Bathroom & Wet Area Seepage Solutions

Seepage into the bedroom wall next to a bathroom, a damp ceiling under an upstairs toilet, tiles that never quite dry out — wet-area leakage shows up one room away from its source. The fix is a flexible, waterproof barrier in the sunk slab and wet zone.

These coatings are formulated for bathrooms, toilets, sunk slabs and utility areas — flexible cementitious systems that bond to concrete, brick and mortar and accommodate minor movement.

Renovating or building new? Add an integral admixture to the plaster itself. Estimate quantities with the calculator or send a photo of the problem to our expert on WhatsApp from the Monsoon Ready page.

How to Fix Bathroom Wall Leakage Permanently

Bathroom wall leakage into adjacent rooms is almost always caused by failed or missing waterproofing in the sunk slab (the recessed concrete tray beneath bathroom tiles). The permanent fix requires waterproofing this sunk slab from the positive side with a flexible cementitious coating like SikaTop 107 Seal Plus or BS MoistureZero before tiling. The coating must turn up the walls to at least 150 mm above the finished floor level (300 mm in the shower zone). For existing bathrooms, injection grouting from below can reduce but rarely eliminates the problem. In most cases, re-doing the sunk slab waterproofing during renovation is the only lasting solution.

Which Waterproofing Coating Is Best for Bathroom Sunk Slabs?

Two-component flexible cementitious coatings are the standard choice for bathroom sunk slabs. SikaTop 107 Seal Plus (Rs 6,800 for 25 Kg) provides excellent adhesion to concrete and accommodates minor structural movement without cracking. BS MoistureZero (from Rs 375 per Kg) is a more economical option using acrylic polymer modified cement slurry. Both are water-based, low-odour, and safe for indoor application. Apply in two coats at right angles to each other for complete coverage.