Cobham · Surrey
Extension pulling away repairs in Cobham
For many Cobham homes, the extension was added decades after the house was built, on concrete that never matched the original footings. Where that difference causes movement, a designed movement joint or a deeper foundation is the usual fix.
Guide price from£670per junction inc VAT
- Postcodes
- KT11
- Population
- about 17,000
- Area
- Surrey
- Pricing region
- South East
How do local ground conditions affect extension pulling away repairs in Cobham?
Cobham is in Surrey and takes in postcode districts KT11. About 17,000 people live there. If you are just outside Cobham, we also cover Esher (3 miles), Weybridge (4 miles) and Leatherhead (4 miles).
Shrinkable clay is widespread in Surrey. Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across Surrey: Victorian and Edwardian villas, 1930s semis and detached houses in the commuter towns, and post-war estates.
Methods for extension pulling away repairs
Underpinning the extension
If the extension is still dropping because its footings are too shallow or on poor ground, they are taken deeper by mass concrete, beam-and-base or mini-piles. The engineer designs the scheme, and the junction is repaired once the new foundation is in.
Best for: Active movement from shallow footings, roots or soft ground
Junction crack repair with stainless ties
The open joint is cut out, stainless ties or helical bars are fixed across it into both the old and new masonry, and the joint is repointed or rendered to match. Inside, the corner is replastered. This suits extensions that moved once and have since stopped.
Best for: Settled extensions with a stable gap at the junction
From first photo to finished repair
Find what is moving
An independent chartered structural engineer can inspect, and we can arrange one. A drain survey under the extension, a trial pit at its footing and tell-tale monitoring across the joint are common checks before choosing the repair.
Choose the fix
The engineer decides between ties, a movement joint or underpinning. We confirm a fixed price in writing once the repair is specified, covering the junction, flashings, internal finishes and any foundation work.
Repair the junction
Drains are repaired first if they are leaking. The joint is then tied, formed as a movement joint or rebuilt after underpinning, with roof flashings reset so the junction stays watertight. Building control is handled where needed.
Symptoms that point to extension pulling away repairs
- A vertical crack or gap where the extension meets the house
- Floor level dropping where the extension and house floors meet
- Mastic or render at the joint repeatedly splitting open
Guide prices for extension pulling away repairs in Cobham
Prices in Cobham are worked out on South East rates. They include VAT and are a starting point: access, the extent of the damage and whether an engineer or building control is involved all move the figure.
| Item | Guide price | Per |
|---|---|---|
| Junction crack repair with stainless tiesest. | £670 – £2,250 | per junction |
| Movement joint and making goodest. | £450 – £1,350 | per junction |
| Underpinning the extension where needed | £1,100 – £2,800 | per metre of wall |
Rules for extension pulling away repairs in England
In England, underpinning and other work that alters or strengthens a wall or foundation is building work under the Building Regulations (Part A, structure), so building control approves and inspects it. Like-for-like repairs often are not, and we tell you which applies before a price is agreed. Work to a party wall, or excavation close to a neighbour’s foundations, can also need a notice under the Party Wall etc. Act 1996.
Frequently asked questions
How much should I budget for extension pulling away repairs in Cobham?
Guide prices for extension pulling away repairs in Cobham start from about £670 per junction, including VAT, on South East rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Can you survey a property in Cobham?
Yes, Cobham is covered, along with postcode districts KT11. We also cover nearby Esher and Weybridge.
Why do houses in Surrey crack?
North Surrey sits on London Clay, the south on Weald Clay, with chalk along the North Downs and sands in the west. Large gardens with mature trees on clay make seasonal subsidence a familiar problem. Only an investigation can say why a particular building has moved.
Can a drain under my extension cause it to move?
Yes, a cracked or displaced drain beneath or beside an extension can soften clay or wash away fine soil. A CCTV drain survey usually finds it. Repairing the drain is often the first and most important step before any repair to the walls.
Who is responsible if a recent extension is moving?
If the extension is recent, the original builder, the designer or building control records may be relevant, and you may have rights against the builder. Gather the plans, completion certificate and contract. Insurance often excludes defects in new construction, so check your policy.
Related work in Cobham
- Bay window subsidence repairs
- Concrete repairs
- Subsidence insurance claim repairs
- Brick arch repairs
- Retaining wall repairs
Extension pulling away repairs near Cobham
Send photos of the extension junction at your Cobham home, inside and out, and we will give a free initial assessment and a guide price.