Swindon · Wiltshire
Bay window subsidence repairs in Swindon
Front gardens across Swindon and Wiltshire often put hedges, trees and gullies close to the bay. Each can affect the ground under a shallow bay footing, so they are checked before deciding between a tie-in repair and underpinning.
Guide price from£620per bay inc VAT

- Postcodes
- SN1, SN2, SN3
- Population
- about 200,000
- Area
- Wiltshire
- Pricing region
- South West
What is the ground like in Wiltshire?
We cover Swindon and its postcode districts SN1, SN2, SN3, part of Wiltshire, with a population of roughly 200,000. Nearby, we also cover Calne (13 miles), Cirencester (14 miles) and Carterton (16 miles).
Parts of Wiltshire have clay that can shrink near trees in dry spells. Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across Wiltshire: stone cottages, railway terraces in Swindon, and large post-war and new-build estates.
Is it time for bay window subsidence repairs? Common signs
- A step or slope in the bay floor towards the window
- Gaps opening around the internal bay window board
- A vertical crack where the bay meets the front wall
What should you budget for bay window subsidence repairs in Swindon?
Prices in Swindon are worked out on South West 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 |
|---|---|---|
| Bay junction crack repair and tie-inest. | £620 – £1,850 | per bay |
| Traditional underpinning of a bay | £3,100 – £7,200 | per bay |
| Mini-piled bay underpinning | £5,150 – £12,400 | per bay |
Repair options we may recommend
Junction crack repair and tie-in
Where movement has stopped, the open joint between bay and house is raked out, stainless ties or helical bars are fixed across it, and the joint is repointed to match. Internal plaster along the crack is cut back and renewed before redecoration.
Best for: Old, stable cracks where the bay is no longer moving
Mini-piled bay underpinning
Small piles are installed to depth around or beneath the bay and linked by a reinforced beam or needles that pick up its weight. It suits deeper soft ground and heavy root activity, and the compact rigs fit into a front garden.
Best for: Deep clay, nearby trees, or poor ground below the bay
What to expect when we carry out bay window subsidence repairs
Engineer and checks
Where the cause is unclear, an independent chartered structural engineer inspects, sometimes with a trial pit at the bay and a drain survey. We can arrange the engineer. Monitoring may be suggested if the movement could be seasonal.
Agree the repair
The engineer decides between tie-in repairs and underpinning. We confirm a fixed price in writing once the repair is specified, including scaffolding if needed, the bay window, roof flashing and internal making good.
Carry out the work
Ties are fitted across the junction, or the bay is underpinned in sequence with building control inspecting the dig. The bay window and flashings are checked and eased or resealed where the movement has disturbed them.
Rules for bay window subsidence 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 bay window subsidence repairs questions
How much should I budget for bay window subsidence repairs in Swindon?
Guide prices for bay window subsidence repairs in Swindon start from about £620 per bay, 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 Swindon?
Yes. We take enquiries from across Swindon, including SN1, SN2, SN3, and from nearby places such as Calne and Cirencester. Send photos for a free initial view and we will tell you what happens next.
Why do houses in Wiltshire crack?
Southern Wiltshire is chalk, while the north around Swindon, Chippenham and Trowbridge sits on Oxford and Kimmeridge Clays that are prone to seasonal movement near trees. Bath stone was mined underground around Corsham. Only an investigation can say why a particular building has moved.
Why do bay windows crack away from the house?
Bays often stand on shallower footings than the main walls, so they react to drying clay, roots and drain leaks that the deeper house foundations escape. Many bays were also never properly tied in, so any movement opens a clean vertical crack at the junction.
Can I just fill the crack myself?
Filling it hides the evidence without dealing with the cause, and if the bay is still moving the crack will reopen. Photograph it with a scale and date first. If you plan to claim on insurance, tell your insurer before any repair, including filling.
Related work in Swindon
Bay window subsidence repairs near Swindon
Send photos of the bay junction inside and out at your Swindon home for a free initial assessment and a guide price.