Basement leak repair
A leak is water coming in at one place you can put a finger on. That is a smaller job than draining a whole basement, provided the spot really is the only way in.
You will be put through to an independent local waterproofing company. Calls may be recorded.
Pin it down first
After the next storm, outline the wet patch on the wall in pencil and write the date beside it. Note how long after the rain began it showed. Water that arrives within minutes is coming from the surface: a gutter, a window well, a walk tilted toward the house. Water that arrives the next day is groundwater.
A wet patch that appears whether or not it rains is not a waterproofing matter. Look for a pipe, a water heater or a washing machine hose above it.
Where basements leak, and the usual repair
A crack in a poured concrete wall
Small ports are glued along the crack and resin is injected until it fills the full thickness of the wall. Polyurethane resin stays flexible and suits a crack that only leaks. Epoxy sets hard and is chosen where the crack also needs strength.
Mortar joints in a block wall
Block is hollow, so water travels inside the wall and comes out far from where it got in. Injection seldom holds. The answer is usually drainage at the foot of the wall or work on the outside.
The hole around a pipe
Where a sewer, water or gas line passes through the foundation, the gap around it is packed with hydraulic cement or injected foam. If the pipe itself is dripping, that part belongs to a plumber.
A basement window
A window well that fills needs a drain at its base, clean stone and a cover. A rotted frame is replaced. Soil that has crept above the sill is cut back.
The outside cellar door
Water gets in where the steel door frame meets the masonry, or runs down the steps. The joint is resealed and a small drain is set at the bottom of the stairwell.
A stone foundation
Rubble walls leak along many joints at once. Repointing the mortar helps. Thick coatings on the inside trap moisture and peel, so drainage is normally part of the plan.
What the repair involves
Crack injection is done from indoors and involves no digging. The wall has to be bare along the crack, so paint is ground off and any panelling in front of it comes down. Resin can ooze from the crack face while it cures; the ports are snapped off afterwards and the surface scraped flat.
Window well and cellar door repairs are outdoor jobs, with some hand digging in a small area.
Things to settle with the company
Leak repair questions
Can I plug a crack myself with hydraulic cement?
You can stop a trickle for a while. Surface plugs sit in the first inch of the crack; water still fills the rest of it and works round the patch. Injection fills the crack through the wall.
Is a hairline crack a worry?
Thin vertical cracks are common in poured walls as concrete cures. One that is dry, straight and has not changed is something to watch, not to fix. Photograph it with a coin for scale once a year.
The leak only shows in the heaviest storms. Is it worth fixing?
That pattern usually means surface water is overwhelming a gutter or a window well. Start outdoors: it may be a drainage fix and not a wall repair at all.