Deal · Kent
Bay window subsidence repairs in Deal
If your Deal bay window has started sticking and a gap has opened at the junction, it is worth finding out whether the bay is still moving. A stable crack needs a straightforward tie-in, whereas an active one may need a new foundation.
Guide price from£670per bay inc VAT

- Postcodes
- CT14
- Population
- about 31,000
- Area
- Kent
- Pricing region
- South East
How do local ground conditions affect bay window subsidence repairs in Deal?
Postcode districts CT14 cover Deal, a Kent town of about 31,000 people. We also take enquiries from nearby Dover (8 miles), Ramsgate (8 miles) and Margate (11 miles).
Kent is one of the parts of the UK where clay soils are most likely to move with the seasons. Parts of Kent lie on a former coalfield, so a coal mining search is worth checking if movement has no obvious cause. Housing stock in Kent: Victorian terraces in the Medway towns, weatherboarded and Wealden houses, 1930s semis and seaside bungalows.
Guide prices for bay window subsidence repairs in Deal
The ranges below reflect typical South East costs for bay window subsidence repairs, including VAT. Scaffold, access and making good can push a job to the top of the range.
| Item | Guide price | Per |
|---|---|---|
| Bay junction crack repair and tie-inest. | £670 – £2,000 | per bay |
| Traditional underpinning of a bay | £3,350 – £7,850 | per bay |
| Mini-piled bay underpinning | £5,600 – £13,400 | per bay |
Methods for bay window subsidence repairs
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
Traditional underpinning of the bay
The bay footing is excavated in short sections and new mass concrete is placed down to firmer ground below the zone affected by roots and seasons. Because a bay is a short length of wall, the work is compact, but it needs building control approval.
Best for: Active bay movement on firm ground at moderate depth
From first photo to finished repair
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.
Make good inside
Plaster around the bay and along the junction is renewed, the window board is refixed and the room is ready for decoration. Building control paperwork, where it applies, is passed to you for your records.
Symptoms that point to bay window subsidence repairs
- Gaps opening around the internal bay window board
- Bay window sash or casement sticking or binding
- Bay roof or lead flashing pulling away from the main wall
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.
Frequently asked questions
How much will bay window subsidence repairs cost in Deal?
Guide prices for bay window subsidence repairs in Deal start from about £670 per bay, including VAT, on South East rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you cover Deal?
Yes. We take enquiries from across Deal, including CT14, and from nearby places such as Dover and Ramsgate. Send photos for a free initial view and we will tell you what happens next.
Is the ground in Kent prone to subsidence?
North Kent sits on London Clay, central Kent on Gault and Weald Clays and the Downs on chalk, so shrinkable clay is widespread. East Kent around Deal and Dover had a small deep coalfield, worked until the late 1980s. Only an investigation can say why a particular building has moved.
Can a bay be underpinned without underpinning the house?
Yes, underpinning only the bay is common because it is usually the part on shallower footings. The engineer designs the junction so the strengthened bay and the existing house can move slightly without cracking, sometimes with a movement joint or ties.
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.
Other structural repairs in Deal
- Resin injection ground stabilisation
- Brick arch repairs
- Lintel replacement
- Underpinning
- Boundary and garden wall repairs
Bay window subsidence repairs near Deal
Photos of the bay floor, window and junction crack are enough to start; send them about your Deal home and we will reply with a view.