Bathroom Waterproofing

Bathroom leaks are the most disputed repairs in any Pune apartment building, because the damage appears in one flat and the cause sits in another. The ceiling stain belongs to the flat below; the sunk slab causing it belongs to the flat above. Leakproofs by Betterwork treats bathrooms across Pune and Pimpri-Chinchwad, and the first job is almost always establishing which of four very different problems you actually have.

Four causes that look identical from below

• Failed waterproofing in the sunk slab. Water from the floor and shower area soaks the fill in the sunk portion, saturates it permanently, and finds a path through the structural slab.
• A leaking supply line. A pressurised pipe leaking inside the wall or the sunk portion. Wets continuously, including when nobody is using the bathroom.
• A leaking waste or trap connection. Wets only during and shortly after use.
• Condensation. An unventilated bathroom in a Pune monsoon runs at high humidity, and moisture condenses on cold surfaces. Looks like a leak, is not one.

The distinction decides who pays and who does the work. A supply-line leak needs a plumber, not waterproofing — and applying a membrane over it changes nothing while costing a great deal. We run the diagnosis before quoting: isolate the supply and watch whether wetting continues, use the bathroom normally and watch whether it worsens, and thermally scan the slab from below. If the answer is the plumber, we will tell you.

Can it be fixed without breaking the tiles?

This is the first question every customer asks, and the honest answer is: sometimes.

Yes, sometimes — where the leak is at a specific joint or penetration, injection grouting from below or above can seal the path without demolition. Where the failure is at the floor–wall junction only, a targeted repair may hold. Where the tiles themselves are sound and well bonded, a transparent or thin-film system applied over the existing tiles can work, provided the grout lines are made good first.

No, sometimes — where the fill in the sunk portion is fully saturated, no surface treatment will help. Wet fill holds water indefinitely and keeps feeding the slab. That has to come out. Where tiles are drummy or the floor has no fall to the drain, the same applies. A contractor who promises a guaranteed no-demolition fix on a saturated sunk slab is promising something they cannot deliver. Our note on repair without breaking tiles sets out exactly which cases fall each way.

Doing it properly when the floor does come up

A full bathroom treatment is a sequence, and skipping any step is why the second attempt fails as fast as the first:

1. Remove tiles and excavate the saturated fill down to the structural slab.
2. Let the slab dry — this genuinely takes days, and it is where schedules get compressed and jobs get ruined.
3. Repair cracks and honeycombing; form a coved fillet at every floor–wall junction.
4. Treat all pipe penetrations individually around the puddle flanges.
5. Apply the membrane to the floor and turn it up the walls — at least 300 mm generally, and full height in the shower area.
6. Pond-test before anything goes back on top. Plug the drain, fill with water, hold for 24 hours, inspect the ceiling below.
7. Reinstate with lightweight fill laid to fall, screed, and tile with the correct adhesive and grout.

Step 6 is the one that gets skipped under time pressure and it is the only step that proves the work. We do not tile over an untested membrane.

The junction and the threshold

Bathrooms leak at edges, not in the middle of the floor. The floor–wall junction, the shower corner, the threshold into the bedroom, and every pipe penetration are where treatment succeeds or fails. The threshold matters more than people expect — a bathroom with no upstand at the door lets water track straight out under the frame into the adjoining room, which then reads as a bedroom dampness problem.

Grout, adhesive and the slow leak

Cementitious grout is porous. Over years, water passes through grout lines and through failed silicone at the corners, and reaches the membrane below continuously. Where the waterproofing is sound this is harmless; where it is marginal, this is the mechanism of a slow failure. In a shower area epoxy grout is worth the extra cost, and internal corners should be a flexible sealant rather than rigid grout.

Societies, hotels and hospitals

In a housing society the sunk slab is normally the upper flat owner’s responsibility while the ceiling finish below is the lower owner’s — agree that split in writing before work starts, because retro-fitting the agreement is where months are lost. In hotels the constraint is rooms out of service, so bathrooms are done in blocks against occupancy. In hospitals, low-odour systems and dust containment are mandatory rather than preferred.

Cost, and what is warranted

Bathroom treatment in Pune typically runs ₹12,000–40,000 per bathroom for a full sunk-slab job, depending on size, how much fill has to come out and the finish reinstated. Injection-only repairs are priced per point and are far cheaper where the diagnosis supports them.

Leakproofs by Betterwork pond-tests every completed bathroom in front of you before the warranty document is issued. Eligible completed work carries a written ten-year warranty on the treated area, with exclusions stated on the estimate before you approve it.