Caernarfon · Gwynedd
Bay window subsidence repairs in Caernarfon
Repairing a subsiding bay in Caernarfon usually involves one of three routes: tie the junction, underpin with concrete, or install mini-piles. The engineer picks the route from the ground and the movement history, and we price it in writing.
Guide price from£550per bay inc VAT
- Postcodes
- LL55
- Population
- about 10,000
- Area
- Gwynedd
- Pricing region
- Wales
What should you know about the ground under Caernarfon?
Caernarfon (LL55) has around 10,000 residents and sits in Gwynedd. We also take enquiries from nearby Llangefni (8 miles), Bangor (9 miles) and Pwllheli (18 miles).
Clay shrinkage is less of a concern in Gwynedd, 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. What you mostly find across Gwynedd: slate and stone terraces, chapels and cottages, Victorian seaside houses and post-war estates.
Is it time for bay window subsidence repairs? Common signs
- Cracks above the bay window head or below the sill
- Bay window sash or casement sticking or binding
- A vertical crack where the bay meets the front wall
What should you budget for bay window subsidence repairs in Caernarfon?
For Caernarfon we use Wales rates. Treat the table as a budget guide, inc VAT; the price you pay is the one on your written quote.
| 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
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
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
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.
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.
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
What is the price of bay window subsidence repairs in Caernarfon?
Guide prices for bay window subsidence repairs in Caernarfon 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.
Do you carry out bay window subsidence repairs in Caernarfon?
Yes, Caernarfon is covered, along with postcode districts LL55. We also cover nearby Llangefni and Bangor.
Does the ground around Caernarfon cause cracking?
Gwynedd and Anglesey are mostly hard rock with glacial deposits, so clay shrinkage is uncommon. Historic slate quarrying and metal mining have left tips and workings in places. Only an investigation can say why a particular building has moved.
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.
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.
More repairs we carry out in Caernarfon
- Retaining wall repairs
- Resin injection ground stabilisation
- Structural crack repairs
- Gable end wall repairs
- Subsidence repairs
Bay window subsidence repairs near Caernarfon
Not sure whether your Caernarfon bay is still moving? Send dated photos, and we will suggest whether monitoring or a repair comes next.