Source of seepage
Rising damp
Ground moisture drawn up into ground-floor walls
How water travels
From the source to your wall.
Brick and block walls draw water up from the ground by capillary action. A damp-proof course at plinth level is meant to stop this. Where it is missing, broken, or bridged by plaster, flooring or soil built up outside, ground moisture rises into the walls of ground-floor flats and independent houses, carrying salts that collect at the height where the water evaporates.
When it shows: All year on ground floors, worst during and after the monsoon.
The pattern it leaves
- A band of damp and salts along the bottom of walls, often up to a metre high
- Tide marks with a wavy upper edge above the skirting
- Damp on internal as well as external walls on the ground floor
- Crumbling plaster and peeling paint low on the wall
- Worse after the monsoon when the ground is saturated
How it's confirmed
Meter, thermal, eyes.
- Meter readings at several heights above the floor; rising damp usually reads highest at the bottom and falls off with height
- Pinless readings alongside pin readings, because salts at the base of the wall can raise pin readings even when it has dried
- Thermal scan along the base of the walls, with each cool band confirmed by the meter
- Checking for bridging: outside ground or paving above the plinth, plaster run down to the floor, or planters against the wall
- Ruling out a leaking pipe or bathroom on the other side, which can look similar
Who is usually responsible
It depends on where the water starts.
- Owner
- Usually responsible in an independent house, and often for the interior of a ground-floor flat.
- Society or association
- May be responsible where the cause lies in the building's plinth, common paving or drainage, under the society's bye-laws, which vary.
- Builder (within defect period)
- In a new building, a missing or defective damp-proof course 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.
- 01Removing bridging: lowering outside ground or paving, cutting plaster back above the floor line, moving planters
- 02Installing a chemical damp-proof course by injection, or other methods chosen by a waterproofing specialist
- 03Removing salt-laden plaster and re-plastering with a mix suited to damp walls once the wall has dried
- 04Improving drainage around the building
Questions buyers ask
Can rising damp affect a first-floor flat?
Not from the ground in a normal RCC building. Damp low on walls above the ground floor usually comes from a pipe, bathroom or balcony.
Why do my readings stay high after the wall has dried?
Salts left by years of rising damp conduct electricity and raise pin meter readings. That is why readings are compared with pinless readings and a dry reference wall.
Will waterproof paint on the inside stop it?
It can push the damp higher up the wall instead. The water needs to be stopped at the base.
Find the damp before you pay for it.
Book a moisture and thermal inspection. Report on WhatsApp within 24 hours.