Egham · Surrey
Extension pulling away repairs in Egham
If the corner joint in your Egham extension keeps splitting after you fill it, something is still moving. Measuring the gap over a few months, with dated photos, gives an engineer the evidence to recommend the right repair.
Guide price from£670per junction inc VAT

- Postcodes
- TW20
- Population
- about 30,000
- Area
- Surrey
- Pricing region
- South East
What is the ground like in Surrey?
Postcode districts TW20 cover Egham, a Surrey town of about 30,000 people. If you are just outside Egham, we also cover Staines-upon-Thames (2 miles), Chertsey (4 miles) and Ashford (4 miles).
Shrinkable clay is widespread in Surrey. Ground movement here is more often linked to soils, drains and trees than to mining. Across Surrey, most homes are Victorian and Edwardian villas, 1930s semis and detached houses in the commuter towns, and post-war estates.
Guide prices for extension pulling away repairs in Egham
Guide prices below are for homes in Egham, on South East rates and including VAT. A survey or good photos let us turn them into a fixed written price.
| 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 |
Methods for extension pulling away repairs
Movement joint and making good
Where some seasonal movement is expected to continue, the junction is formed into a proper flexible movement joint with a compressible filler and sealant, so the two parts can move without cracking. Flashings and internal finishes are detailed to suit.
Best for: Minor ongoing movement that does not threaten the structure
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
Show us the junction
Send photos of the crack outside, the internal corner and any flashing above, with a measure for scale. We give a free initial assessment and an initial view on whether the gap is likely old or still opening.
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
- Extension roof flashing lifting off the original wall
- A vertical crack or gap where the extension meets the house
- Mastic or render at the joint repeatedly splitting open
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 will extension pulling away repairs cost in Egham?
Guide prices for extension pulling away repairs in Egham 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.
Do you cover Egham?
Yes. We take enquiries from across Egham, including TW20, and from nearby places such as Staines-upon-Thames and Chertsey. Send photos for a free initial view and we will tell you what happens next.
Is the ground in Surrey prone to subsidence?
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.
Why is my extension pulling away from my house?
Usually because the extension and the house sit on different foundations that react differently to the ground. Shallow extension footings, leaking drains under the extension, nearby roots and weak tie-ins between old and new walls are the common causes.
Can I just fill the gap with mastic?
Mastic can keep water out short term, but it does not stop movement or reconnect the walls. If the gap reopens after filling, something is still moving. Photograph and measure it over a few months first, so an engineer can see the trend.
Other structural repairs in Egham
- Crack stitching
- Floor joist repairs
- Boundary and garden wall repairs
- Roof structure repairs
- Subsidence insurance claim repairs
Extension pulling away repairs near Egham
For a no-obligation written quote to repair an extension pulling away in Egham, call or send a few photos with a tape measure across the gap.