Cambridge · Cambridgeshire
Extension pulling away repairs in Cambridge
The ground under Cambridge and Cambridgeshire varies street by street, and extensions built on shallower footings feel those differences first. A trial pit and a drain survey usually tell an engineer how the extension’s foundation is coping.
Guide price from£630per junction inc VAT

- Postcodes
- CB2, CB4
- Population
- about 150,000
- Area
- Cambridgeshire
- Pricing region
- East of England
What should you know about the ground under Cambridge?
Cambridge (CB2, CB4) has around 150,000 residents and sits in Cambridgeshire. Nearby, we also cover Royston (12 miles), St Ives (12 miles) and Newmarket (13 miles).
Cambridgeshire 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. Housing stock in Cambridgeshire: Victorian terraces in Cambridge and Peterborough, fen-edge cottages, and extensive post-war and new-build estates.
What to expect when we carry out extension pulling away repairs
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.
Is it time for extension pulling away repairs? Common signs
- Floor level dropping where the extension and house floors meet
- Daylight or draughts showing through the internal corner joint
- Mastic or render at the joint repeatedly splitting open
What should you budget for extension pulling away repairs in Cambridge?
Prices in Cambridge are worked out on East of England 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. | £630 – £2,100 | per junction |
| Movement joint and making goodest. | £420 – £1,250 | per junction |
| Underpinning the extension where needed | £1,050 – £2,600 | per metre of wall |
Repair options we may recommend
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
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
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.
Your extension pulling away repairs questions
How much should I budget for extension pulling away repairs in Cambridge?
Guide prices for extension pulling away repairs in Cambridge start from about £630 per junction, including VAT, on East of England 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 Cambridge?
We do. Cambridge and the surrounding area are covered, including nearby Royston and St Ives. A free initial assessment from your photos is the first step.
Why do houses in Cambridgeshire crack?
Gault Clay underlies much of the Cambridge area and Oxford Clay the west of the county around Peterborough and Huntingdon, while the northern fens are peat and silt that can shrink as they dry. Both clay and peat ground can move with the seasons. 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.
Will my extension need underpinning?
Often not. Many separating extensions are fixed by repairing a drain, tying the junction or forming a movement joint. Underpinning is for extensions that keep dropping because their footings are too shallow or the ground beneath is poor, as shown by monitoring.
Related work in Cambridge
- Floor joist repairs
- Bowing wall repairs
- Resin injection ground stabilisation
- Gable end wall repairs
- Chimney stack repairs
Extension pulling away repairs near Cambridge
Photos of the crack, the internal corner and the roof flashing are a good start; send them about your Cambridge home and we will reply with a view.