Foundation Repair Cost Estimator
Estimated Repair Cost
Costs based on UK averages for a typical home. Prices may vary depending on soil conditions, location, and additional work needed.
Important Note: This is an estimation tool only. Actual costs may vary significantly based on your specific situation. Always get multiple professional quotes for accurate pricing.
Prevention Cost Comparison
Preventing foundation issues costs £200-£500 annually. This is significantly less than the cost of a full repair, which starts at £2,000 for slabjacking and £4,000 for helical piers.
If your floors slope toward the center of the house, doors stick like they’re stuck in mud, or you see new cracks in your drywall or brickwork, your foundation might be sinking. This isn’t just a cosmetic issue-it’s a structural emergency. Left unchecked, a sinking foundation can lead to warped floors, broken pipes, even wall collapse. The good news? Most sinking foundations can be fixed, but only if you act fast and know exactly what to do.
Why Foundations Sink in the First Place
Foundations don’t sink because they’re weak-they sink because the soil beneath them changes. In the UK, clay soil is everywhere, especially around London. Clay expands when wet and shrinks when dry. One dry summer followed by a wet autumn can cause the ground to shift under your house. That’s why homes built in the 1970s and 80s, with shallow footings, are now showing signs of trouble.
Other common causes:
- Leaking pipes or gutters soaking the soil near the foundation
- Tree roots pulling moisture from the ground
- Poor drainage or improper grading that directs water toward the house
- Soil erosion from heavy rain or flooding
- Original construction on unstable fill soil
It’s not always obvious. You might not notice a problem until a door won’t close or a tile cracks. That’s why checking your foundation twice a year-once in spring, once in autumn-is critical.
How to Tell If Your Foundation Is Actually Sinking
Not every crack means disaster. But here’s how to tell if it’s serious:
- Diagonal cracks in brickwork or concrete that are wider than 3mm and getting bigger
- Sticking doors and windows that jam on one side but open fine on the other
- Sloping floors-roll a marble across the floor. If it rolls toward the center, your foundation is uneven
- Cracks in plaster or drywall that follow door frames or run from corners upward
- Gaps between walls and ceilings, especially near corners
- Exterior tilting-if your chimney or porch looks like it’s leaning away from the house
Take photos every few months. Compare them. If the cracks are growing, or the slope is increasing, you’re not dealing with normal settling-you’re dealing with active sinking.
What to Do First: Emergency Steps
Don’t panic. Don’t start calling contractors right away. Do this first:
- Stop water from hitting the foundation. Check your gutters. Are they clogged? Are downspouts directing water at least 2 metres away from the house? Fix or extend them.
- Check for leaks. Look under sinks, behind washing machines, near boilers. A slow drip under the floor can soften soil for months before you notice.
- Trim tree roots. If you have large trees within 3 metres of the house, their roots are likely stealing moisture. Consult an arborist before cutting.
- Grade the soil. The ground should slope away from your house at 2cm per metre for at least 1.5 metres. If it’s flat or sloping toward the house, add soil and compact it.
These steps won’t fix a sinking foundation-but they’ll stop it from getting worse. Many homeowners think they need a full repair, but sometimes, just controlling water is enough to halt the movement.
Types of Foundation Repair Methods
There are three main ways to fix a sinking foundation. The method you need depends on your house type, soil, and how bad the damage is.
1. Concrete Piering (Most Common for UK Homes)
This is the go-to fix for brick and block foundations. Steel piers are driven deep-often 4 to 8 metres-until they hit stable bedrock or load-bearing soil. Hydraulic jacks lift the house back to level, then the piers are locked in place.
Pros:
- Permanent solution
- Works on clay soil
- Lifts the house back to original level
Cons:
- Expensive-£5,000 to £15,000 depending on size
- Requires drilling through floors or walls to install
2. Helical Piers (Best for Soft or Unstable Soil)
Think of these as giant screws. Steel shafts with helical blades are twisted into the ground until they grip solid soil. They’re less invasive than concrete piers and work well where bedrock is too deep.
Pros:
- Quick installation-often done in one day
- Works in tight spaces
- Can be installed in winter
Cons:
- Not ideal for very heavy homes
- Requires professional torque testing to ensure load capacity
3. Slabjacking or Mudjacking (For Concrete Slab Foundations)
This is rare in UK homes, but common in newer builds with concrete slabs. A mixture of cement and water is pumped under the slab to lift it back up.
Pros:
- Less disruptive-no major excavation
- Faster and cheaper than piering
Cons:
- Temporary fix-soil still shifts
- Can crack again if water issues aren’t fixed
What Not to Do
There are plenty of DIY myths out there. Don’t fall for them:
- Don’t fill cracks with caulk or epoxy. That’s like putting a bandage on a broken leg. It hides the problem, but the foundation keeps sinking.
- Don’t ignore small cracks. A 1mm crack today can become a 10mm crack in six months. Monitor them.
- Don’t wait for a quote from the cheapest contractor. Foundation repair isn’t a commodity. Look for certified specialists with 10+ years of experience and insurance.
- Don’t assume your home insurance will cover it. Most policies exclude gradual settling. Only sudden collapse from a burst pipe might be covered.
How to Choose a Foundation Repair Company
Not all contractors are equal. Here’s what to look for:
- Ask for proof of insurance. Specifically, liability and workers’ comp. If they don’t have it, walk away.
- Check their experience. Ask how many homes they’ve repaired in your area. Local knowledge matters-clay soil in Surrey behaves differently than in Kent.
- Request a written report. A good company will use a laser level to map the slope and show you exactly where the house has settled.
- Ask about warranties. Reputable companies offer 10-25 year transferable warranties. If they don’t, they’re not confident in their work.
- Get at least three quotes. Prices vary widely. The middle option is usually the safest-not the cheapest, not the most expensive.
Look for members of the Foundation Repair Association (FRA) or British Constructional Steelwork Association (BCSA). These groups enforce standards.
What Happens After the Repair?
Once the house is lifted and piers installed, you’ll need to:
- Repair cracked walls and floors
- Re-plaster or re-tile areas that were damaged
- Re-level doors and windows
- Re-seal any gaps around pipes or utilities
Most repairs take 2-5 days. You’ll need to move furniture out of the way, but you can usually stay in the house. The worst part? Waiting for the weather to dry out before they can start. Rain delays are common in the UK.
After the work is done, keep monitoring. Take new photos. Check your doors and windows every few months. If things start sticking again, call them back-most warranties cover follow-up inspections.
Preventing Future Sinking
Fixing the foundation is only half the battle. Preventing the next one is the real win.
- Install a French drain around the perimeter if you’re in a flood-prone area
- Keep gutters clean and extend downspouts
- Plant trees at least 5 metres from the house
- Water your foundation during dry spells-especially in summer. A slow drip from a soaker hose for 2 hours once a week keeps clay soil stable
- Have a professional inspection every 3-5 years, even if nothing seems wrong
Prevention costs £200-£500 a year. A full foundation repair costs £10,000+. The math is simple.
Can a sinking foundation be fixed without lifting the house?
No-not properly. If the foundation has sunk, the only way to restore structural integrity is to lift it back to level. Patching cracks or adding support underneath without lifting will only delay the problem. The house needs to be returned to its original position to prevent ongoing stress on walls, pipes, and framing.
How long does foundation repair last?
When done correctly with steel piers or helical piers, foundation repair lasts for the life of the home. Most reputable companies offer 10-25 year warranties because the system doesn’t degrade. The piers are anchored in stable soil or bedrock and won’t shift again unless there’s a major geological event.
Will my home insurance pay for foundation repair?
Almost never. Most UK home insurance policies exclude damage from gradual settling, soil movement, or poor drainage. Only sudden events-like a burst pipe causing immediate collapse-might be covered. Always check your policy wording. Don’t assume you’re protected.
Can I sell my house if the foundation is sinking?
You can, but you must disclose it. Buyers will require a structural survey. If the repair hasn’t been done, the sale will likely fall through or be heavily discounted. If you’ve already fixed it with certified work and have warranty papers, it can actually increase buyer confidence. Transparency is key.
How much does foundation repair cost in the UK?
Costs vary by method and home size. For a typical semi-detached house, piering ranges from £5,000 to £15,000. Helical piers start at £4,000 for small repairs. Slabjacking is cheaper at £2,000-£6,000 but less durable. Always get multiple quotes and check what’s included-some companies charge extra for debris removal or wall repairs.
Next Steps: What to Do Today
Don’t wait for the problem to get worse. Here’s your action plan:
- Walk around your house. Look for cracks, slopes, sticking doors. Take photos.
- Check your gutters and downspouts. Clear them out and extend them away from the house.
- Measure the slope of your floor with a level. Note any changes from last year.
- Call three certified foundation repair companies for free inspections. Don’t pay for quotes.
- Ask for their warranty terms and insurance proof in writing.
If you catch it early, you might only need to fix the water issue. If it’s progressed, you’ll need professional help-but you’ll know exactly what to look for. The sooner you act, the less it costs. And the safer your home stays.