Gwynedd · Wales
Subsidence repairs in Gwynedd
Gwynedd has its own mix of ground and building types, and that shapes how subsidence repairs is done here. Clay shrinkage is less of a concern in Gwynedd, so other causes such as drains, poor footings or older walls are checked first.
Guide price from£2,300per property inc VAT
- Area
- Gwynedd
- Pricing region
- Wales
- Ground
- Mostly firmer ground
- Towns listed
- 6
What is the ground like in Gwynedd?
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.
Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Across Gwynedd, most homes are slate and stone terraces, chapels and cottages, Victorian seaside houses and post-war estates.
Symptoms that point to subsidence repairs
- Diagonal cracks wider at the top, running from window or door corners
- Wallpaper rippling or tearing where the wall meets the ceiling
- Cracks that open in summer and partly close again in winter
- Fresh cracks showing on both the inside and outside of one wall
Guide prices for subsidence repairs in Gwynedd
These are guide prices for Gwynedd, 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 |
|---|---|---|
| Structural engineer's investigation and report | £460 – £1,850 | per property |
| CCTV drain survey (common first check) | £140 – £320 | per survey |
| Typical repair once the cause is dealt with: crack stitching and making goodest. | £2,300 – £11,000 | per property |
| Foundation strengthening where it is needed (see underpinning) | £920 – £3,200 | per metre of wall |
Methods for subsidence repairs
Foundation strengthening
Where the ground cannot be made stable, the load is carried down to firmer soil by underpinning, a beam-and-base scheme, mini-piles or resin injection, depending on the soil and access. It is designed by an engineer and is the exception, not the rule.
Best for: Ongoing movement where removing the cause has not worked
Remove the cause, then repair
Most subsidence is dealt with this way. The drain is repaired or the vegetation managed, the house is watched to confirm it has stabilised, and then the cracks are stitched, repointed and made good inside. It is the least disruptive route and usually the cheapest.
Best for: Clay movement or drain leaks where the cause can be removed
Crack stitching and making good
Once movement has stopped, cracked brickwork is cut along the bed joints, stainless helical bars are bonded in to tie the wall together, and the joints are repointed to match. Inside, plaster is renewed along the crack line before redecoration.
Best for: Category 1 to 3 cracking in walls that are otherwise sound
From first photo to finished repair
Find the cause
An independent chartered structural engineer inspects the house and, where needed, arranges a drain survey, trial pits or soil tests. We can arrange the engineer. The aim is to know what is moving, and why, before money goes on repairs.
Written quote
We price the agreed repair and confirm a fixed price in writing once it is specified. If there is an insurance claim, we can price to the loss adjuster’s or engineer’s schedule instead of our own scope.
Repairs and making good
Cracks are stitched and repointed outside, plaster is renewed along the crack lines inside, and sticking doors are eased. Where the work needs it, we deal with building control and hand over the paperwork.
Do you need approval for 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.
Towns in Gwynedd we cover for subsidence repairs
Frequently asked questions
Is the ground in Gwynedd prone to subsidence?
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. Old metal-mine shafts and workings are recorded in places, so mining searches are routine for some properties. Only an investigation on site can say why a particular building has moved.
How much will subsidence repairs cost in Gwynedd?
On Wales rates, subsidence repairs starts from about £2,300 per property, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.
How long should I wait before repairing subsidence cracks?
Usually until the cause has been dealt with and the engineer is satisfied that movement has stopped. On clay that can mean watching the house through a summer and a winter. Repairing too early risks the same cracks opening again.
Does subsidence always need underpinning?
No, most subsidence is repaired without underpinning. When a leaking drain is fixed or nearby vegetation is managed, the ground usually stabilises and the house needs only crack repairs. Foundation work is kept for movement that continues after the cause has gone.
Do you need to visit before giving a price?
Not at first. We give a free initial assessment from your photos or a call, and a no-obligation written quote once the scope is clear. A fixed price follows in writing once the repair is specified, which normally needs a survey.