Everything you need to know about foundation repair in London, from spotting early signs of subsidence to expert solutions that protect your home’s strength, safety, and value.
Get clear, practical answers to the questions homeowners ask most.
You can spot foundation problems by looking for warning signs such as cracks in walls, uneven or sloping floors, doors and windows that stick, or gaps between walls and ceilings. Outside, you may notice cracks in brickwork or separation around the base of the home. If you see these signs, a structural survey is the best way to confirm foundation issues.
Yes, buying a house that has been underpinned is safe if the work was carried out by qualified contractors and has certification. Underpinning strengthens the foundation, often making the home more secure than before. Always request the engineer’s reports and insurance-backed guarantees before purchase.
In most cases, you can live in a house while it’s being underpinned, but it depends on the scale of the project. Small sections are usually worked on at a time, meaning disruption is limited. However, for major underpinning, it may be safer and more practical to move out temporarily.
The main disadvantages of underpinning are the cost, disruption during construction, and potential impact on property value if future buyers are wary of structural history. However, when completed properly, underpinning provides a long-term solution that prevents further foundation movement.
A structural issue is any problem that affects the stability and safety of a building. This includes foundation settlement, bowing walls, cracked beams, sagging roofs, or uneven floors. Structural issues go beyond cosmetic defects and can compromise the strength of the home if not repaired.
Foundation repair costs vary widely depending on the extent of the damage and the method used. Minor repairs may cost a few thousand pounds, while full underpinning can range from £10,000 to £50,000 or more. A structural survey is the best way to get an accurate estimate.
Your house may need underpinning if you see cracks wider than 3mm in walls, doors or windows that no longer close properly, sloping floors, or gaps appearing around skirting boards and ceilings. These are signs of foundation movement and should be assessed by a structural engineer.
Underpinning is designed to be a permanent solution. When carried out properly by professionals, it can last the lifetime of the building and stop further foundation movement.
Underpinning can affect property value because some buyers are cautious about structural history. However, if the work is certified, guaranteed, and completed to a high standard, the house is usually more stable and secure than before.
A crack is serious if it is wider than 3mm, runs diagonally, or keeps getting longer over time. Serious cracks often appear near windows, doors, or the corners of a property. A structural engineer can confirm if it’s cosmetic or a sign of foundation problems.
Structural cracks are often caused by foundation movement, subsidence, settlement, or changes in soil moisture levels. Other causes include poor construction, heavy loads, or water damage. Identifying the cause is key to choosing the right repair method.
Yes, most structural damage can be fixed permanently with the right repair method. Underpinning, wall tie replacement, or reinforcement can restore stability. Long-term success depends on addressing the root cause, not just the visible damage.
Settlement is a natural process where a new building sinks slightly into the ground and usually stops over time. Subsidence is ongoing downward movement of the ground under a property, often caused by soil shrinkage, tree roots, or water issues, and usually needs repair.
You may have subsidence if you notice diagonal cracks wider than 3mm, doors and windows sticking, or floors that slope. Cracks often appear near weak points like doors and extensions. A professional survey is the only way to confirm subsidence.
Most home insurance policies cover structural repairs if the damage is caused by an insured risk, such as subsidence. However, they may not cover gradual settlement or poor maintenance. Always check your policy and speak with your insurer before starting repairs.
A structural engineer report in the UK typically costs between £350 and £800, depending on property size and complexity. The report includes a detailed assessment of structural issues and recommended repairs.
Yes, a structural survey is recommended before buying a property, especially if it’s older or shows signs of cracking or subsidence. It identifies hidden structural issues and helps you avoid costly repairs later.
Underpinning usually takes 2 to 6 weeks for an average property, depending on the size of the house and the number of sections being worked on. Larger or more complex jobs may take longer.
Yes, you can sell a house with subsidence, but you must disclose it to potential buyers. Providing evidence of completed repairs and engineer certification can help maintain buyer confidence and property value.
In most cases, underpinning does not require planning permission because it is considered maintenance. However, if your property is listed or in a conservation area, you should check with your local council first.
Alternatives to underpinning include helical piles, micro-piling, and slab jacking. These methods can stabilize the foundation without full excavation and are chosen based on soil type and property condition.
Wall crack repairs typically cost between £250 and £1,500, depending on the severity and whether structural work is needed. Cosmetic cracks are cheaper, while structural cracks may require underpinning or reinforcement.
The most effective way to fix rising damp is to install a damp-proof course (DPC) and improve ventilation. Professional assessment is essential to identify the moisture source and prevent long-term damage.
No, not all cracks are structural. Hairline cracks from plaster shrinkage are normal. Structural cracks are wider than 3mm, diagonal, or continue to grow and often require professional assessment.
To prevent structural damage, maintain proper drainage, control tree root growth near foundations, avoid overloading floors, and fix leaks promptly. Regular structural inspections help detect early issues before they become serious.
Choose a company with professional accreditations, proven experience, and positive customer reviews. Ensure they provide written quotes, engineer reports, and guarantees for their work. Transparency and certifications are key to reliability.
Helical piling is a method of strengthening foundations using screw-like steel piles drilled deep into stable soil. It’s used when a property has subsidence or weak soil and offers a quicker, less invasive alternative to traditional underpinning.
Resin injections can be effective for stabilising small areas of foundation movement or voids beneath floors. However, they are usually a partial solution and may not be suitable for severe or ongoing structural problems, where underpinning is recommended.
Subsidence can reduce a property’s value by 5–20%, depending on severity, history of repairs, and soil type. Fully repaired and certified properties may regain most of their value, but disclosure is required when selling.
Getting a mortgage on a property with structural issues is possible, but lenders often require a structural engineer’s report and evidence of completed or planned repairs. Some lenders may refuse high-risk properties until issues are resolved.
If you suspect foundation issues, contact a structural engineer immediately. Avoid DIY fixes, monitor cracks, and keep records of any changes to help assess severity. Early action prevents costly damage.
Engineers assess subsidence using visual inspections, crack monitoring, soil analysis, and sometimes laser leveling or ground-penetrating surveys. They combine data to determine the cause and extent of movement.
Underpinning strengthens an existing foundation by extending it to stable soil, while piling uses deep steel or concrete piles to support the structure from below. Piling is often faster and used on larger or heavily loaded buildings.
Structural repairs can be moderately disruptive. Expect noise, dust, and temporary access restrictions. Most work can continue around the repair, and professionals minimise inconvenience with careful planning.
Not always. Many underpinning or piling projects allow you to stay in your home if safety precautions are followed. However, in major or high-risk cases, temporary relocation may be recommended.
Older houses often face subsidence, timber decay, wall cracks, damp penetration, and roof or floor sagging. These issues arise from age, poor drainage, or shifting soil.
Yes, minor or non-structural cracks can be repaired with mortar injection, stitching, or cosmetic filler. Structural cracks often require underpinning or reinforcement to prevent recurrence.
A full structural survey is recommended every 5–10 years or before buying, selling, or after noticeable changes such as new cracks, leaks, or subsidence signs.
Signs include rising damp marks, peeling paint, mold growth, and soft or crumbling plaster. A structural engineer or damp specialist can determine if moisture is weakening walls or foundations.
Properly completed structural repairs, like underpinning or piling, can last 50 years or more. Regular maintenance and monitoring ensure long-term stability.
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