St Austell · Cornwall
Extension pulling away repairs in St Austell
Rear and side extensions are common across St Austell, and so is the crack where new meets old. Usually it reflects the two parts sitting on different foundations, and the first question is whether the gap is still opening.
Guide price from£620per junction inc VAT
- Postcodes
- PL25
- Population
- about 24,000
- Area
- Cornwall
- Pricing region
- South West
Why does the ground in Cornwall matter for extension pulling away repairs?
St Austell (PL25) has around 24,000 residents and sits in Cornwall. Neighbouring towns we cover: Bodmin (9 miles), Truro (13 miles) and Newquay (14 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. What you mostly find across Cornwall: granite and slate-stone cottages, cob buildings, Victorian terraces and post-war estates.
Signs you may need extension pulling away repairs
- Floor level dropping where the extension and house floors meet
- Patio doors or windows in the extension starting to bind
- Daylight or draughts showing through the internal corner joint
How much will extension pulling away repairs cost in St Austell?
These are guide prices for St Austell, using South West rates and including VAT. Your written quote follows photos or a survey, and is fixed once the repair is specified.
| 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 |
Which repair method suits a home in St Austell?
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
What happens when we carry out extension pulling away repairs in St Austell?
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.
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.
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.
Extension pulling away repairs in St Austell: questions and answers
How much will extension pulling away repairs cost in St Austell?
Guide prices for extension pulling away repairs in St Austell 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.
Do you cover St Austell?
Yes. We take enquiries from across St Austell, including PL25, and from nearby places such as Bodmin and Truro. Send photos for a free initial view and we will tell you what happens next.
Is the ground in Cornwall prone to subsidence?
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.
Other structural repairs in St Austell
Extension pulling away repairs near St Austell
Call about the cracked extension junction at your St Austell property; a free initial assessment first, then a fixed written price once the repair is specified.