Finding the one place it gets in
Basement leak repair
A leak is water entering at a point you can put a finger on: a crack, the gap around a pipe, the bottom corner of a window. If that describes your basement, the repair may be small. The skill is in being sure of the source before anything is sealed.
Call (205) 555-0115Rule out the plumbing first
Water on a basement floor in dry weather is rarely coming through the wall. Check the obvious: the water heater's base and relief pipe, the washing machine hoses, the air conditioner's condensate line and any pipe running across the ceiling above the wet patch.
A simple test for a hidden supply leak: turn off every faucet and appliance, read the water meter, and read it again an hour later. If the dial has moved, water is escaping somewhere, and a plumber is the person to call. Waterproofing will not fix a pipe.
Where walls usually leak
- Vertical cracks in poured concrete. Common and usually harmless to the structure. They leak after rain and leave a rust-colored or white trail.
- Around pipes and cables. The water main, sewer line, gas pipe and electrical conduit each pass through a hole that was packed at the time of building. The packing dries out.
- Form tie holes. Small round spots in a regular pattern on poured walls, left from construction. One or two may weep.
- Window wells. A well full of leaves holds water against the window frame until it spills over the sill.
- Mortar joints in block. Water follows the joints and shows as a damp, stepped line.
Mark the spot with pencil and the date when you see it wet. That mark is the single most useful thing you can show a company.
How each is repaired
A crack in poured concrete is commonly injected. Small ports are fixed along it, the surface is sealed, and resin is pumped in until it fills the crack through the full thickness of the wall. Flexible polyurethane is the usual choice where the aim is to stop water. Ask which resin is proposed and why.
Pipe gaps are cleaned out and refilled with a sealant that stays flexible, because pipes move slightly with temperature. Tie holes are plugged individually. A window well gets its drain cleared or a new one dug, clean stone in the bottom, and sometimes a cover.
Block walls are harder to spot-repair, because water travels sideways inside the hollow cores and may come out somewhere other than where it went in. A company may suggest a short length of interior drain below the wet area instead.
When a single repair will not hold
Sealing one crack sends the water to the next weak point if the soil outside stays saturated. If you have sealed a leak and a new one opened a few feet away, or the damp is along the base of the wall and not at one spot, the problem is general. The wet basement page helps sort that out, and basement waterproofing describes the drain systems used for it.
A crack is also sometimes more than a leak. One that is wider at one end, has shifted so the two faces no longer line up, or runs horizontally along a wall that bulges inward should be seen by a structural engineer or a foundation specialist. Mention it when you call so nobody simply fills it.
What to ask about a leak repair
- What makes you sure this is the source?
- Is the repair made from inside, outside or both?
- Which material is used, and does it stay flexible?
- If the same crack leaks again, what does the written warranty say?
- Is there anything outside, such as a downspout or a low spot, feeding this leak?
Basement leak questions
Can I seal a crack with hydraulic cement?
It stops a trickle for a while. It is rigid and bonds only at the surface, so the crack tends to open beside it. It is a reasonable stopgap until a proper repair.
The leak only happens in the heaviest storms. Is it worth fixing?
That is your decision. Note what is stored near it and whether the wall is finished. Water inside a finished wall does damage you do not see until later.
Do cracks mean my foundation is failing?
Thin vertical cracks in poured walls are mostly from the concrete shrinking as it cured. Width, direction and movement are what matter, and an engineer is the right person to judge those.