Bathroom renovation checklist, in build order

The checklist in full

Below is the entire file. Stage three is the only part of a bathroom you cannot revisit without demolishing what came after it.

1 · Survey and demolition

• Existing trap, stack and shaft positions located before anything is broken
• Flat below informed and inspected for existing seepage stains
• Slab sunk or non-sunk established — it changes the whole plumbing plan
• Debris route, chute timing and society deposit arranged
• Existing tiles chipped to the slab, not tiled over

2 · Plumbing first fix

• Hot and cold lines routed with CPVC or composite, pressure-tested for 24 hours
• Drain lines given a 1 in 60 fall minimum to the trap
• Concealed cistern carrier frame fixed and levelled before wall build
• Shower diverter at 42 to 48 in, health faucet at 18 to 24 in AFL
• Geyser point, capacity and its own 16A MCB decided

3 · Waterproofing

• Surface cleaned, cracks cut and filled, corners coved with mortar fillet
• Two coats of membrane, cross-directional, with the second coat a different shade
• Membrane taken 4 ft up the shower wall and 1 ft elsewhere
• Pipe penetrations collared and sealed individually
• 48-hour ponding test done and photographed before tiling
• Waterproofing warranty issued in writing with its start date

4 · Tiling and levels

• Floor fall set to the trap at 1 in 80, checked with water
• Finished bathroom floor kept 10 to 15 mm below the adjoining room
• Tile layout set out so cut tiles fall in the least visible corner
• Anti-skid rating checked for the wet zone, not just the shade
• Skirting, niche and shower ledge tiled with fall towards the floor

5 · Fittings and fixtures

• CP fittings brand and finish confirmed against water pressure available
• WC rough-in distance matched to the fixture before the wall closes
• Vanity height 32 to 34 in with plumbing clear of drawer boxes
• Mirror light and shaver socket positions marked
• Grab bar or a blocked-out fixing point in the shower for later

6 · Ventilation and finishing

• Exhaust fan sized to the room volume and ducted out, not into the ceiling
• Door undercut of 12 mm for make-up air
• Ceiling material chosen for humidity: WPC, PVC or moisture-resistant board
• Silicone rather than grout at every wall-to-floor junction
• Shower glass thickness, hinge type and drip seal confirmed
• 48-hour post-completion leak watch on the ceiling of the flat below

How to use it on site

1. Locate the trap, the stack and the shaft before anything is broken. In older Mumbai buildings these are rarely where the drawing says.
2. Photograph the ponding test with a dated newspaper in frame. It settles every later argument about whose leak it is.
3. Check the floor fall with water, not a spirit level. Pour a litre and watch where it goes.
4. Buy the fixtures before the first fix. WC rough-in distances differ by model, and a wall closed to a generic default will not accept the pan you bought.

The three failures it prevents

• Seepage into the flat below. Stage three sequences the membrane, the coving, the pipe collars and the test in the only order that works.
• Water standing 40 mm from the trap. Stage four sets the fall before tiling rather than discovering it after.
• An exhaust fan ducted into the false ceiling. Stage six sizes the fan to the room volume and requires the duct to reach outside air.

Download the checklist (PDF) →

For 2026 rates see the bathroom renovation cost guide or use the bathroom cost calculator.