Waterproofing for Redevelopment Projects in Mumbai
Redevelopment waterproofing splits into two distinct jobs: keeping an ageing building serviceable and safe while approvals and rehousing proceed, and then getting the new structure's below-grade and podium waterproofing right from the first pour.
A society redevelopment committee member, developer or PMC involved in a redevelopment scheme.
What actually makes this difficult
The technical work overlaps with every other kind of building. The constraints are what differ, and they are what a contractor either understands or does not.
- Interim safety
- The existing building must stay safe and habitable, sometimes for years, without over-investing in it.
- Proportionate spend
- Money spent on a building due for demolition has to be justified.
- New-build sequencing
- Pre-applied systems on the new structure have a single, unrepeatable window.
- Long defect exposure
- The new building's below-grade work cannot be re-accessed after backfill.
How we work on these projects
- For the existing building: targeted, proportionate work that keeps it safe and dry without overspending on a structure with a known end date.
- Honest advice on what is genuinely needed versus what can wait for demolition.
- For the new build: full below-grade and podium detailing, executed to programme with witnessed hold points.
- Complete handover documentation for the new structure's defect liability period.
Systems this kind of project usually needs
- Building Restoration
Building restoration is the structural rehabilitation of an ageing or distressed building — diagnosing why the concrete is failing, repairing it properly, and protecting it so it does not fail again. It covers RCC repair to columns, beams and slabs, rebar treatment, carbon-fibre strengthening where sections have lost capacity, facade renewal and full waterproofing.
- Injection Grouting
Injection grouting forces a cementitious or epoxy grout under pressure into cracks, voids and honeycombed concrete to restore continuity and block water paths. Cementitious grouts fill larger voids economically; epoxy grouts bond structurally and are used where the repair must carry load across the crack..
- Terrace Waterproofing
Terrace waterproofing is the application of a continuous water barrier across a roof slab, laid to a fall so rainwater drains rather than ponds. In Mumbai the usual choices are brick bat coba with china mosaic, an APP or SBS torch-on membrane, or a liquid-applied polyurethane or polyurea coating.
- Basement Waterproofing
Basement waterproofing protects a below-grade structure against groundwater under hydrostatic pressure. Because the water pushes inward continuously, the reliable approach is a box-type system — a continuous barrier wrapping raft and retaining walls — applied pre-construction where possible.
- HDPE Membrane Waterproofing
HDPE membrane waterproofing uses a high-density polyethylene sheet, generally pre-applied below rafts and against retaining walls before concrete is poured. The key property is that fresh concrete bonds mechanically to the membrane's coated face, so water cannot track laterally between barrier and structure — the failure mode that defeats most loose-laid below-grade systems..
- Podium Waterproofing
Podium waterproofing protects a landscaped or trafficked deck sitting above occupied space — typically parking, a clubhouse or retail. It is demanding because the barrier must survive planter soil, vehicle loads and heavy detailing around drains and columns, while any failure shows up as a leak into the space below, where it is expensive to trace..
- Box Type Waterproofing
Box type waterproofing wraps a below-grade structure in a fully continuous barrier — under the raft, up every retaining wall, and sealed at the top — so the structure sits inside an unbroken tank. It is the correct answer where groundwater exerts permanent hydrostatic pressure, because there is no joint or edge for water to find..
Redevelopment Projects — questions we get asked
How much should we spend on a building that will be demolished?
Only what safety and habitability require — arresting active leaks, dealing with falling plaster and spalling that could injure someone, and keeping tanks sound. A full terrace system on a building due for demolition in two years is not a good use of the society's money, and we will say so.
What matters most on the new structure?
The below-grade waterproofing, because it can never be re-accessed after backfill. The raft-to-wall junction and the water stops at construction joints decide whether the basement is dry for the building's life.
Can you handle both the old and the new building?
Yes, and there is an advantage in continuity: the same team already knows the site conditions, the water table behaviour and the ground.
We also work with
Talk to us about your redevelopment project project
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