Foundation Crack: What Every UK Homeowner Needs to Know
Finding a crack in your foundation can feel like a heart attack, but it doesn’t have to end in panic. Most cracks are harmless, and with a few quick checks you can tell if the problem is small or serious.
How to Spot and Measure a Crack
First, grab a flashlight and a ruler. Look for cracks that are:
- Below 0.1 mm – usually just a hairline, no worry.
- Between 0.1 mm and 1 mm – keep an eye on them, especially if they’re growing.
- Over 1 mm – start thinking about professional help.
Measure the width at three spots along the crack and note the widest point. Write the numbers down and check them every month. If the crack widens by more than 0.5 mm in a season, it’s a red flag.
Also, look at the direction. Horizontal cracks often mean pressure from soil, while vertical cracks are usually shrinkage and less dangerous. Stair‑step patterns can signal movement in the foundation.
When to Call a Structural Engineer
If you see any of these signs, pick up the phone:
- Crack wider than 1 mm or spreading quickly.
- Doors and windows that stick or won’t close properly.
- Uneven floors or sloping ceilings.
- Water pooling around the base of the house.
- Visible gaps between walls and the floor.
A structural engineer will do a detailed survey, sometimes using laser levels or drones. Their report will tell you if the foundation needs underpinning, piering, or a simple epoxy fill.
Don’t wait for the crack to double in size. Early action can save thousands on repair bills and keep your home safe.
When you’re ready to fix the crack, you have a few options. Epoxy injection works for small, clean cracks and can restore strength. For larger gaps, carbon fibre straps or steel plates add support. If the soil underneath is shifting, a professional may recommend underpinning with concrete piles.
Before you hire anyone, ask for references, proof of insurance, and a clear quote. The cheapest offer isn’t always the best – a cheap fix can cause more damage later.
In the UK, many insurers have strict clauses about foundation issues. Check your policy to see if a repair is covered, and keep all invoices and engineer reports. Good documentation can make a claim smoother if you ever sell the house.
Quick cheat‑sheet: hairline cracks (<0.1 mm) just monitor, medium cracks (0.1‑1 mm) re‑measure regularly, wide cracks (>1 mm) call a professional.
Bottom line: a visible crack isn’t automatically a disaster, but it does need attention. Measure it, watch it, and know the warning signs. When in doubt, call a structural engineer and get a professional opinion. With the right steps, you’ll protect your home’s value and avoid costly surprises.
