West Sussex · England
Extension pulling away repairs in West Sussex
Across West Sussex, requests for extension pulling away repairs usually begin with a crack someone has noticed getting wider. West Sussex is one of the parts of the UK where clay soils are most likely to move with the seasons. A repair only lasts if the reason for the movement has stopped.
Guide price from£670per junction inc VAT
- Area
- West Sussex
- Pricing region
- South East
- Ground
- Shrinkable clay widespread
- Towns listed
- 11
How do local ground conditions affect extension pulling away repairs in West Sussex?
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.
Ground movement here is more often linked to soils, drains and trees than to mining. Housing stock in West Sussex: Wealden cottages, 1930s semis and bungalows on the coast, and new-town estates in Crawley.
Repair options we may recommend
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
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 to expect when we carry out extension pulling away repairs
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.
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.
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.
Is it time for extension pulling away repairs? Common signs
- Mastic or render at the joint repeatedly splitting open
- A vertical crack or gap where the extension meets the house
- Patio doors or windows in the extension starting to bind
- Floor level dropping where the extension and house floors meet
What should you budget for extension pulling away repairs in West Sussex?
For West Sussex we use South East rates. Treat the table as a budget guide, inc VAT; the price you pay is the one on your written quote.
| 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 |
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.
Towns in West Sussex we cover for extension pulling away repairs
- Crawley
- Worthing
- Bognor Regis
- Littlehampton
- Horsham
- Haywards Heath
- Chichester
- Burgess Hill
- East Grinstead
- Shoreham-by-Sea
- Lancing
Your extension pulling away repairs questions
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. 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 West Sussex?
On South East rates, extension pulling away repairs starts from about £670 per junction, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.
Is it normal for an extension to crack at the join?
A fine crack at the junction is fairly common, especially in the first few years as a new extension settles. It becomes a concern when the gap is widening, tapering, letting in water or matched by sticking doors and sloping floors. Those signs point to continuing movement.
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.