▽ +09.00Problem · Basements & below ground
Water is getting into the basement
Damp or water on basement walls or floors, especially at corners and joints.
What you see
- Damp patches or wet lines on walls, often at the wall-floor junction
- Water coming through cracks, tie holes or construction joints
- White salts and peeling paint and plaster
- A musty smell and humid air
- Water around lift pits and sumps
Possible causes
Groundwater or perched water
Water in the soil presses on the walls and slab and enters through any weak path.
Missing or damaged external waterproofing
The membrane was not continuous, was damaged during backfilling or never covered the slab.
Construction joints and tie holes
Common water paths when they were not detailed or sealed properly.
Cracks and honeycombing
Shrinkage cracks and poorly compacted concrete let water through.
Leaking services
Water and drainage pipes, irrigation or nearby tanks can feed the soil.
How it is diagnosed
The diagnosis confirms the cause before any repair is chosen.
Record where and when
Is it constant, seasonal, or after irrigation or tank filling?
Map cracks and joints
Mark the wet zones against the joints, tie holes and penetrations.
Test the water
Checking salts and source helps to tell groundwater from a pipe leak.
Measure moisture
Readings across the walls separate active from residual damp.
Review the drawings
The groundwater level, the original waterproofing specification and the joint design.
- Packer
- Crack
- Injected resin
- Surface seal
Possible solutions
The fix follows the diagnosis; these are the common options and their systems.
Injecting leaking cracks and joints
Polyurethane resin stops active water from inside.
Systems
Internal (negative-side) systems
Crystalline or rigid cementitious coats on sound concrete, once the leaks are stopped.
Systems
External waterproofing where excavation is possible
A continuous membrane with protection and drainage layers.
Repairing damaged concrete
Honeycombs and spalls rebuilt before any coating.
Systems
What not to do
- Painting damp walls: the paint peels and the water stays
- Sealing only the surface of a leaking crack: the water moves elsewhere
- Applying coatings over active leaks
- Ignoring the source, such as a leaking pipe or irrigation
General educational content; final values and requirements follow the manufacturer’s TDS and the approved project specification.
Common questions
What comes first when treating a leaking basement from inside?
Stopping the active leaks by injection; negative-side systems then treat the concrete. External waterproofing remains the stronger option for new buildings.
Is it groundwater or a pipe?
Timing, location and a water test usually tell; a constant leak near services points to a pipe.
Why does water appear where the basement floor meets the wall?
Usually through the construction joint between the raft and the wall, where there is no waterstop or it is defective. It is treated by injection, then negative-side systems on the corner and wall.
Technical inspection
Need a diagnosis for your case?
Send photos, a description and the location; our engineers identify the cause and the fix after an inspection.