Merton · Greater London
Underpinning in Merton
Before any underpinning goes ahead on a Merton property, building control has to approve the design and inspect the excavations. Where the wall is shared, party wall notices may be needed too in England and Wales, so allow time for paperwork before the dig.
Guide price from£1,250per metre of wall inc VAT
- Postcodes
- CR4, SM4, SW19, SW20
- Population
- about 220,000
- Area
- Greater London
- Pricing region
- London
What should you know about the ground under Merton?
Merton takes in postcode districts including CR4, SM4, SW19, SW20, with about 220,000 residents. Nearby places we cover include Wandsworth (3 miles), Sutton (3 miles) and Kingston upon Thames (4 miles).
Much of Greater London sits on clay that shrinks in dry summers and swells in wet winters. Ground movement here is more often linked to soils, drains and trees than to mining. Housing stock in Greater London: Victorian and Edwardian terraces with shallow footings, inter-war semis in the outer boroughs, and converted flats and mansion blocks.
What to look for before calling about underpinning
- Floors sloping noticeably towards one external wall
- One corner of the house visibly lower than the others
- A large tree nearby that cannot be removed or reduced
Underpinning prices in Merton
These are guide prices for Merton, using London rates and including VAT. Your written quote follows photos or a survey, and is fixed once the repair is specified.
| Item | Guide price | Per |
|---|---|---|
| Mass-concrete underpinning | £1,250 – £1,900 | per metre of wall |
| Beam-and-base underpinning | £1,900 – £3,100 | per metre of wall |
| Mini-piled underpinning | £2,500 – £4,400 | per metre of wall |
| Engineer's design and building control feesest. | £1,000 – £3,100 | per scheme |
How we usually approach underpinning
Beam-and-base underpinning
A reinforced concrete beam is cast beneath or alongside the existing footing and carries the wall onto mass concrete bases at intervals. It spreads load well across variable ground and can mean less digging than continuous underpinning along the whole wall.
Best for: Longer runs of wall or heavier loads over variable ground
Mini-piled underpinning
Small-diameter piles are driven or bored down to firm ground and linked by a reinforced beam or needles that pick up the wall. Compact rigs fit through narrow access, and the method reaches depths that would be impractical to excavate by hand.
Best for: Deep soft ground, tree roots, or restricted access
What happens during underpinning, step by step?
Fixed written price
With the design in hand we confirm a fixed price in writing, setting out the method, the length of wall, access arrangements and the making good. For insurance work we can price to the loss adjuster’s or engineer’s schedule.
Excavation and concrete
Work runs in the sequence the engineer sets so the wall is never left unsupported over a long length. Building control inspects the excavations before concrete goes in, and each section is dry-packed tight to the footing above.
Crack repairs and handover
Once the new foundation has cured, cracks are stitched and repointed, inside walls are made good, and paths or patios disturbed by the dig are reinstated. You receive the building control completion paperwork for your records.
Rules for underpinning 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.
Questions about underpinning in Merton
What is the price of underpinning in Merton?
Guide prices for underpinning in Merton start from about £1,250 per metre of wall, including VAT, on London rates. Your fixed written price follows photos or a survey and depends on the extent of the work and access.
Do you carry out underpinning in Merton?
We do. Merton and the surrounding area are covered, including nearby Wandsworth and Sutton. A free initial assessment from your photos is the first step.
Does the ground around Merton cause cracking?
Most of Greater London sits on London Clay, among the most shrinkage-prone ground in the UK, with river gravels along the Thames. Subsidence claims here are among the most frequent in the country, especially after dry summers and near street and garden trees. Only an investigation can say why a particular building has moved.
Does my house really need underpinning?
Often not, because most subsidence is fixed by repairing drains or managing trees and then repairing the cracks. Underpinning is justified when monitoring shows movement continuing after the cause has been dealt with, or when the ground itself is unsuitable. An independent engineer should make that call.
Can I stay in my house during underpinning?
Most people stay at home during external underpinning, because the digging happens outside along the wall. Expect noise, restricted access to that side of the house and some dust. If the work has to be done from inside, through the floor, moving out for part of the job is sometimes advised.
More repairs we carry out in Merton
- Crack stitching
- Subsidence insurance claim repairs
- Chimney stack repairs
- Roof structure repairs
- Concrete repairs
Underpinning near Merton
Have an engineer’s underpinning design for your Merton property? Send it over and we will return a fixed price in writing once the scheme is specified.