Your home’s foundation keeps everything standing. When it cracks, settles, or shifts, you need to act fast. This guide explains every major foundation repair method, what each one costs, and when to use it.
What Is Foundation Repair and Why Does It Matter?
Foundation repair fixes structural damage to the concrete, stone, or brick base that supports your home. Cracks, settling, and water damage weaken this base over time. Left alone, foundation problems spread to walls, floors, and roofs.
Most foundation issues come from:
- Soil that expands and contracts with moisture
- Poor drainage around the home
- Tree roots pushing against concrete
- Age and normal wear
- Plumbing leaks underneath the structure
Repairs range from simple crack filling to complete foundation replacement. The method depends on your foundation type, damage severity, and soil conditions.
Common Signs You Need Foundation Repair
Spot these warning signs early:
- Cracks wider than 1/4 inch in walls or floors
- Doors and windows that stick or won’t close
- Gaps between walls and ceiling
- Sloping or uneven floors
- Water pooling near the foundation
- Basement flooding or dampness
- Cracks in exterior brickwork
One or two small cracks don’t always mean disaster. But multiple symptoms together signal a real problem.
Main Foundation Repair Methods
Crack Injection (Epoxy and Polyurethane)
This method fills narrow cracks with liquid material that hardens inside.
How it works: Contractors drill small holes along the crack and inject epoxy or polyurethane under pressure. The material flows through the entire crack and bonds the concrete back together.
Best for:
- Cracks less than 1/2 inch wide
- Non-structural hairline cracks
- Stopping water leaks in basement walls
- Concrete slab foundations
Cost: £300 to £1,200 per crack depending on length and location.
Epoxy creates a rigid repair stronger than the original concrete. Polyurethane foam expands to fill voids and remains flexible. Choose epoxy for structural repairs and polyurethane for active water leaks.
This method works fast. Most crack injections finish in a few hours. The material cures within 24 hours.
Underpinning (Pier and Beam Installation)
Underpinning adds new support beneath your existing foundation. This stops settling and lifts sunken sections back to level.
Steel Piers: Workers drive steel tubes deep into stable soil or bedrock. Hydraulic jacks transfer the home’s weight onto these piers.
Helical Piers: These look like large screws. Machines twist them into the ground until they reach load-bearing soil. They work well in tight spaces where heavy equipment can’t go.
Concrete Piers: Contractors dig holes beneath the foundation and pour concrete columns. This older method still works but takes longer than steel options.
Best for:
- Severe settling (more than 2 inches)
- Foundations sinking into soft soil
- Homes on expansive clay
- Lifting structures back to original height
Cost: £1,200 to £2,500 per pier. Most homes need 8 to 12 piers.
Underpinning provides permanent support. The British Standards Institution sets guidelines for proper installation depths and load capacities. A qualified structural engineer should assess your foundation before underpinning begins.
The process takes one to two weeks for a typical home. Expect some disruption to landscaping around your foundation.
Slabjacking (Mudjacking and Polyurethane Foam Lifting)
Slabjacking raises sunken concrete slabs by pumping material underneath. This levels floors, patios, driveways, and garage slabs.
Traditional Mudjacking: Contractors drill 5cm holes through the concrete and pump a cement-based slurry underneath. The pressure lifts the slab.
Polyurethane Foam Injection: Similar process but uses expanding foam instead of cement slurry. The foam weighs much less and expands to fill voids completely.
Best for:
- Sunken concrete slabs
- Uneven garage floors
- Tilted porch or patio sections
- Trip hazards on walkways
Cost: £700 to £1,800 per slab section.
Polyurethane foam costs more but offers advantages. It weighs 90% less than mud, so it won’t compress soft soil further. The foam also cures in 15 minutes versus 24 hours for cement slurry. You can use the area immediately.
Both methods work well when voids exist under the concrete. If soil has washed away completely, you’ll need more extensive repairs.
Wall Anchors and Braces
These systems stabilise and straighten bowing or leaning foundation walls.
Wall Anchors: Steel plates attach to the inside basement wall. Long rods extend through the soil to anchor plates buried in the yard. Tightening the rods pulls the wall back toward its original position.
Carbon Fibre Straps: Technicians epoxy carbon fibre strips to cracked walls. The straps prevent further bowing but don’t straighten existing damage.
Steel I-Beams: Vertical steel beams bolt to basement walls and floor joists above. They provide rigid support against soil pressure.
Best for:
- Bowing basement walls
- Walls pushed in by expansive soil
- Horizontal cracks from lateral pressure
- Preventing further movement
Cost: £800 to £1,500 per anchor or brace.
Wall anchors work best for active problems where walls continue moving. The system allows gradual straightening over time by tightening the anchors every few months.
Carbon fibre suits minor bowing (less than 5cm) where you want to prevent worsening. I-beams handle moderate damage but take up interior space.
According to HomeAdvisor UK, most structural engineers recommend wall anchors for walls displaced more than 5cm.
Drainage Solutions (French Drains and Sump Pumps)
Water causes most foundation problems. Proper drainage prevents future damage.
French Drains: A trench runs along your foundation with perforated pipe surrounded by gravel. Water flows into the pipe and away from your home. Install them inside basements or outside around the perimeter.
Sump Pumps: A pit in the lowest basement point collects water. An automatic pump removes it before it floods your space.
Grading Improvements: Reshape soil around your foundation so it slopes away. This simple fix prevents water pooling against walls.
Best for:
- Basement water problems
- Soil that stays wet around foundations
- Preventing future damage
- Complementing other repair methods
Cost: £1,500 to £4,000 for interior drainage systems; £800 to £2,500 for exterior French drains.
Drainage repairs work alongside structural fixes. No point lifting your foundation if water keeps washing away the soil.
Internal drainage systems work better in finished basements. External systems cost less but require digging around your entire foundation.
Spot Repair and Patching
Minor damage needs only localised attention.
Concrete Patching: Clean out damaged areas and apply hydraulic cement or concrete patch compound. This fixes small holes, spalled sections, and surface damage.
Sealants and Coatings: Waterproof coatings protect foundation walls from moisture. Apply them after fixing cracks and drainage issues.
Best for:
- Surface damage without structural issues
- Small divots or chips in concrete
- Cosmetic repairs after major work
- Preventing minor problems from growing
Cost: £200 to £600 for most spot repairs.
Don’t rely on patching for structural problems. It’s a surface fix only. Use it to seal up foundations after completing major repairs or to maintain foundations in good condition.
Complete Foundation Replacement
Sometimes damage is too severe to repair. Complete replacement means removing the old foundation and building new.
The process:
- Lift the entire house with jacks
- Support it on temporary beams
- Remove old foundation
- Excavate and prepare new base
- Pour new concrete foundation
- Lower house onto new foundation
Best for:
- Foundations crumbling beyond repair
- Incorrect original foundation depth
- Extensive water damage throughout
- Homes over 100 years old with stone foundations
Cost: £15,000 to £50,000+ depending on home size.
This extreme option makes sense when repair costs approach replacement costs. You get a brand new foundation with modern waterproofing and proper depth.
The process takes several weeks. You’ll need temporary accommodation while work proceeds. But you’ll never worry about foundation problems again.
Choosing the Right Repair Method
| Problem | Best Method | Timeline | Typical Cost |
|---|---|---|---|
| Narrow wall cracks | Crack injection | 1 day | £300-£1,200 |
| Severe settling | Steel/helical piers | 1-2 weeks | £10,000-£25,000 |
| Sunken concrete slab | Slabjacking | 1 day | £700-£1,800 |
| Bowing basement wall | Wall anchors | 2-3 days | £6,000-£15,000 |
| Wet basement | French drain + sump pump | 3-5 days | £2,000-£5,000 |
| Minor surface damage | Patching | 1 day | £200-£600 |
| Severe overall damage | Full replacement | 4-8 weeks | £15,000-£50,000+ |
Start with a professional inspection. A structural engineer identifies the root cause and recommends appropriate methods. Don’t choose repairs based on price alone.
DIY vs Professional Foundation Repair
You can handle:
- Filling hairline cracks with caulk
- Improving drainage and grading
- Applying waterproof coatings
- Minor concrete patching
Leave to professionals:
- Anything involving lifting or supporting the structure
- Repairs requiring hydraulic equipment
- Underpinning and pier installation
- Fixing walls that lean or bow
Foundation work is not the place to save money with DIY attempts. Poor repairs lead to bigger problems. Structural mistakes put your home at risk.
Licensed contractors carry insurance and guarantee their work. They know local soil conditions and building codes. The initial cost hurts less than rebuilding after a collapse.
How to Find a Qualified Foundation Contractor
Look for these qualifications:
- Membership in professional associations
- Proper insurance and bonding
- Structural engineering consultation available
- Detailed written estimates
- Transferable warranty (at least 10 years)
- Local references you can contact
Get at least three quotes. Ask each contractor:
- What method do you recommend and why?
- What’s the warranty coverage?
- How long will repairs take?
- What preparation do I need to do?
- Will you handle building permits?
Avoid contractors who:
- Pressure you to decide immediately
- Only offer one solution
- Can’t explain their process clearly
- Won’t provide references
- Require full payment upfront
Foundation Repair Costs in 2026
Budget ranges for common scenarios:
Minor repairs: £500 to £2,500
- Small crack filling
- Surface patching
- Basic waterproofing
Moderate repairs: £3,000 to £12,000
- Slabjacking one side of home
- Installing 4-6 piers
- Wall bracing system
Major repairs: £12,000 to £35,000
- Full perimeter underpinning
- Complete drainage system
- Multiple wall stabilisation
Extensive repairs: £35,000 to £100,000+
- Foundation replacement
- Combined structural and water solutions
- Historical home restoration
Costs vary by region, foundation type, and access difficulty. London and Southeast prices run 20-30% higher than Northern England.
Some home insurance policies cover foundation damage from specific causes like burst pipes. Most exclude damage from settling, soil movement, or poor maintenance. Check your policy carefully.
Preventing Future Foundation Problems
Stop problems before they start:
Control water:
- Clean gutters twice yearly
- Extend downspouts 2 metres from foundation
- Grade soil away from walls (2% slope minimum)
- Fix plumbing leaks immediately
- Water foundation during droughts to prevent soil shrinkage
Maintain consistent soil moisture:
- Soaker hoses around foundation during dry spells
- Avoid big trees within 6 metres of house
- Don’t let soil dry out completely in summer
Monitor regularly:
- Walk around foundation every season
- Photograph any cracks to track growth
- Check basement after heavy rain
- Measure door gaps that seem to worsen
Upgrade drainage:
- Install French drains before problems appear
- Add a sump pump in flood-prone areas
- Waterproof exterior walls
Prevention costs a fraction of repair expenses. A £1,500 drainage system prevents £20,000 worth of foundation damage.
Understanding Different Foundation Types
Repair methods vary based on your foundation type:
Concrete Slab: Common in modern construction. Sits directly on soil with no basement or crawl space. Vulnerable to soil movement underneath. Repairs usually involve slabjacking or limited underpinning.
Crawl Space: Home sits on short walls with accessible space underneath. Allows easier access for pier installation. Must monitor for moisture and pest problems.
Full Basement: Offers living or storage space but creates large walls vulnerable to lateral pressure. Requires careful waterproofing and drainage.
Pier and Beam: Older method using wooden posts or concrete piers. Individual piers can be replaced without major disruption. Watch for wood rot and settling.
Each type develops specific problems. Slab foundations crack from soil expansion. Basement walls bow from external pressure. Pier and beam systems suffer from individual pier failure.
When Foundation Repairs Are Urgent
Call a contractor immediately if you see:
- New cracks appearing rapidly (within days or weeks)
- Doors suddenly won’t close when they did before
- Large gaps forming between walls and ceiling
- Floors sloping noticeably more than last month
- Water entering basement through new cracks
- Visible soil erosion under foundation edges
These signs indicate active movement. Your foundation is failing right now. Quick action prevents catastrophic damage.
Minor issues can wait for scheduled inspections. But active movement demands immediate attention.
The Foundation Repair Process Timeline
Understanding what happens helps you prepare:
Week 1: Initial inspection and assessment. Engineer evaluates damage and recommends solutions. Get multiple quotes.
Week 2-3: Contract signing and permit applications. Contractors order materials and schedule work crews.
Week 4-5: Actual repair work. Duration depends on method and extent of damage. Simple crack injection takes a day. Full underpinning takes two weeks.
Week 6: Final inspection and warranty paperwork. Engineer confirms repairs meet standards.
Most methods let you stay in your home during repairs. Foundation replacement requires temporary accommodation.
Warranty and Guarantee Information
Quality contractors provide:
- Lifetime warranty on materials
- 10-25 year warranty on workmanship
- Transferable warranty to future buyers
- Free annual inspections for warranty period
- Clear terms about what’s covered
Read warranty documents before signing. Some exclude:
- Damage from new plumbing leaks
- Additional settling in different areas
- Problems from soil changes outside their control
- Cosmetic issues not affecting structure
Keep all paperwork. Document any new problems with photos and dates. Contact the contractor immediately if issues arise.
A strong warranty adds value when selling your home. Buyers want proof of professional repairs with ongoing protection.
Summary
Foundation repairs range from simple crack filling to complete replacement. Choose methods based on damage type, foundation style, and soil conditions. Most homes need professional help for anything beyond minor patching.
Start with proper diagnosis from a structural engineer. Get multiple quotes from licensed contractors. Don’t delay repairs once you spot warning signs.
Prevention through drainage and moisture control saves massive expense later. Monitor your foundation regularly and act fast on changes.
Quality repairs with proper warranties protect your largest investment. Your foundation literally holds up everything else. Give it the attention it deserves.
Frequently Asked Questions
How long do foundation repairs last?
Quality repairs with proper materials last 25 to 50 years or more. Steel pier systems often outlast the home itself. Crack injections with epoxy provide permanent fixes if the underlying cause is addressed. Wall anchors work indefinitely when properly maintained. The key is fixing the root cause, not just symptoms. A repair without proper drainage will fail again within years.
Can I sell my house with foundation problems?
Yes, but expect lower offers and limited buyer interest. Most mortgage lenders won’t approve loans for homes with active foundation issues. Buyers will demand repair credits or significantly reduced prices. You’re better off fixing problems before listing. Proper repairs with transferable warranties actually add value. Disclose all known issues honestly to avoid legal problems later.
Will foundation repair damage my home?
Minor cosmetic damage happens during most repairs. Expect small cracks in plaster or drywall from lifting and shifting. Landscaping around the foundation gets disturbed. But structural damage to the home is rare with professional contractors. They use proper jacking techniques and monitor closely. Plan to repaint and do minor cosmetic fixes after major foundation work. The alternative of not repairing causes far worse damage over time.
How do I know if my foundation crack is serious?
Cracks wider than 1/4 inch need professional evaluation. Horizontal cracks indicate serious pressure problems. Stair-step cracks in brick or block walls signal foundation movement. Any crack that grows noticeably over weeks or months is serious. Cracks with vertical displacement (one side higher than the other) show structural failure. Hairline cracks less than 1/8 inch are normal settling in most homes. When in doubt, get an inspection. A few hundred pounds for an engineer’s report beats thousands in emergency repairs.
Do foundation repairs increase home value?
Completed repairs with warranties typically restore full home value. You rarely recoup 100% of repair costs as added value. But you avoid massive value loss from unrepaired damage. Homes with documented foundation problems sell for 10-20% less than comparable homes. Professional repairs with transferable warranties remove this discount. Think of repairs as protecting existing value rather than adding new value. Buyers want peace of mind that the foundation is sound.