Overhead Water Tank (OHWT) Waterproofing in Dadar
Overhead Water Tank (OHWT) Waterproofing in Dadar means treating the specific way buildings fail in G/North Ward: ageing rcc with carbonation-driven corrosion and terrace systems several cycles past renewal. With around 2,200 mm of annual rainfall and 1950s-70s co-operative housing societies dominating here, the specification follows the exposure rather than a standard template. We are about 40 minutes away.
Why buildings in Dadar need this
Water-retaining structures in Dadar are loaded continuously from inside, which is a more demanding duty than any roof. In 1950s-70s co-operative housing societies, tanks are often the original construction with the original lining, and the wall-to-base junction is where they crack first.
The failure patterns we see repeatedly in Dadar are ageing rcc with carbonation-driven corrosion, terrace systems several cycles past renewal, internal plumbing shaft leakage in old societies. Any specification for this locality has to answer those specifically, not generically.
For overhead water tank (ohwt) waterproofing specifically, the defects that cause callbacks are non-potable coating used on a drinking-water tank; wall-to-base junction not filleted, the most common tank crack location; tank returned to service before the lining fully cured. In Dadar's conditions those are not cosmetic shortcuts — chloride reaches the reinforcement through exactly those gaps.
The stock itself is not uniform here. Dadar runs to 1950s-70s co-operative housing societies, Parsi and Hindu colony low-rise, dense commercial mixed-use, spanning roughly 40-75 years. A specification that suits one of those does not automatically suit the next, which is why the survey looks at the actual building rather than the postcode.
One of Mumbai's densest concentrations of old co-operative housing societies. Decision-making runs through managing committees and AGM approval, so scope and cost transparency matter more here than anywhere — a point this page addresses directly. We work throughout the area, including around Shivaji Park, Dadar TT Circle, Dadar Chowpatty.
Overhead Water Tank (OHWT) Waterproofing, specified for Dadar
Continuous immersion and, for potable storage, certification are the two constraints. The lining must be rated for permanent immersion and, where the tank holds drinking water, carry current potable-water certification. The wall-to-base junction is filleted and treated as the critical detail, because that is where tanks in Dadar crack.
Overhead water tank waterproofing lines the internal faces of an elevated potable-water tank with a non-toxic, water-resistant system, and treats the external faces and base where leakage tracks into the structure below. Because the water is for drinking, the internal lining must be a food-grade, potable-water-safe product — not a general-purpose coating.
When this is the right choice here
- Damp or staining on the walls and slab beneath an overhead tank
- Tank due for periodic cleaning and relining
- Visible cracking or seepage at tank wall-to-base junction
When it is not
- A non-potable-rated coating is being considered for a drinking-water tank — this is a health issue, not a preference
- The leak is from the outlet plumbing rather than the tank shell
Full overhead water tank (ohwt) waterproofing specification, method and materials →
Sixty seconds, before you call anyone
- Mark the water level and check it again after 24 hours with the inlet closed. A measurable drop that is not explained by use tells you the structure is losing water, not the fittings.
- Look specifically for evidence of non-potable coating used on a drinking-water tank — it is the most common cause of failure in this system.
- Then check for wall-to-base junction not filleted, the most common tank crack location, which is the next most frequent.
- Separately, look for ageing rcc with carbonation-driven corrosion, which is the pattern this part of Dadar produces regardless of which system was used.
- Photograph it while it is wet, and note whether it worsens with rain or with usage. Rain-linked points to the building envelope; usage-linked points to plumbing. That single distinction settles most arguments about who is responsible.
- Do not chip into a saturated ceiling or paint over a damp patch. The first risks bringing plaster down on someone; the second destroys the evidence needed to trace the path.
How overhead water tank (ohwt) waterproofing is carried out in Dadar
The sequence below is the same wherever the work is done. What changes in Dadar is where the risk concentrates: given that the recurring local problems are ageing rcc with carbonation-driven corrosion and terrace systems several cycles past renewal, the stages worth watching most closely here are treat cracks and form fillets.
The tank is drained, scrubbed and disinfected. Loose material, old lining and scale are removed mechanically. Cracks are cut and filled, and a cement fillet is formed at every wall-to-base and wall-to-wall junction. The substrate is brought to a saturated surface-dry condition before a cementitious lining is applied, because a dry, absorbent substrate pulls water out of the mix and prevents it curing properly.
- 01
Drain, clean and inspect
The tank is emptied and cleaned, then inspected dry so the actual crack pattern and any structural distress are visible rather than guessed at.
- 02
Treat cracks and form fillets
Cracks are cut and filled. A fillet is formed at every internal angle, particularly the wall-to-base junction, which is where overhead tanks crack most often because of the restraint at the base.
- 03
Seal external and structural defects
Where water has been tracking into the supporting structure, the external faces and the slab beneath are treated as part of the same scope. Lining the inside alone leaves the structure below still wet.
- 04
Apply a potable-certified lining
A lining certified as safe for contact with drinking water is applied in multiple coats to 1.5–2.0 mm. This is a health requirement, not a preference — a general-purpose waterproofing coating inside a drinking-water tank is not acceptable regardless of how well it performs technically.
- 05
Cure fully
The lining is cured for the full period stated by the manufacturer before the tank sees water. Filling early is a common shortcut in occupied buildings and it compromises both the bond and the potable safety of the lining.
- 06
Fill test
The tank is filled and the level monitored, with the structure below and around it inspected for any sign of continued seepage.
What we check on site
- Potable-water certification documented for the product used
- Fill test held before handover
- Cure period and flushing logged
Curing
Cure strictly to the manufacturer's stated period — commonly 5–7 days for cementitious potable linings — followed by flushing. This period is not compressible: an under-cured potable lining is both a performance and a water-safety problem.
Materials
- Lining
- Potable-water-certified cementitious or epoxy system. The certificate is supplied to the client as part of handover.
- Crack repair
- Non-shrink polymer-modified mortar, applied into cut grooves.
- Fillets
- Cementitious fillet at all internal angles to remove sharp corners the lining would otherwise thin over.
Our nearest documented project, and how far we are
~40 min
Our office is in Jogeshwari West, about 13 km from Dadar — normally around 40 minutes outside peak traffic.
Travel time is a typical off-peak estimate for Dadar, not a guaranteed response time. Mumbai traffic being what it is, we confirm an arrival window when you call.
What overhead water tank (ohwt) waterproofing costs in Dadar
Rate per square foot: To be confirmed
We have deliberately not published a rate here. Cost on a Dadar building depends on the area, the condition of the existing structure, access and scaffolding, and how much preparation or structural repair is needed before the system can go on — and those vary far more between two buildings on the same street than they do between localities. The site inspection is free and produces an itemised scope you can compare line by line against any other quotation.
Overhead Water Tank (OHWT) Waterproofing in Dadar — questions we get asked
How quickly can you reach Dadar?
Our office is in Jogeshwari West, about 13 km from Dadar, and we normally allow around 40 minutes in off-peak traffic. We also work regularly in Wadala, Prabhadevi, Parel, so a crew is often already in this part of the city.
Why do buildings in Dadar leak more than elsewhere?
Dadar records roughly 2,200 mm of rain a year, measured at the IMD Colaba observatory, island city. Combined with 1950s-70s co-operative housing societies and Parsi and Hindu colony low-rise in the 40-75 years range, the recurring problems here are ageing rcc with carbonation-driven corrosion and terrace systems several cycles past renewal. It is less that Dadar leaks more, and more that it leaks in a particular and fairly predictable way.
Which BMC ward is Dadar in, and does that matter?
Dadar falls under G/North Ward (G/North), covering pincodes 400014, 400028. It matters practically rather than technically: ward boundaries govern which office handles permissions, notices and any municipal correspondence a society may need during major repair work.
Does being close to the sea change what Dadar needs?
Substantially. Chloride from coastal air penetrates render and cover concrete and drives reinforcement corrosion far faster than inland. Two things follow: repair specifications must remove chloride-contaminated concrete rather than patch over it, and protective coatings should resist water ingress while still allowing the wall to dry outward. Sealing a salt-laden wall with an impermeable coating traps the problem inside.
What does overhead water tank (ohwt) waterproofing usually involve in Dadar?
Continuous immersion and, for potable storage, certification are the two constraints. The lining must be rated for permanent immersion and, where the tank holds drinking water, carry current potable-water certification. The wall-to-base junction is filleted and treated as the critical detail, because that is where tanks in Dadar crack. The scope is confirmed after a site inspection, because the condition of the existing structure changes both the method and the cost more than the locality does.
We also work across South Mumbai
- Overhead Water Tank (OHWT) Waterproofing in Wadala
1.5 km from Dadar · F/North Ward
- Overhead Water Tank (OHWT) Waterproofing in Prabhadevi
1.9 km from Dadar · G/South Ward
- Overhead Water Tank (OHWT) Waterproofing in Parel
2.1 km from Dadar · F/South Ward
- Overhead Water Tank (OHWT) Waterproofing in Sewri
2.8 km from Dadar · F/South Ward
- Overhead Water Tank (OHWT) Waterproofing in Lower Parel
2.9 km from Dadar · G/South Ward
- Overhead Water Tank (OHWT) Waterproofing in Sion
3.2 km from Dadar · F/North Ward
Other work we do in Dadar
- Swimming Pool Waterproofing in Dadar
Swimming pool waterproofing lines the pool shell so treated water cannot escape into the structure and so chemically treated water cannot attack the concrete.
- Terrace Waterproofing in Dadar
Terrace waterproofing is the application of a continuous water barrier across a roof slab, laid to a fall so rainwater drains rather than ponds.
- Basement Waterproofing in Dadar
Basement waterproofing protects a below-grade structure against groundwater under hydrostatic pressure.
- Bathroom Waterproofing in Dadar
Bathroom waterproofing seals the sunk slab and wet-area walls so water from daily use cannot reach the flat below.
Book a free inspection in Dadar
An engineer visits, traces the actual source, and gives you a written scope. Our office is in Jogeshwari West, about 13 km from Dadar — normally around 40 minutes outside peak traffic.
Mon–Fri 08:00–18:00 · Sat 09:00–16:00 · Jogeshwari West