Swansea · West Glamorgan
Bay window subsidence repairs in Swansea
Front gardens across Swansea and West Glamorgan often put hedges, trees and gullies close to the bay. Each can affect the ground under a shallow bay footing, so they are checked before deciding between a tie-in repair and underpinning.
Guide price from£550per bay inc VAT

- Postcodes
- SA1, SA2, SA5
- Population
- about 300,000
- Area
- West Glamorgan
- Pricing region
- Wales
What should you know about the ground under Swansea?
With roughly 300,000 people, Swansea spans postcode districts SA1, SA2, SA5 in West Glamorgan. Nearby, we also cover Clydach (5 miles), Gorseinon (5 miles) and Neath (7 miles).
Clay soils are found in parts of West Glamorgan. Historic coal workings are recorded beneath parts of West Glamorgan, and a coal mining search is worth checking where movement is unexplained. Housing stock in West Glamorgan: Hillside terraces, Victorian villas in Swansea and post-war estates.
What should you budget for bay window subsidence repairs in Swansea?
These are guide prices for Swansea, using Wales 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. | £550 – £1,650 | per bay |
| Traditional underpinning of a bay | £2,750 – £6,450 | per bay |
| Mini-piled bay underpinning | £4,600 – £11,000 | per bay |
Repair options we may recommend
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
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
What to expect when we carry out bay window subsidence repairs
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.
Is it time for bay window subsidence repairs? Common signs
- A vertical crack where the bay meets the front wall
- Bay roof or lead flashing pulling away from the main wall
- Bay window sash or casement sticking or binding
Rules for bay window subsidence repairs in Wales
In Wales, the Welsh version of the Building Regulations applies. Underpinning and other work that alters or strengthens the structure needs building control approval and inspection; like-for-like repairs often do not. The Party Wall etc. Act 1996 applies to work on party walls and excavation close to a neighbour’s foundations.
Your bay window subsidence repairs questions
How much should I budget for bay window subsidence repairs in Swansea?
Guide prices for bay window subsidence repairs in Swansea start from about £550 per bay, including VAT, on Wales 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 Swansea?
Yes. We take enquiries from across Swansea, including SA1, SA2, SA5, and from nearby places such as Clydach and Gorseinon. Send photos for a free initial view and we will tell you what happens next.
Why do houses in West Glamorgan crack?
Swansea and Neath Port Talbot lie on the South Wales coalfield, with historic workings, tips and steep valley sides, and softer estuarine ground around the docks. Only an investigation can say why a particular building has moved.
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.
How long does bay underpinning take?
Traditional underpinning of a bay usually takes about a week on site, and mini-piling a little longer depending on depth. A junction tie-in without underpinning normally takes one to two days. Approvals and any monitoring beforehand add to the overall timeline.
Related work in Swansea
- Floor joist repairs
- Concrete repairs
- Subsidence insurance claim repairs
- Gable end wall repairs
- Extension pulling away repairs
Bay window subsidence repairs near Swansea
Call about the cracked bay at your Swansea property; a free initial assessment comes first, with a fixed written price once the repair is specified.