Bexley · Greater London
Bay window subsidence repairs in Bexley
If your Bexley 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£750per bay inc VAT

- Postcodes
- DA5, DA6, DA7, DA8, DA14
- Population
- about 250,000
- Area
- Greater London
- Pricing region
- London
What should you know about the ground under Bexley?
Bexley is one of the 32 London boroughs, with around 250,000 residents in districts such as DA5, DA6, DA7, DA8, DA14. Neighbouring towns we cover: Dartford (3 miles), Swanley (4 miles) and Greenwich (4 miles).
Shrinkable clay is widespread in Greater London. Ground movement here is more often linked to soils, drains and trees than to mining. Typical buildings in Greater London: Victorian and Edwardian terraces with shallow footings, inter-war semis in the outer boroughs, and converted flats and mansion blocks.
Guide prices for bay window subsidence repairs in Bexley
These are guide prices for Bexley, using London rates and including VAT. Your written quote follows photos or a survey, and is fixed once the repair is specified.
| Item | Guide price | Per |
|---|---|---|
| Bay junction crack repair and tie-inest. | £750 – £2,250 | per bay |
| Traditional underpinning of a bay | £3,750 – £8,750 | per bay |
| Mini-piled bay underpinning | £6,250 – £15,000 | 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
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
From first photo to finished repair
Photos and first view
Send photos of the outside junction, the inside corners and the window, with a scale. We give a free initial assessment and tell you whether the crack looks old and stable or whether an engineer should inspect first.
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.
Symptoms that point to bay window subsidence repairs
- Bay window sash or casement sticking or binding
- Gaps opening around the internal bay window board
- Cracks above the bay window head or below the sill
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 Bexley?
Guide prices for bay window subsidence repairs in Bexley start from about £750 per bay, including VAT, on London rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you cover Bexley?
We do. Bexley and the surrounding area are covered, including nearby Dartford and Swanley. A free initial assessment from your photos is the first step.
Is the ground in Greater London prone to subsidence?
Most of Greater London sits on London Clay, among the most shrinkage-prone ground in the UK, with river gravels along the Thames. Subsidence claims here are among the most frequent in the country, especially after dry summers and near street and garden trees. Only an investigation can say why a particular building has moved.
Is a crack between my bay and the house serious?
It is often not serious, especially if it is old, fine and unchanged for years. A crack that is widening, tapering or matched by sticking windows and a sloping bay floor needs looking at. An engineer’s inspection, sometimes with monitoring, will confirm whether the bay is still moving.
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 Bexley
- Bowing wall repairs
- Gable end wall repairs
- Subsidence insurance claim repairs
- Chimney stack repairs
- Boundary and garden wall repairs
Bay window subsidence repairs near Bexley
Call about the cracked bay at your Bexley property; a free initial assessment comes first, with a fixed written price once the repair is specified.