Merton · Greater London
Extension pulling away repairs in Merton
An extension pulling away from a Merton house is often a drain problem, a shallow footing or a missing tie-in, rather than a failing building. Finding out which applies decides whether the fix is a junction repair or new foundations.
Guide price from£750per junction inc VAT
- Postcodes
- CR4, SM4, SW19, SW20
- Population
- about 220,000
- Area
- Greater London
- Pricing region
- London
Why does the ground in Greater London matter for extension pulling away repairs?
Merton is one of the 32 London boroughs, with around 220,000 residents in districts such as CR4, SM4, SW19, SW20. We also take enquiries from nearby Wandsworth (3 miles), Sutton (3 miles) and Kingston upon Thames (4 miles).
Greater London is one of the parts of the UK where clay soils are most likely to move with the seasons. Ground movement here is more often linked to soils, drains and trees than to mining. Typical buildings in Greater London: Victorian and Edwardian terraces with shallow footings, inter-war semis in the outer boroughs, and converted flats and mansion blocks.
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
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
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
- Extension roof flashing lifting off the original wall
- Patio doors or windows in the extension starting to bind
- Daylight or draughts showing through the internal corner joint
Guide prices for extension pulling away repairs in Merton
These are guide prices for Merton, using London rates and including VAT. Your written quote follows photos or a survey, and is fixed once the repair is specified.
| Item | Guide price | Per |
|---|---|---|
| Junction crack repair with stainless tiesest. | £750 – £2,500 | per junction |
| Movement joint and making goodest. | £500 – £1,500 | per junction |
| Underpinning the extension where needed | £1,250 – £3,100 | 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
What is the price of extension pulling away repairs in Merton?
Guide prices for extension pulling away repairs in Merton start from about £750 per junction, including VAT, on London rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you carry out extension pulling away repairs in Merton?
We do. Merton and the surrounding area are covered, including nearby Wandsworth and Sutton. A free initial assessment from your photos is the first step.
Does the ground around Merton cause cracking?
Most of Greater London sits on London Clay, among the most shrinkage-prone ground in the UK, with river gravels along the Thames. Subsidence claims here are among the most frequent in the country, especially after dry summers and near street and garden trees. Only an investigation can say why a particular building has moved.
What is a movement joint?
A movement joint is a deliberate, flexible break in a wall that lets two parts of a building move slightly without cracking. It is filled with a compressible material and sealed. At an extension junction it can replace a rigid joint that keeps cracking.
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.
More repairs we carry out in Merton
- Chimney stack repairs
- Structural crack repairs
- Lintel replacement
- Crack stitching
- Roof structure repairs
Extension pulling away repairs near Merton
Photos of the crack, the internal corner and the roof flashing are a good start; send them about your Merton home and we will reply with a view.