Basement specialistsin Clapham ,SW4 & Old Town.
Basement excavations, conversions and waterproofing across Clapham: Old Town, The Chase, Abbeville Village, Clapham Park, Clapham North and Clapham South.
Our own 25-strong team · Free site visit and quote · 25-year warranty.
We know Clapham's terraces and party walls.
Clapham is defined by its tightly-packed Victorian mid-terraces, three-storey, four-bedroom homes with cellars, standing shoulder to shoulder from The Chase down to Abbeville Village and out to Clapham Park. That density is why we've completed more than twenty-five basements in SW4 in the last decade, and why we handle Party Wall Awards for Clapham streets almost every week.
All SW4 postcodes and adjoining SW11, SW12 and SW9. Deepest coverage in Old Town, The Chase, Abbeville Village, Clapham Common North & South Sides, Clapham Park and Clapham North.
Call or email and a director will get back to you to arrange a free site visit at a time that suits you.
Victorian mid-terrace and end-terrace family houses, converted flats over shops on Abbeville and Clapham High Street, Edwardian mansion blocks, and modern conversions around Clapham Common.
Full basement excavations for kitchen-diners under four-bed terraces, cellar conversions off Abbeville Road, Type C cavity drainage retrofits on flood-prone streets near the Common, and light wells to open up deep, dark rear rooms.
Every basement discipline, under one roof.
Every UHM basement discipline is delivered across Clapham. Each service link below explains the technical detail, materials, warranties and what's included on a typical SW4 job.
Basement Excavation
New basements dug and structurally formed beneath Clapham homes, sequenced underpinning for Victorian brick.
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Basement Conversion
Fully habitable Clapham lower-ground floors, kitchens, cinemas, guest suites, matched ceiling heights.
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Waterproofing & Tanking
BS 8102 Type C cavity drainage across Clapham, Delta Registered, 25-year insurance-backed warranty.
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Underpinning
Structural underpinning to lower Clapham Victorian and Edwardian foundations, Temporary Works Coordinator on every job.
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Cellar Conversion
Convert existing Clapham cellars into dry, warranted rooms, minimal disruption to the house above.
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Damp Proofing
Diagnostic damp surveys across Clapham, targeted damp-proofing, no scattergun tanking.
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Sump & Pump Systems
Twin-pump, alarmed sump systems installed and commissioned across Clapham, the mechanical backbone of a dry basement.
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Basement Extension
Downward extensions in Clapham: full planning, Party Wall and design-build service.
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Light Well Installation
Engineered light wells for deep Clapham plans: glazing, drainage and edge protection included.
Learn moreWhy Clapham homeowners choose UHM.
Clapham's terraces are what basement contractors either specialise in or shy away from. Tight sites, active party walls, restricted street access, all reasons a single, accountable in-house team matters here.
One accountable team, start to finish
Recent and live projects across Old Town, The Chase, Abbeville Village and Clapham Park. Every one delivered by our own 25-strong team.
Party Wall fluent in SW4
Almost every Clapham basement is party-wall notifiable on two flanks. UHM issues notices, secures awards and liaises with adjoining-owner surveyors as part of the standard scope.
Delta Registered, 25-year warranty
Every Clapham basement is designed to BS 8102 by Delta Registered Installers and backed by a 25-year insurance-backed waterproofing warranty. £10M public liability across the whole project.
The specific problems Clapham basements face.
Clapham's Victorian brick, London Clay subsoil and terrace density produce a very consistent pattern of basement problems. Every UHM design starts by engineering those patterns out.
Old brick foundations under Victorian terraces
Most Clapham terraces sit on shallow lime-mortared Victorian brick footings | never designed for a lower-ground floor. Underpinning must be sequenced hit-and-miss with Temporary Works Coordinator sign-off, or the house above cracks.
London Clay heave & seasonal movement
SW4 sits on London Clay. Shrink-swell movement causes cracked returns and door-frame drift if excavation is rushed or waterproofing is unventilated. We sequence dig, retain and cure | never all at once.
Party walls on both flanks
Almost every Clapham mid-terrace is notifiable under the Party Wall etc. Act 1996 on two flanks. Notices, awards and schedules of condition are non-negotiable | UHM handles them all.
Restricted street access near the Common
Old Town, The Chase and the streets running north off Clapham Common demand tightly planned muck-away, skip permits and vehicle marshalling. We plan and price this before quoting.
Structured stages, no shortcuts.
Every UHM project, whether in Clapham or elsewhere in London, runs through the same disciplined sequence. You'll always know what's happening next, who's doing it and when it completes.
- 01
Free Clapham site visit
Director-led survey of your SW4 or SW11 property | measured, photographed, condition-noted.
- 02
Fixed written quote
Structural strategy, BS 8102 waterproofing spec and Lambeth Council planning notes | priced in writing.
- 03
Consents & Party Wall
Building Control, Party Wall Awards for Clapham's tight terraces | all managed by UHM.
- 04
Build on-site
Directly-employed team on your Clapham site. Neighbours protected, weekly progress reports.
- 05
Handover & warranty
Sign-off, twin-pump commissioning, 25-year structural and waterproofing warranties.
Do you serve Clapham?
Yes, Clapham SW4 is one of our most active areas with completed basement projects. We cover all SW4 postcodes and adjoining SW11, SW12 and SW9.
How fast can you reach Clapham?
Get in touch by phone or email and we will arrange a free, director-led site visit at a time that suits you.
How much does a basement cost in Clapham?
Every Clapham quote is written after a real site visit. Ground, water table, party walls and finish specification dominate cost too much for a public price list to be useful. We provide a fixed written quote after the free visit.
Do you handle Lambeth Council Building Control and Party Wall Awards in Clapham?
Yes. UHM manages Building Control inspections with Lambeth Council and Party Wall notices, awards and adjoining-owner surveyor liaison as part of the standard scope.
Can you work on Clapham terraces without disturbing neighbours?
We can never eliminate disruption for a basement dig, but we minimise it. Schedules of condition on both flanks, dust screening, vehicle-marshalled deliveries and Saturday-noise embargoes are standard UHM operating procedure on SW4 sites.
Do you cover Clapham Common flats and mansion blocks?
Yes, subject to freeholder consent. Most Clapham flat-level work is cellar conversion or damp-proofing rather than full excavation.
Serving South & West London
Book your Clapham site visit.
Free, director-led and no pressure. If Clapham's ground or your property don't suit a basement dig, we'll tell you at the visit, and explain why.
- Free site visit
- Free written quote
- 25-year warranty
- £10M insurance
- Directly-employed team