Westminster · Greater London
Extension pulling away repairs in Westminster
If the corner joint in your Westminster 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£750per junction inc VAT
- Postcodes
- EC1N, EC4, EC4A, EC4M, EC4N
- Population
- about 200,000
- Area
- Greater London
- Pricing region
- London
Why does the ground in Greater London matter for extension pulling away repairs?
We cover the whole of Westminster, including postcode districts EC1N, EC4, EC4A, EC4M, EC4N; about 200,000 people live in the borough. If you are just outside Westminster, we also cover Kensington and Chelsea (2 miles), Camden (3 miles) and Islington (3 miles).
Much of Greater London sits on clay that shrinks in dry summers and swells in wet winters. Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across Greater London: Victorian and Edwardian terraces with shallow footings, inter-war semis in the outer boroughs, and converted flats and mansion blocks.
Extension pulling away repairs prices in Westminster
Prices in Westminster are worked out on London 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. | £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 |
How we usually approach 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
What happens during extension pulling away repairs, step by step?
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.
Finish and hand over
Internal corners are replastered, skirtings and coving refixed, and doors or windows in the extension eased where the movement affected them. Records of the repair and any approvals are passed to you.
What to look for before calling about extension pulling away repairs
- Mastic or render at the joint repeatedly splitting open
- Patio doors or windows in the extension starting to bind
- A vertical crack or gap where the extension meets the house
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.
Questions about extension pulling away repairs in Westminster
How much will extension pulling away repairs cost in Westminster?
Guide prices for extension pulling away repairs in Westminster 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 cover Westminster?
We do. Westminster and the surrounding area are covered, including nearby Kensington and Chelsea and Camden. A free initial assessment from your photos is the first step.
Is the ground in Greater London prone to subsidence?
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.
Other structural repairs in Westminster
- Brick arch repairs
- Retaining wall repairs
- Roof structure repairs
- Chimney stack repairs
- Resin injection ground stabilisation
Extension pulling away repairs near Westminster
Photos of the crack, the internal corner and the roof flashing are a good start; send them about your Westminster home and we will reply with a view.