Wiltshire · England
Extension pulling away repairs in Wiltshire
Extension pulling away repairs in Wiltshire starts with the ground. Clay soils are found in parts of Wiltshire, and the buildings here are mostly stone cottages, so the repair has to suit both.
Guide price from£620per junction inc VAT

- Area
- Wiltshire
- Pricing region
- South West
- Ground
- Clay in parts
- Towns listed
- 9
Why does the ground in Wiltshire matter for extension pulling away repairs?
Southern Wiltshire is chalk, while the north around Swindon, Chippenham and Trowbridge sits on Oxford and Kimmeridge Clays that are prone to seasonal movement near trees. Bath stone was mined underground around Corsham.
Ground movement here is more often linked to soils, drains and trees than to mining. Housing stock in Wiltshire: Stone cottages, railway terraces in Swindon, and large post-war and new-build estates.
Which repair method suits a home in Wiltshire?
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
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 when we carry out extension pulling away repairs in Wiltshire?
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.
Signs you may need 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
- Extension roof flashing lifting off the original wall
- Daylight or draughts showing through the internal corner joint
How much will extension pulling away repairs cost in Wiltshire?
These are guide prices for Wiltshire, using South West 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. | £620 – £2,050 | per junction |
| Movement joint and making goodest. | £410 – £1,250 | per junction |
| Underpinning the extension where needed | £1,050 – £2,600 | per metre of wall |
Do you need approval 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.
Find extension pulling away repairs in your Wiltshire town
Extension pulling away repairs in Wiltshire: questions and answers
Why do houses in Wiltshire crack?
Southern Wiltshire is chalk, while the north around Swindon, Chippenham and Trowbridge sits on Oxford and Kimmeridge Clays that are prone to seasonal movement near trees. Bath stone was mined underground around Corsham. Ground movement here is more often linked to soils, drains and trees than to mining. Only an investigation on site can say why a particular building has moved.
How much will extension pulling away repairs cost in Wiltshire?
On South West rates, extension pulling away repairs starts from about £620 per junction, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.
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.
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.