What is actually installed
The slab is cut about 30 cm from the wall along the affected length and the concrete is removed. A trench is dug down to the top of the footing. Perforated pipe goes in on a bed of clear stone, sloped to a sump pit. A dimpled membrane is fixed to the wall from about 30 cm up, lapped into the trench, so water that comes through the wall or at the cove joint runs down behind it and into the pipe instead of across the floor. Clear stone covers the pipe, and the slab edge is re-poured flush with the old floor.
Weep holes are drilled into the bottom course of a block wall so water trapped inside the blocks drains too — otherwise the wall keeps a reservoir behind the membrane.
When it is the right repair
- Water shows up at the joint between the floor and the wall — the most common leak in this town.
- A deck, an addition, a driveway or a neighbour's fence sits against the wall and excavation is not realistic.
- Groundwater rises through the floor in wet months, which points to a pump problem more than a wall problem.
- The leak has to be fixed in winter and cannot wait for the ground to thaw.
When it is not
A block wall wet across a whole elevation with white powder on it is saturated from outside. An interior drain will keep the floor dry, but the wall keeps taking water, the mortar keeps weathering and the room keeps smelling damp. That house wants the wall sealed from outside. We say so at the assessment rather than selling the easier job.
What you will have afterwards
- A continuous drain along the treated wall, tied to a sump with a tested discharge.
- The slab edge re-poured, ready for flooring after a day.
- A diagram of what went in and where — useful the day you sell the house.