07450 310772sales@uhmbasements.co.uk FMB  ·  Delta Registered  ·  £10M Insured  ·  25-Year Warranty About Services Areas Our Work Reviews Contact 07450 310772Book a site visit Basement specialists · Clapham SW4 # 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. Book a free site visit 07450 310772 Our own 25-strong team · Free site visit and quote · 25-year warranty. 150+ Basements excavated 17 yrs Trading since 2009 25 Directly-employed staff 25 yr Structural warranty £10M Insurance cover Local coverage ## 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. Coverage 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. Response time Call or email and a director will get back to you to arrange a free site visit at a time that suits you. Property types 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. Common needs 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. Services in Clapham ## 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. Learn more ### Basement Conversion Fully habitable Clapham lower-ground floors, kitchens, cinemas, guest suites, matched ceiling heights. Learn more ### Waterproofing & Tanking BS 8102 Type C cavity drainage across Clapham, Delta Registered, 25-year insurance-backed warranty. Learn more ### Underpinning Structural underpinning to lower Clapham Victorian and Edwardian foundations, Temporary Works Coordinator on every job. Learn more ### Cellar Conversion Convert existing Clapham cellars into dry, warranted rooms, minimal disruption to the house above. Learn more ### Damp Proofing Diagnostic damp surveys across Clapham, targeted damp-proofing, no scattergun tanking. Learn more ### Sump & Pump Systems Twin-pump, alarmed sump systems installed and commissioned across Clapham, the mechanical backbone of a dry basement. Learn more ### Basement Extension Downward extensions in Clapham: full planning, Party Wall and design-build service. Learn more ### Light Well Installation Engineered light wells for deep Clapham plans: glazing, drainage and edge protection included. Learn more Why choose UHM in Clapham ## Why 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. Location-specific challenges ## 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. Our process ## 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. Frequently asked ## Real answers for Clapham. 07450 310772Message us ### 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. Nearby areas we cover ### Serving South & West London - Balham - Wandsworth - Putney - Wimbledon - Chelsea - Kensington - Richmond upon Thames - London (all boroughs) Explore services ### Full basement discipline - Basement Excavation - Basement Conversion - Waterproofing & Tanking - Underpinning - Cellar Conversion - Damp Proofing - Sump & Pump Systems - Basement Extension - Light Well Installation Book your free site visit ## 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 teamRequest your free quote 07450 310772 Or return to the homepage · read about UHM. Underhouse Management Ltd, London's structural basement specialists. A directly-employed team of 25, delivering meticulous below-ground work across the capital's finest addresses. Established 2009. FMB·Delta Registered·Considerate Constructors ### Services - Basement Excavation - Basement Conversion - Waterproofing & Tanking - Underpinning - Cellar Conversion - Basement Extension ### Areas Served - London - Wandsworth - Clapham - Wimbledon - Putney - Balham - Chelsea - Kensington - Richmond upon Thames ### Contact - 07450 310772 - sales@uhmbasements.co.uk - Unit C220A, Trident Business Centre,89 Bickersteth Rd, London SW17 9SHBook a site visit © 2026 Underhouse Management Ltd (t/a UHM Basements). 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