Crack Fix: Simple Steps to Repair Foundation Cracks
If you’ve noticed a line creeping across your walls or floor, you’re probably wondering if it’s a harmless hairline or a sign of serious trouble. The good news is most cracks can be judged, measured and dealt with without pulling the whole house apart. Below you’ll find a no‑nonsense plan to figure out what you’re looking at, decide if it’s safe to fix yourself, and choose the right material for a lasting repair.
Spotting and Measuring Cracks
First, get a good look. Use a flashlight and a ruler or a crack‑width gauge. If the crack is under 1 mm, it’s usually just shrinkage – nothing to lose sleep over. Anything wider than 3 mm (about the thickness of a pencil) deserves a closer look. Check the direction: vertical cracks often point to settlement, while horizontal ones can signal pressure from soil or water.
Take notes of where the crack appears – corners, load‑bearing walls, near doors – and whether it’s getting longer over a few weeks. A quick way to test growth is to tape a piece of paper across the crack and mark the ends. Re‑measure after a few days; any movement means the foundation is still shifting.
When in doubt, call a structural engineer. They’ll inspect for signs like doors that stick, uneven floors, or moisture stains. A professional opinion saves you from costly missteps later on.
Choosing the Right Repair Method
For minor cracks (up to 2 mm), a simple epoxy filler works well. Clean the crack, apply the epoxy with a putty knife, and smooth it flat. The bond creates a flexible seal that moves with the house, preventing water infiltration.
Wider cracks need something stronger. Hydraulic cement is the go‑to for gaps over 3 mm. It expands as it sets, pushing back against the surrounding concrete. Mix it to a thick paste, press it firmly into the crack, and smooth the surface. Let it cure for 24–48 hours before painting.
If the crack is a symptom of a deeper issue – like soil movement or poor drainage – you’ll need a structural fix. This could involve underpinning with steel piers, installing a French drain, or adding a concrete skirt around the foundation. These solutions are best left to a qualified contractor who knows UK building regs and can obtain any necessary permits.
Don’t forget about the surrounding environment. Poor drainage often makes cracks worse. Check that gutters direct water away from the house, and consider a ground‑level drainage system if the soil stays soggy. Simple fixes like a splash‑back or a slight slope away from the foundation can stop new cracks from forming.
Insurance can be a wildcard. Some policies cover foundation damage only if it’s caused by an external event (like a burst pipe). Read your policy carefully and keep records of any repair work – it’ll help if you ever need to make a claim.
Finally, keep an eye on the repaired area. A small amount of new cracking can be normal settlement, but if you see the same crack reopening or spreading, call a professional again. Early intervention prevents a small nuisance turning into a costly rebuild.
Bottom line: measure, assess, and choose a fix that matches the crack’s size and cause. With the right tools and a bit of know‑how, most crack problems can be solved quickly and affordably, keeping your UK home safe and sound.
