Hillingdon · Greater London
Extension pulling away repairs in Hillingdon
If the corner joint in your Hillingdon 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£750per junction inc VAT
- Postcodes
- HA4, UB3, UB4, UB7, UB8
- Population
- about 300,000
- Area
- Greater London
- Pricing region
- London
What is the ground like in Greater London?
We cover the whole of Hillingdon, including postcode districts HA4, UB3, UB4, UB7, UB8; about 300,000 people live in the borough. Nearby places we cover include Ealing (5 miles), Gerrards Cross (6 miles) and Hounslow (6 miles).
Greater London is one of the parts of the UK where clay soils are most likely to move with the seasons. Ground movement here is more often linked to soils, drains and trees than to mining. Typical buildings in Greater London: Victorian and Edwardian terraces with shallow footings, inter-war semis in the outer boroughs, and converted flats and mansion blocks.
Methods for extension pulling away repairs
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
From first photo to finished repair
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.
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
- Daylight or draughts showing through the internal corner joint
- Floor level dropping where the extension and house floors meet
- Patio doors or windows in the extension starting to bind
Guide prices for extension pulling away repairs in Hillingdon
The ranges below reflect typical London 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. | £750 – £2,500 | per junction |
| Movement joint and making goodest. | £500 – £1,500 | per junction |
| Underpinning the extension where needed | £1,250 – £3,100 | per metre of wall |
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 Hillingdon?
Guide prices for extension pulling away repairs in Hillingdon start from about £750 per junction, including VAT, on London rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you cover Hillingdon?
We do. Hillingdon and the surrounding area are covered, including nearby Ealing and Gerrards Cross. A free initial assessment from your photos is the first step.
Is the ground in Greater London prone to subsidence?
Most of Greater London sits on London Clay, among the most shrinkage-prone ground in the UK, with river gravels along the Thames. Subsidence claims here are among the most frequent in the country, especially after dry summers and near street and garden 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.
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.
Other structural repairs in Hillingdon
Extension pulling away repairs near Hillingdon
Share the loss adjuster’s schedule for your Hillingdon extension claim, and we will price the junction repair and making good to it in writing.