommended for fixing failed waterproofing—even though the timber studs were rotting. The real fix? Strip out, re-waterproof from scratch, or say “hello” to more repairs in two years.
“That sealant fix will last about a year before it fails… tiles must come off, waterproofing must be re-applied.” — Redditor note on failed bathroom waterproof repair. Reddit
7. Skipping Testing (Ponding Test)
Don’t trust the waterproof shell until you’ve tested it. A ponding test—letting water sit for a while—spots leaks before tiles go on. Skip it at your peril, because fixing post-tiling is a disaster.
Final Word by Chemind Industries
Waterproofing is not something to wing. Avoid these top mistakes—even small shortcuts can lead to big, costly complications later on. Want to shield your renovation from water woes? Reach out to our specialist, we got your back.