The paperwork, in order
- Apply for the NOC with a written scope. What is being removed, what is being installed, that no structural member will be chased and that the wet area is not moving. A clear one-page scope gets approved in days; a vague one generates questions for a fortnight.
- Pay the deposit. ₹25,000 to ₹1,00,000 for a bathroom-only job in most Mumbai societies, refundable against a clean handover and no complaint from below.
- Submit worker ID copies and a fixed crew list. Many buildings now also ask for police verification. Rotating unverified labour mid-project loses site access.
- Sign the leakage undertaking — you will be asked to accept liability for water reaching the flat below for a stated period, commonly six to twelve months. Sign it, then insist on the ponding test that makes it safe to have signed.
- Photograph the downstairs ceiling, dated and countersigned, before day one. If a stain already exists, this is the only evidence that it did.
- Book the lift and agree the debris route. ₹500–₹2,000 a day for the lift, car and lobby protected, and bagged debris removed the same day to a BMC-approved site.
Cast-iron stacks, and the conversation with the neighbours
In buildings from roughly 1960 to 1990 the soil stack is cast iron, running through your bathroom wall and through the bathrooms above and below yours. By now the joints are the weak point, and about one in four that we open is due for replacement.
- It is a shared line. Replacing the section in your flat means cutting into the stack above and below, which needs the agreement of both neighbours and usually the committee.
- The cost is ₹55,000–₹1,10,000 per stack for replacement in SWR or CPVC, including the making good in three flats.
- Do it while the wall is already open. Coming back for it in year three means demolishing your new tiling and repeating the entire waterproofing cycle.
- Offer to coordinate. Where the flats above and below are also thinking about renovating, a joint stack replacement costs each household far less and removes the argument entirely.
- Where the neighbours refuse, replace what is within your slab, sleeve the junctions properly, and record in writing that the remainder was declined. It is not ideal and it is better than nothing.
Twenty-two days, one stack, and the flat below watching
Rates by suburb
| Area | Basic ₹/sq ft | Mid ₹/sq ft | Premium ₹/sq ft | A 35 sq ft bathroom, mid |
|---|---|---|---|---|
| Bandra West, Juhu, Worli | ₹4,200 | ₹6,400 | ₹9,000 | ₹2.24 L |
| Powai, Chembur, Ghatkopar | ₹3,300 | ₹5,000 | ₹7,400 | ₹1.75 L |
| Andheri West, Goregaon, Malad | ₹3,200 | ₹4,900 | ₹7,200 | ₹1.72 L |
| Borivali, Kandivali, Mulund | ₹3,100 | ₹4,600 | ₹6,800 | ₹1.61 L |
| Thane and Navi Mumbai | ₹3,000 | ₹4,300 | ₹6,200 | ₹1.51 L |
Ex-GST. Floor-area basis, including strip-out to slab, services, screed, waterproofing, tiling, sanitaryware, vanity, glass, lighting and extract. Excludes society deposit and stack replacement.
Monsoon timing
A bathroom is an internal room and the work can technically run all year, but three things get harder between mid-June and late September, and together they add about a week.
| Item | Dry season | Monsoon | What we do |
|---|---|---|---|
| Screed cure before membrane | 48 – 72 hours | 72 – 96 hours | Extend the programme; do not apply early |
| Membrane cure between coats | 6 – 8 hours | 12 – 24 hours | Dehumidifier on the room where the programme is tight |
| Debris movement | Routine | Wet, heavy, and societies object to a wet trail | Double-bagged, covered trolley, protected route |
| Grouting and silicone | Normal | Slower cure, higher mould risk on first fill | Epoxy grout in the wet zone regardless; ventilate hard |
| Door and frame fitting | Normal | Timber swells; a tight fit in August binds in January | Fit with a 3 mm working clearance |
Every Mumbai bathroom we hand over is signed off twice: once by the client and once, informally, by the family in the flat below, who we ask to check their ceiling at the pond test and again at handover.
Greenbox project manager
Living with one bathroom in a Mumbai flat
Most flats we work in here have one bathroom and a family that is not moving out for a month. Our standard arrangement is to bring the WC back into temporary service at the end of the services stage on about day seven, remove it again on day thirteen for tiling, and refit permanently on day twenty-two. It adds roughly two working days and it is the difference between a manageable renovation and a hotel bill. A zipped dust screen at the door with a negative-pressure fan venting to the window keeps the rest of the flat usable, and it costs about ₹8,000.
What we find in Mumbai bathrooms specifically
Five discoveries recur here more than they do elsewhere in India, and all five are functions of the building stock and the climate rather than of poor workmanship.
- Layer upon layer of tiling. A 1972 bathroom that has been re-tiled twice without stripping has 60–90 mm of build-up over the slab, no membrane at any level, and a finished floor higher than the passage outside it.
- A floor trap with no accessible route. Original traps bricked into a wall chase during a previous renovation, so a blockage cannot be cleared without breaking tile. We relocate the access, not the trap.
- Salt-corroded fittings in seafront flats. In Juhu, Bandstand and Versova, standard SS 304 concealed cistern frames and mixer bodies corrode within five to seven years. SS 316 and a serviceable access panel are the answer.
- Condensate from an AC drain routed into the bathroom stack. Common, and it means the trap is permanently wet and the stack carries flow when nobody is using the bathroom.
- Chases cut into a beam by a previous contractor. Discovered when the plaster comes off. It needs a structural engineer’s view before anything is closed, and in a society it needs to be reported rather than covered.
The works sequence
The strip-out, discovery, cure and test sequence is the same everywhere and is set out in full on bathroom renovation services. For rate bands by specification level see bathroom renovation cost in Mumbai, and if the bathroom is being replanned rather than replaced, bathroom designers in Mumbai.
Selected work by Greenbox Design Studio. Tap any image to enlarge.
Frequently asked questions
What does a bathroom renovation cost in Mumbai?+
₹3,000–₹6,200 per sq ft of floor area in Thane and Navi Mumbai, ₹3,200–₹7,200 across the western suburbs and ₹4,200–₹9,000 in Bandra West, Juhu and Worli, from basic to premium. A 35 sq ft bathroom at a mid specification therefore runs about ₹1.51 lakh to ₹2.24 lakh, ex-GST and excluding the society deposit.
What does a Mumbai society require for bathroom work?+
A written scope, an NOC, a refundable deposit of ₹25,000–₹1,00,000, worker ID copies and often police verification, a lift booking at ₹500–₹2,000 a day, same-day bagged debris removal to a BMC-approved site, and a signed undertaking accepting liability for any leakage reaching the flat below for a stated period.
Should I replace the cast-iron stack?+
If the building is pre-1990 and the joints show corrosion, yes, and do it while the wall is open. Replacement in SWR or CPVC costs ₹55,000–₹1,10,000 per stack including making good in three flats, and because it is a shared line it needs the agreement of the flats above and below. Coming back for it later means demolishing your new tiling.
How long does a Mumbai bathroom renovation take?+
Twenty to thirty working days under 10am–6pm society hours with no Sunday work. Roughly five of those are screed cure, membrane cure and the 48-hour ponding test, which cannot be compressed. In the monsoon the cure times extend and the programme typically adds about a week.
Can I stay in the flat if it is my only bathroom?+
Yes. We refit the WC temporarily at the end of the services stage around day seven, remove it again on day thirteen for tiling and refit permanently around day twenty-two. That adds about two working days. A zipped dust screen with a negative-pressure fan venting to the window keeps the rest of the flat usable for around ₹8,000.
What if the flat below complains about a leak afterwards?+
This is why we photograph their ceiling before day one, invite them to inspect at the 48-hour ponding test, run a second short pond after all penetrations are made, and document both. With that record, an existing stain cannot be attributed to your work and a genuine new leak is identified quickly rather than argued about for months.