Falmouth · Cornwall
Bay window subsidence repairs in Falmouth
Many bays in Falmouth 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£620per bay inc VAT

- Postcodes
- TR11
- Population
- about 32,000
- Area
- Cornwall
- Pricing region
- South West
Is Cornwall prone to ground movement?
Falmouth is in Cornwall and takes in postcode districts TR11. About 32,000 people live there. Nearby places we cover include Truro (8 miles), Redruth (9 miles) and Camborne (11 miles).
Clay shrinkage is less of a concern in Cornwall, so other causes such as drains, poor footings or older walls are checked first. Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Across Cornwall, most homes are granite and slate-stone cottages, cob buildings, Victorian terraces and post-war estates.
How we usually approach bay window subsidence repairs
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
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 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.
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.
What to look for before calling about bay window subsidence repairs
- Cracks above the bay window head or below the sill
- A vertical crack where the bay meets the front wall
- A step or slope in the bay floor towards the window
Bay window subsidence repairs prices in Falmouth
Prices in Falmouth 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 |
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.
Questions about bay window subsidence repairs in Falmouth
How much should I budget for bay window subsidence repairs in Falmouth?
Guide prices for bay window subsidence repairs in Falmouth 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 Falmouth?
Yes. We take enquiries from across Falmouth, including TR11, and from nearby places such as Truro and Redruth. Send photos for a free initial view and we will tell you what happens next.
Why do houses in Cornwall crack?
Cornwall is mostly granite and slate with little shrinkable clay, so clay subsidence is less common than in the south-east. Historic tin and copper mining has left shafts and workings in places such as Camborne and Redruth, and mining searches are routine there. 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 Falmouth
- Bowing wall repairs
- Lintel replacement
- Wall tie replacement
- Subsidence insurance claim repairs
- Structural crack repairs
Bay window subsidence repairs near Falmouth
For a no-obligation written quote on bay window subsidence in Falmouth, call or send a few photos with a tape measure in shot.