Source of seepage
Plumbing shafts
Leaks in the vertical ducts that carry the building's pipes
How water travels
From the source to your wall.
Most apartment buildings run soil, waste, rainwater and supply pipes in vertical shafts next to the bathrooms and kitchens. A cracked pipe, a leaking joint or a branch connection that has come loose wets the shaft walls, and water spreads into the walls of every flat that shares the shaft. Shafts are often closed and hard to reach, so leaks can run for a long time.
When it shows: All year, though rainwater pipes in the shaft leak most during the monsoon.
The pattern it leaves
- Damp on bathroom or kitchen walls backing onto the shaft
- Vertical damp bands that line up floor after floor
- Musty or drain smell near the shaft wall
- Damp that does not follow rain or your own water use
- Stains around the shaft access door, where there is one
How it's confirmed
Meter, thermal, eyes.
- Meter readings on walls next to the shaft, compared with the dry reference
- Thermal scan along the shaft wall, where warm waste lines and cold supply lines can both show without a leak, so every pattern is confirmed with the meter
- Visual check through the shaft opening where it is accessible from the flat or the common area
- Asking neighbours on other floors about similar damp, where possible
Who is usually responsible
It depends on where the water starts.
- Society or association
- Usually responsible for common vertical stacks and the shaft itself, under the society's bye-laws, which vary.
- Owner
- Usually responsible for the branch connections from their own bathroom or kitchen into the stack.
- Builder (within defect period)
- In a new building, a leaking stack or connection brought to the builder's notice within five years from the date of handing over possession falls under Section 14(3) of the RERA Act, 2016. Your state's rules may differ.
Typical repair approach
What a fix usually involves.
Described for understanding, not as a recommendation. Megahedge does not do repairs or recommend contractors.
- 01A plumber accessing the shaft, often from outside or through the access panel, to find the leaking joint
- 02Replacing cracked pipe sections or re-making joints and branch connections
- 03Fixing shaft access so it can be inspected again
- 04Drying and repairing the affected walls in each flat
Questions buyers ask
How do I know if the damp is from the shaft or my own bathroom?
The location and pattern help: damp that lines up with the shaft and appears on other floors points to the shaft. Damp that follows your own fittings points to your bathroom. The report states which is more likely and why.
Who opens the shaft?
Usually the society arranges access. Megahedge does not open shafts or panels.
Can one shaft leak affect several flats?
Yes. Water in a shaft can spread into every flat that backs onto it, which is why the society is usually involved.
Find the damp before you pay for it.
Book a moisture and thermal inspection. Report on WhatsApp within 24 hours.