Roof Waterproofing

“Roof” and “terrace” get used interchangeably in Pune, but they are different jobs. A terrace is a flat, accessible slab you can walk on and pond water on. A roof may be pitched and tiled, a profiled metal sheet over a shed, or a flat RCC slab nobody ever visits. The roof type — not the leak — decides the system. Leakproofs by Betterwork surveys the roof construction first, because a specification that is right for one of these is wrong for the other two.

Sloped and tiled roofs

A pitched roof sheds water by geometry rather than by membrane, so it rarely fails across the field. It fails where the geometry is interrupted: at valleys where two slopes meet, at the ridge, around chimneys and vent pipes, at the eaves where water overshoots a blocked gutter, and wherever a tile has slipped or cracked.

The right response is usually repair and re-detailing, not coating. Coating a tiled roof end to end is a common upsell that traps moisture under the tiles and does nothing about the valley that was actually leaking. What genuinely helps: re-bedding ridge tiles, replacing cracked units, lining valleys, clearing and re-falling gutters, and sealing around penetrations. Where the underlay beneath the tiles has perished — common on older Pune bungalows — the honest answer is a strip and re-lay, and we will say so rather than sell a coating that buys one season.

Metal sheet roofs

Profiled sheeting almost never leaks through the sheet. It leaks at fixings and joints:

• Fasteners. Screw washers perish under UV; the screw hole then becomes a direct path. On a roof of any age, replacing fasteners fixes more leaks than anything else.
• End and side laps. Capillary action pulls water uphill through a lap that has lost its seal.
• Ridge, valley and gutter lines. Internal box gutters are the worst offenders and overflow inward during heavy rain.
• Skylight and service penetrations.

Sheet metal also moves substantially with temperature — a long run expands and contracts every day in a Pune summer — so any rigid treatment applied across a lap cracks within a season. Detail bands must be flexible. See metal sheds and RCC roofs compared.

Flat RCC roofs that are not terraces

A flat concrete roof with no access is treated much like a terrace but with two differences that work in your favour: no foot traffic, so the system does not need to be trafficable, and usually no tanks or planters, so there are far fewer penetrations. That often allows a thinner, cheaper specification than the same area would need as a usable terrace.

What still applies is falls and outlets. A roof that ponds will fail early whatever is applied to it. If the slab has no fall, a screed is needed before waterproofing — and that changes the price. Our detailed treatment of slab behaviour is in terrace waterproofing, which covers the accessible case in full.

Heat, not just water

Roofs in Pune take a serious thermal load, and heat is a waterproofing problem as much as a comfort one. Daily expansion and contraction is what opens the cracks water later exploits, so a reflective finish extends the life of the system underneath it as well as cooling the top floor. On a metal shed the effect on internal temperature is immediate and obvious; on RCC it is slower but the thermal-movement benefit is real. Whether it pays back is a calculation, not a slogan — see our note on cool-roof coatings and energy payback.

Gutters and downpipes: the cheapest fix available

A significant share of “roof leaks” we are called to are drainage failures. A gutter choked with leaves overflows backwards under the eaves; a downpipe disconnected at a joint discharges straight down an external wall and shows up inside as wall dampness two floors below. Neither is fixed by anything applied to the roof.

Before quoting a roof system we check the drainage runs, because if that is the fault, the repair costs a fraction of what a coating would and actually solves the problem.

Diagnosis on a roof is harder than on a terrace

On a pitched or sheeted roof, water entering at a high point can travel a long way along a purlin, a rafter or the underside of a sheet before it drops. The stain inside is a poor guide to the entry point. This is where a survey during or just after rain, combined with thermal imaging and moisture metering, earns its place — the live leak path is visible in a way it simply is not on a dry day. Our free inspection covers this: see leakage detection.

What we quote, and what is guaranteed

Leakproofs by Betterwork quotes roofs against the construction found on site — repair-and-detail where that is the honest answer, a full system where it is not. Rates are supplied-and-applied per sq ft against measured area, with fastener replacement and gutter work itemised separately so you can see what you are paying for.

Completed work is tested before handover and eligible projects carry a written ten-year warranty on the treated area, with exclusions stated on the estimate before you approve it. The standing maintenance item on any roof is the same one: clear the gutters and outlets before the monsoon and again in August.