Lincolnshire · England
Bay window subsidence repairs in Lincolnshire
Looking for bay window subsidence repairs in Lincolnshire? Send us photos for a free initial view. Clay soils are found in parts of Lincolnshire, so we look at the ground, drains and nearby trees before recommending anything.
Guide price from£590per bay inc VAT

- Area
- Lincolnshire
- Pricing region
- East Midlands
- Ground
- Clay in parts
- Towns listed
- 11
Why does the ground in Lincolnshire matter for bay window subsidence repairs?
Lincolnshire has Lias, Oxford and Kimmeridge clays on the vales, chalk on the Wolds and soft silts and peat in the fens around Boston and Spalding. Fen ground and clay can both settle or shrink in dry years.
Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across Lincolnshire: Victorian terraces in Lincoln and Grimsby, fenland brick houses, seaside bungalows and post-war estates.
How we usually approach 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
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
What happens during bay window subsidence repairs, step by step?
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.
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.
What to look for before calling about bay window subsidence repairs
- Gaps opening around the internal bay window board
- Bay roof or lead flashing pulling away from the main wall
- Bay window sash or casement sticking or binding
- A vertical crack where the bay meets the front wall
Bay window subsidence repairs prices in Lincolnshire
Prices in Lincolnshire are worked out on East Midlands 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. | £590 – £1,750 | per bay |
| Traditional underpinning of a bay | £2,950 – £6,850 | per bay |
| Mini-piled bay underpinning | £4,900 – £11,800 | per bay |
Do you need approval 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.
Bay window subsidence repairs near you in Lincolnshire
Questions about bay window subsidence repairs in Lincolnshire
Does the ground around Lincoln cause cracking?
Lincolnshire has Lias, Oxford and Kimmeridge clays on the vales, chalk on the Wolds and soft silts and peat in the fens around Boston and Spalding. Fen ground and clay can both settle or shrink in dry years. Ground movement here is more often linked to soils, drains and trees than to mining. Only an investigation on site can say why a particular building has moved.
How much will bay window subsidence repairs cost in Lincolnshire?
On East Midlands rates, bay window subsidence repairs starts from about £590 per bay, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.
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.
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 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.