Hertford · Hertfordshire
Extension pulling away repairs in Hertford
If the corner joint in your Hertford extension keeps splitting after you fill it, something is still moving. Measuring the gap over a few months, with dated photos, gives an engineer the evidence to recommend the right repair.
Guide price from£630per junction inc VAT

- Postcodes
- SG13, SG14
- Population
- about 26,000
- Area
- Hertfordshire
- Pricing region
- East of England
What should you know about the ground under Hertford?
With roughly 26,000 people, Hertford spans postcode districts SG13, SG14 in Hertfordshire. We also take enquiries from nearby Ware (2 miles), Hoddesdon (4 miles) and Welwyn Garden City (6 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.
From first photo to finished repair
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.
Symptoms that point to extension pulling away repairs
- Floor level dropping where the extension and house floors meet
- Patio doors or windows in the extension starting to bind
- Daylight or draughts showing through the internal corner joint
Guide prices for extension pulling away repairs in Hertford
For Hertford we use East of England 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. | £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 |
Methods for extension pulling away repairs
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
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.
Frequently asked questions
How much will extension pulling away repairs cost in Hertford?
Guide prices for extension pulling away repairs in Hertford 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 Hertford?
Yes, Hertford is covered, along with postcode districts SG13, SG14. We also cover nearby Ware and Hoddesdon.
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.
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.
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 Hertford
- Wall tie replacement
- Roof structure repairs
- Crack stitching
- Subsidence insurance claim repairs
- Bay window subsidence repairs
Extension pulling away repairs near Hertford
Share the loss adjuster’s schedule for your Hertford extension claim, and we will price the junction repair and making good to it in writing.