Gillingham · Kent
Bay window subsidence repairs in Gillingham
Many bays in Gillingham were butted against the house rather than bonded into it with ties or toothed brickwork. That makes the junction the first place any differential movement shows, even when the bay foundation is reasonably sound.
Guide price from£670per bay inc VAT

- Postcodes
- ME7, ME8
- Population
- about 100,000
- Area
- Kent
- Pricing region
- South East
Why does the ground in Kent matter for bay window subsidence repairs?
Gillingham is in Kent and takes in postcode districts ME7, ME8. About 100,000 people live there. Nearby, we also cover Strood (3 miles), Gravesend (8 miles) and Maidstone (9 miles).
Shrinkable clay is widespread in Kent. Parts of Kent lie on a former coalfield, so a coal mining search is worth checking if movement has no obvious cause. Typical buildings 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 Gillingham
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
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
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
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.
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
- A vertical crack where the bay meets the front wall
- Bay roof or lead flashing pulling away from the main wall
- A step or slope in the bay floor towards the window
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 should I budget for bay window subsidence repairs in Gillingham?
Guide prices for bay window subsidence repairs in Gillingham 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.
Can you survey a property in Gillingham?
We do. Gillingham and the surrounding area are covered, including nearby Strood and Gravesend. A free initial assessment from your photos is the first step.
Why do houses in Kent crack?
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.
Will the bay window need replacing?
Usually not. Most windows can be eased, packed or resealed once the bay is stable. If the frame has twisted badly or the glass has cracked, replacement may be worth considering. Under a claim, upgrades beyond like-for-like are normally priced separately.
Related work in Gillingham
Bay window subsidence repairs near Gillingham
Call about the cracked bay at your Gillingham property; a free initial assessment comes first, with a fixed written price once the repair is specified.