Worthing · West Sussex
Extension pulling away repairs in Worthing
If the corner joint in your Worthing 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
- BN11, BN12, BN13, BN14
- Population
- about 110,000
- Area
- West Sussex
- Pricing region
- South East
What should you know about the ground under Worthing?
Worthing is in West Sussex and takes in postcode districts BN11, BN12, BN13, BN14. About 110,000 people live there. We also take enquiries from nearby Lancing (2 miles), Shoreham-by-Sea (5 miles) and Littlehampton (7 miles).
Shrinkable clay is widespread in West Sussex. Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across West Sussex: Wealden cottages, 1930s semis and bungalows on the coast, and new-town estates in Crawley.
Guide prices for extension pulling away repairs in Worthing
Prices in Worthing are worked out on South East 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. | £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
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
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
- A vertical crack or gap where the extension meets the house
- Daylight or draughts showing through the internal corner joint
- Patio doors or windows in the extension starting to bind
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 Worthing?
Guide prices for extension pulling away repairs in Worthing 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 Worthing?
Yes, Worthing is covered, along with postcode districts BN11, BN12, BN13, BN14. We also cover nearby Lancing and Shoreham-by-Sea.
Is the ground in West Sussex prone to subsidence?
North West Sussex around Crawley and Horsham sits on Weald Clay, the South Downs are chalk, and the coastal plain has brickearth and gravels. The Weald Clay is prone to shrink-swell movement near trees. Only an investigation can say why a particular building has moved.
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.
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 Worthing
- Subsidence insurance claim repairs
- Subsidence repairs
- Concrete repairs
- Bowing wall repairs
- Lintel replacement
Extension pulling away repairs near Worthing
For a no-obligation written quote to repair an extension pulling away in Worthing, call or send a few photos with a tape measure across the gap.