St Albans · Hertfordshire
Extension pulling away repairs in St Albans
Rear and side extensions are common across St Albans, and so is the crack where new meets old. Usually it reflects the two parts sitting on different foundations, and the first question is whether the gap is still opening.
Guide price from£630per junction inc VAT

- Postcodes
- AL1, AL2
- Population
- about 85,000
- Area
- Hertfordshire
- Pricing region
- East of England
How do local ground conditions affect extension pulling away repairs in St Albans?
Postcode districts AL1, AL2 cover St Albans, a Hertfordshire town of about 85,000 people. Nearby, we also cover Harpenden (5 miles), Hatfield (5 miles) and Hemel Hempstead (5 miles).
Shrinkable clay is widespread in Hertfordshire. Ground movement here is more often linked to soils, drains and trees than to mining. Typical buildings in Hertfordshire: Garden-city houses in Letchworth and Welwyn, 1930s semis, Victorian terraces and post-war new-town estates.
What to expect when we carry out extension pulling away repairs
Find what is moving
An independent chartered structural engineer can inspect, and we can arrange one. A drain survey under the extension, a trial pit at its footing and tell-tale monitoring across the joint are common checks before choosing the repair.
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.
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.
Is it time for extension pulling away repairs? Common signs
- Daylight or draughts showing through the internal corner joint
- A vertical crack or gap where the extension meets the house
- Floor level dropping where the extension and house floors meet
What should you budget for extension pulling away repairs in St Albans?
These are guide prices for St Albans, using East of England rates and including VAT. Your written quote follows photos or a survey, and is fixed once the repair is specified.
| Item | Guide price | Per |
|---|---|---|
| Junction crack repair with stainless tiesest. | £630 – £2,100 | per junction |
| Movement joint and making goodest. | £420 – £1,250 | per junction |
| Underpinning the extension where needed | £1,050 – £2,600 | per metre of wall |
Repair options we may recommend
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
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
Rules for extension pulling away repairs in England
In England, underpinning and other work that alters or strengthens a wall or foundation is building work under the Building Regulations (Part A, structure), so building control approves and inspects it. Like-for-like repairs often are not, and we tell you which applies before a price is agreed. Work to a party wall, or excavation close to a neighbour’s foundations, can also need a notice under the Party Wall etc. Act 1996.
Your extension pulling away repairs questions
How much will extension pulling away repairs cost in St Albans?
Guide prices for extension pulling away repairs in St Albans start from about £630 per junction, including VAT, on East of England rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you cover St Albans?
Yes, St Albans is covered, along with postcode districts AL1, AL2. We also cover nearby Harpenden and Hatfield.
Is the ground in Hertfordshire prone to subsidence?
South Hertfordshire around Watford, Borehamwood and Potters Bar is London Clay, while the north and west are chalk with clay-with-flints and the east has boulder clay. The clay areas are prone to seasonal subsidence near trees. Only an investigation can say why a particular building has moved.
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.
Who is responsible if a recent extension is moving?
If the extension is recent, the original builder, the designer or building control records may be relevant, and you may have rights against the builder. Gather the plans, completion certificate and contract. Insurance often excludes defects in new construction, so check your policy.
Other structural repairs in St Albans
- Subsidence repairs
- Subsidence insurance claim repairs
- Retaining wall repairs
- Crack stitching
- Boundary and garden wall repairs
Extension pulling away repairs near St Albans
Share the loss adjuster’s schedule for your St Albans extension claim, and we will price the junction repair and making good to it in writing.