Swanley · Kent
Extension pulling away repairs in Swanley
For many Swanley 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
- BR8
- Population
- about 22,000
- Area
- Kent
- Pricing region
- South East
What should you know about the ground under Swanley?
Swanley (BR8) has around 22,000 residents and sits in Kent. Nearby places we cover include Dartford (4 miles), Bexley (4 miles) and Bromley (5 miles).
Much of Kent sits on clay that shrinks in dry summers and swells in wet winters. Parts of Kent lie on a former coalfield, so a coal mining search is worth checking if movement has no obvious cause. Housing stock in Kent: Victorian terraces in the Medway towns, weatherboarded and Wealden houses, 1930s semis and seaside bungalows.
What to look for before calling about extension pulling away repairs
- Daylight or draughts showing through the internal corner joint
- Extension roof flashing lifting off the original wall
- Mastic or render at the joint repeatedly splitting open
Extension pulling away repairs prices in Swanley
The ranges below reflect typical South East costs for extension pulling away repairs, including VAT. Scaffold, access and making good can push a job to the top of the range.
| 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 |
How we usually approach extension pulling away repairs
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
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
What happens during extension pulling away repairs, step by step?
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.
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.
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 Swanley
How much should I budget for extension pulling away repairs in Swanley?
Guide prices for extension pulling away repairs in Swanley 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 Swanley?
Yes. We take enquiries from across Swanley, including BR8, and from nearby places such as Dartford and Bexley. Send photos for a free initial view and we will tell you what happens next.
Why do houses in Kent crack?
North Kent sits on London Clay, central Kent on Gault and Weald Clays and the Downs on chalk, so shrinkable clay is widespread. East Kent around Deal and Dover had a small deep coalfield, worked until the late 1980s. Only an investigation can say why a particular building has moved.
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.
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.
Related work in Swanley
Extension pulling away repairs near Swanley
Share the loss adjuster’s schedule for your Swanley extension claim, and we will price the junction repair and making good to it in writing.