Harrow · Greater London
Underpinning in Harrow
Before any underpinning goes ahead on a Harrow 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
- HA1, HA2, HA3, HA5, HA6
- Population
- about 260,000
- Area
- Greater London
- Pricing region
- London
Is Greater London prone to ground movement?
Harrow takes in postcode districts including HA1, HA2, HA3, HA5, HA6, with about 260,000 residents. Nearby, we also cover Brent (3 miles), Ealing (5 miles) and Borehamwood (5 miles).
Greater London is one of the parts of the UK where clay soils are most likely to move with the seasons. Ground movement here is more often linked to soils, drains and trees than to mining. What you mostly find across Greater London: Victorian and Edwardian terraces with shallow footings, inter-war semis in the outer boroughs, and converted flats and mansion blocks.
Methods for underpinning
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
Mass concrete underpinning
The traditional method. Short sections under the wall are dug out in a set sequence, usually about a metre at a time, and filled with concrete before the next section is opened. It suits moderate depths and good access, and it needs little specialist plant.
Best for: Shallow failures on firm ground found at moderate depth
From first photo to finished repair
Engineer’s investigation
An independent chartered structural engineer studies the monitoring results, trial pits and soil tests, then decides whether underpinning is needed and which method suits. We can arrange the engineer if you do not already have one.
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.
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.
Symptoms that point to underpinning
- Footings found to be very shallow during a trial pit
- Cracks that keep widening after the drains have been repaired
- Movement continuing through more than one winter of monitoring
Guide prices for underpinning in Harrow
These are guide prices for Harrow, 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 |
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.
Frequently asked questions
What is the price of underpinning in Harrow?
Guide prices for underpinning in Harrow 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 Harrow?
Yes, Harrow is covered, along with postcode districts HA1, HA2, HA3, HA5. We also cover nearby Brent and Ealing.
Does the ground around Harrow 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.
Do I need to tell my neighbours about underpinning?
In England and Wales you usually do. Underpinning a party wall normally needs two months’ notice, and excavating near a neighbour’s foundations needs one month’s notice under the Party Wall etc. Act 1996. Scotland and Northern Ireland have no equivalent Act, but agreeing the work in writing still helps.
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 Harrow
- Bowing wall repairs
- Subsidence repairs
- Floor joist repairs
- Extension pulling away repairs
- Concrete repairs
Underpinning near Harrow
Start with photos and a short description of the movement at your Harrow property; we will reply with a free initial assessment and the next step.