Clwyd · Wales
Extension pulling away repairs in Clwyd
We carry out extension pulling away repairs across Clwyd, from the larger towns to smaller places nearby. Clwyd has a mix of ground, with clay in some places and firmer rock in others. Every job starts with the cause, then the repair is specified to match it.
Guide price from£550per junction inc VAT

- Area
- Clwyd
- Pricing region
- Wales
- Ground
- Clay in parts
- Towns listed
- 9
Why does the ground in Clwyd matter for extension pulling away repairs?
The North Wales coalfield runs beneath parts of Wrexham and Flintshire, where historic workings are recorded, while the coast and vale have glacial clays and the hills are older hard rock.
Parts of Clwyd lie on a former coalfield, so a coal mining search is worth checking if movement has no obvious cause. Housing stock in Clwyd: Brick colliery terraces, seaside villas in Rhyl and Colwyn Bay, and post-war estates.
Is it time for extension pulling away repairs? Common signs
- Mastic or render at the joint repeatedly splitting open
- Floor level dropping where the extension and house floors meet
- Patio doors or windows in the extension starting to bind
- Extension roof flashing lifting off the original wall
What should you budget for extension pulling away repairs in Clwyd?
The ranges below reflect typical Wales costs for extension pulling away repairs, including VAT. Scaffold, access and making good can push a job to the top of the range.
| Item | Guide price | Per |
|---|---|---|
| Junction crack repair with stainless tiesest. | £550 – £1,850 | per junction |
| Movement joint and making goodest. | £370 – £1,100 | per junction |
| Underpinning the extension where needed | £920 – £2,300 | per metre of wall |
Repair options we may recommend
Junction crack repair with stainless ties
The open joint is cut out, stainless ties or helical bars are fixed across it into both the old and new masonry, and the joint is repointed or rendered to match. Inside, the corner is replastered. This suits extensions that moved once and have since stopped.
Best for: Settled extensions with a stable gap at the junction
Movement joint and making good
Where some seasonal movement is expected to continue, the junction is formed into a proper flexible movement joint with a compressible filler and sealant, so the two parts can move without cracking. Flashings and internal finishes are detailed to suit.
Best for: Minor ongoing movement that does not threaten the structure
Underpinning the extension
If the extension is still dropping because its footings are too shallow or on poor ground, they are taken deeper by mass concrete, beam-and-base or mini-piles. The engineer designs the scheme, and the junction is repaired once the new foundation is in.
Best for: Active movement from shallow footings, roots or soft ground
What to expect when we carry out extension pulling away repairs
Show us the junction
Send photos of the crack outside, the internal corner and any flashing above, with a measure for scale. We give a free initial assessment and an initial view on whether the gap is likely old or still opening.
Repair the junction
Drains are repaired first if they are leaking. The joint is then tied, formed as a movement joint or rebuilt after underpinning, with roof flashings reset so the junction stays watertight. Building control is handled where needed.
Finish and hand over
Internal corners are replastered, skirtings and coving refixed, and doors or windows in the extension eased where the movement affected them. Records of the repair and any approvals are passed to you.
Do you need approval for extension pulling away 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 Clwyd we cover for extension pulling away repairs
Your extension pulling away repairs questions
Is the ground in Clwyd prone to subsidence?
The North Wales coalfield runs beneath parts of Wrexham and Flintshire, where historic workings are recorded, while the coast and vale have glacial clays and the hills are older hard rock. Parts of Clwyd lie on a former coalfield, so a coal mining search is worth checking if movement has no obvious cause. Only an investigation on site can say why a particular building has moved.
How much will extension pulling away repairs cost in Clwyd?
On Wales rates, extension pulling away repairs starts from about £550 per junction, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.
Will my extension need underpinning?
Often not. Many separating extensions are fixed by repairing a drain, tying the junction or forming a movement joint. Underpinning is for extensions that keep dropping because their footings are too shallow or the ground beneath is poor, as shown by monitoring.
Can a drain under my extension cause it to move?
Yes, a cracked or displaced drain beneath or beside an extension can soften clay or wash away fine soil. A CCTV drain survey usually finds it. Repairing the drain is often the first and most important step before any repair to the walls.
Can I just fill the gap with mastic?
Mastic can keep water out short term, but it does not stop movement or reconnect the walls. If the gap reopens after filling, something is still moving. Photograph and measure it over a few months first, so an engineer can see the trend.