DIY guideBasement and foundation
Seal the foundation cracks and failing parging
Fill thin, dry cracks with concrete crack filler and patch small spots of loose parging. A crack that's wide, growing or leaking is a foundation pro's.
- 1 hr to 3 hr
- 7 steps
- Every step animated
7 steps
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Fill only thin, dry cracks that haven't grown past their marks. Anything wider, growing or leaking goes to the last step.
Brush out loose bits and dust with a wire brush, then vacuum it. Let it dry.
Wear safety glasses and gloves.Squeeze concrete crack filler into the crack from the bottom up, pushing it in. Smooth it flush with a putty knife.
Outside, tap the parging, the thin coat on the foundation above the ground, with a hammer's handle. Chip off what sounds hollow or crumbles.
Glasses on: chips fly.Brush the dust off and mist the bare spot with water so the patch sticks.
Mix a little parging mix and press it on with a trowel, level with the coat round it. Mist it for a day or two while it cures.
The crack is wider than a coin's edge, keeps growing, runs in steps or sideways, leaks water, or the wall bows: ask Handyman for a foundation pro. That's structural work.
What you need
- Concrete crack filler
- A wire brush and a vacuum
- A putty knife and a trowel
- Parging mix and a bucket
- Safety glasses and gloves
Call a pro if
- A crack is wide, growing or leaking
- A crack runs in steps or sideways
- A wall bows or leans
Handyman says: Wide or leaking? I'll find a pro.
Free for every home. Handyman asks a few questions, then books a pro it trusts.
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