Horsham · West Sussex
Extension pulling away repairs in Horsham
For many Horsham 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
- RH12
- Population
- about 51,000
- Area
- West Sussex
- Pricing region
- South East
How do local ground conditions affect extension pulling away repairs in Horsham?
Horsham (RH12) has around 51,000 residents and sits in West Sussex. Nearby, we also cover Crawley (7 miles), Horley (11 miles) and Haywards Heath (11 miles).
Shrinkable clay is widespread in West Sussex. 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.
Guide prices for extension pulling away repairs in Horsham
Guide prices below are for homes in Horsham, on South East rates and including VAT. A survey or good photos let us turn them into a fixed written price.
| 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.
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.
Symptoms that point to extension pulling away repairs
- Patio doors or windows in the extension starting to bind
- A vertical crack or gap where the extension meets the house
- Mastic or render at the joint repeatedly splitting open
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 should I budget for extension pulling away repairs in Horsham?
Guide prices for extension pulling away repairs in Horsham 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 Horsham?
We do. Horsham and the surrounding area are covered, including nearby Crawley and Horley. A free initial assessment from your photos is the first step.
Why do houses in West Sussex crack?
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.
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.
Related work in Horsham
Extension pulling away repairs near Horsham
If the junction at your Horsham property keeps reopening, send dated photos and we will suggest whether monitoring, a drain survey or a repair comes next.