Extension pulling away repairs in Kent

Area: Kent
Pricing region: South East
Ground: Shrinkable clay widespread
Towns listed: 22

What is the ground like in Kent?

Parts of Kent lie on a former coalfield, so a coal mining search is worth checking if movement has no obvious cause. Across Kent, most homes are Victorian terraces in the Medway towns, weatherboarded and Wealden houses, 1930s semis and seaside bungalows.

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

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.
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.

Is it time for extension pulling away repairs? Common signs

A vertical crack or gap where the extension meets the house
Patio doors or windows in the extension starting to bind
Extension roof flashing lifting off the original wall
Mastic or render at the joint repeatedly splitting open

What should you budget for extension pulling away repairs in Kent?

Prices in Kent are worked out on South East rates. They include VAT and are a starting point: access, the extent of the damage and whether an engineer or building control is involved all move the figure.

Guide prices inc VAT on South East rates. Items marked est. are our estimates.
Item	Guide price	Per
Junction crack repair with stainless tiesest.	£670 – £2,250	per junction
Movement joint and making goodest.	£450 – £1,350	per junction
Underpinning the extension where needed	£1,100 – £2,800	per metre of wall

Extension pulling away: tapered gap at the junction tied in with stainless bars. Indicative drawing, not to scale.

Do you need approval 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.

Towns in Kent we cover for extension pulling away repairs

Your extension pulling away repairs questions

Is the ground in Kent prone to subsidence?

North Kent sits on London Clay, central Kent on Gault and Weald Clays and the Downs on chalk, so shrinkable clay is widespread. East Kent around Deal and Dover had a small deep coalfield, worked until the late 1980s. Parts of Kent 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 Kent?

On South East rates, extension pulling away repairs starts from about £670 per junction, including VAT. The written price depends on the extent of the damage, access and whether an engineer or building control is needed.

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.

Is it normal for an extension to crack at the join?

A fine crack at the junction is fairly common, especially in the first few years as a new extension settles. It becomes a concern when the gap is widening, tapering, letting in water or matched by sticking doors and sloping floors. Those signs point to continuing movement.

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.