County Antrim · Northern Ireland
Extension pulling away repairs in County Antrim
Homes in County Antrim are mostly red-brick terraces in Belfast. That matters for extension pulling away repairs: footings, wall construction and mortar all vary with the age of the building. Most of County Antrim is on firmer ground than the clay belts of the south-east.
Guide price from£530per junction inc VAT

- Area
- County Antrim
- Pricing region
- Northern Ireland
- Ground
- Mostly firmer ground
- Towns listed
- 8
How do local ground conditions affect extension pulling away repairs in County Antrim?
County Antrim is largely basalt over chalk, with soft estuarine 'sleech' along Belfast Lough that is notorious for settlement. Historic salt mining is recorded near Carrickfergus.
Historic brine and salt working has caused ground movement in parts of County Antrim in the past. Across County Antrim, most homes are red-brick terraces in Belfast, Victorian villas, and post-war and newer estates.
Which repair method suits a home in County Antrim?
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
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
What happens when we carry out extension pulling away repairs in County Antrim?
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.
Choose the fix
The engineer decides between ties, a movement joint or underpinning. We confirm a fixed price in writing once the repair is specified, covering the junction, flashings, internal finishes and any foundation work.
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.
Signs you may need extension pulling away repairs
- Daylight or draughts showing through the internal corner joint
- Extension roof flashing lifting off the original wall
- Mastic or render at the joint repeatedly splitting open
- Patio doors or windows in the extension starting to bind
How much will extension pulling away repairs cost in County Antrim?
For County Antrim we use Northern Ireland 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 |
|---|---|---|
| Junction crack repair with stainless tiesest. | £530 – £1,750 | per junction |
| Movement joint and making goodest. | £350 – £1,050 | per junction |
| Underpinning the extension where needed | £880 – £2,200 | per metre of wall |
Do you need approval for extension pulling away repairs in Northern Ireland?
In Northern Ireland, the Building Regulations (Northern Ireland) 2012 apply and the council’s building control service approves structural work such as underpinning; minor like-for-like repairs usually need no approval. The Party Wall Act does not apply in Northern Ireland, so work to shared walls depends on deeds and agreement with neighbours.
Find extension pulling away repairs in your County Antrim town
Extension pulling away repairs in County Antrim: questions and answers
Why do houses in County Antrim crack?
County Antrim is largely basalt over chalk, with soft estuarine 'sleech' along Belfast Lough that is notorious for settlement. Historic salt mining is recorded near Carrickfergus. Historic brine and salt working has caused ground movement in parts of County Antrim in the past. Only an investigation on site can say why a particular building has moved.
How much will extension pulling away repairs cost in County Antrim?
On Northern Ireland rates, extension pulling away repairs starts from about £530 per junction, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.
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.
Why is my extension pulling away from my house?
Usually because the extension and the house sit on different foundations that react differently to the ground. Shallow extension footings, leaking drains under the extension, nearby roots and weak tie-ins between old and new walls are the common causes.
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.