Truro · Cornwall
Extension pulling away repairs in Truro
For many Truro 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£620per junction inc VAT

- Postcodes
- TR1
- Population
- about 23,000
- Area
- Cornwall
- Pricing region
- South West
What is the ground like in Cornwall?
Truro, Cornwall: about 23,000 residents across postcode districts TR1. Nearby places we cover include Falmouth (8 miles), Redruth (8 miles) and Newquay (10 miles).
Shrinkable clay is less common in Cornwall than in south-east England. Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Housing stock in Cornwall: Granite and slate-stone cottages, cob buildings, Victorian terraces and post-war estates.
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.
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.
Symptoms that point to extension pulling away repairs
- Patio doors or windows in the extension starting to bind
- Daylight or draughts showing through the internal corner joint
- Floor level dropping where the extension and house floors meet
Guide prices for extension pulling away repairs in Truro
For Truro we use South West 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. | £620 – £2,050 | per junction |
| Movement joint and making goodest. | £410 – £1,250 | per junction |
| Underpinning the extension where needed | £1,050 – £2,600 | 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
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 Truro?
Guide prices for extension pulling away repairs in Truro start from about £620 per junction, including VAT, on South West 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 Truro?
Yes. We take enquiries from across Truro, including TR1, and from nearby places such as Falmouth and Redruth. Send photos for a free initial view and we will tell you what happens next.
Why do houses in Cornwall crack?
Cornwall is mostly granite and slate with little shrinkable clay, so clay subsidence is less common than in the south-east. Historic tin and copper mining has left shafts and workings in places such as Camborne and Redruth, and mining searches are routine there. Only an investigation can say why a particular building has moved.
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.
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.
Related work in Truro
- Structural crack repairs
- Bowing wall repairs
- Roof structure repairs
- Boundary and garden wall repairs
- Gable end wall repairs
Extension pulling away repairs near Truro
Photos of the crack, the internal corner and the roof flashing are a good start; send them about your Truro home and we will reply with a view.