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 Underpinning · London # Basement underpinning in London,sequenced by engineers,poured by our own crews. Traditional mass-concrete and reinforced underpinning to enable basement excavation beneath your existing London home, designed with your structural engineer, executed by directly-employed labour, warranted for 25 years. Book a free site visit 07450 310772 150+ basements excavated · Temporary Works Co-ordinator on team · £10M all-risks insurance. 150+ Basements underpinned TWC Temp Works Coord. 25 yr Structural warranty £10M Insurance cover NVQ L6 Site Management Recent work ## Recent projects, delivered by UHM. View the full portfolio → Service overview ## Underpinning is the moment a basement becomes possible. Underpinning is the controlled extension of your existing foundations downwards to a new, deeper bearing level, creating the structural envelope for a basement. It is planned, sequenced, propped and cast in a strict order, because it is the discipline that keeps a London terrace standing while the ground beneath it is removed. What it is Engineer-designed underpinning of load-bearing walls in sequenced 'pins', including temporary works, propping, excavation, formwork, reinforcement, concrete pour and cure, carried out under a live building. Who it's for Homeowners undertaking a basement excavation or extension, and property owners whose existing foundations require strengthening due to subsidence, adjacent works or change of use. When it's needed Whenever a habitable basement is being excavated beneath an existing home, and in remedial situations where foundations have moved or been undermined. Why it matters Underpinning is where the structural risk of the whole basement project sits. It is not a general-builder discipline. It is the difference between a basement that lasts 100 years and one that cracks in eighteen months. Our process ## Structured stages, no shortcuts. Every UHM project runs through the same structured stages. You'll always know what's happening next, who's doing it and when it completes. - 01 ### Structural design Your engineer's underpinning drawings reviewed and converted into a buildable sequence with our Temporary Works Co-ordinator. - 02 ### Temporary works & propping Needle-and-prop scheme installed to engineered design. Party wall access agreed. Deliveries and muck-away routed. - 03 ### Sequenced pin excavation Pins excavated by hand in a strict engineer-approved sequence, never adjacent. Each pin propped, cleared and dry before pour. - 04 ### Reinforcement & concrete pour Rebar cages placed to engineer spec, formwork checked and concrete poured to the correct mix. Cured before the next pin in sequence. - 05 ### Sign-off & warranty Engineer inspection at hold points, party wall surveyor sign-off where required, structural warranty issued on completion. Technical detail ## Methods, sequences and situations we underpin for. Every underpin is site-specific. Here is the technical toolkit we use, and how each method maps to your foundations, neighbours and programme. ### Traditional mass-concrete underpinning The classic London-terrace underpinning method, hand-dug pins, mass concrete pours, sequenced to leave adjacent ground supported at all times. Reliable, cost-effective and the default choice for the majority of Victorian and Edwardian houses. - Typically 1m pins in 1-3-5 / 2-4-6 sequence - Mass concrete pours to engineer mix - Dry-pack final joint under existing foundation - Continuous inspection at hold points ### Reinforced concrete underpinning Where excavation depth exceeds mass-concrete practicalities, reinforced concrete pins carry load with steel reinforcement. Used for deeper basements and where cantilever design is required at party walls. - Structural rebar cages to engineer schedule - Deeper pins with formed faces - Cantilever detailing at party walls - Full temporary works throughout ### Retaining walls, piled solutions and hybrid designs For basements below the water table, adjacent to deep-founded neighbours or on constrained plots, piled retaining walls or hybrid designs may be specified. Specialist piling is coordinated under our direct site management, so the client sees one accountable team. - Contiguous or secant piled walls - King post retaining systems - Hybrid pinned/piled boundaries - Full CIRIA C760 compliance ### Remedial underpinning for existing homes Not every underpin is for a basement. We also carry out remedial underpinning where an existing home shows subsidence, where a wall has been undermined by adjacent works, or where a change of use requires foundation strengthening. Same discipline, same warranty. Why it's worth doing properly ## Concrete outcomes, not vague claims. ### In-house Temporary Works competence Our team holds Temporary Works Co-ordinator training as standard, the qualification the industry recognises as the underpinning safety baseline. ### Structural warranty on completion 25-year structural warranty on the completed basement, backed by UHM Ltd trading since 2009. ### NVQ Level 6 directors on every project Both directors hold NVQ Level 6 Site Management. Ghedeon attends every site every day, no absent principals. ### Programme confidence Directly-employed labour means pins are excavated and poured to the sequence we quoted, never delayed by another crew's schedule. ### Party wall discipline Method statements, surveys and access managed to the letter. Neighbours are informed, not surprised. ### Invisible when done right The best underpinning is the underpinning nobody notices. No cracks, no doors sticking, no story to tell. The real cost of the wrong contractor ## The underpinning stage is where cheap contractors reveal themselves. You can't see underpinning after it's finished. That's exactly why it's the stage cut most on price and covered up fastest. The consequences of a bad sequence don't appear during the works, they appear the first winter the ground moves. ### Foundation settlement Underpinning in the wrong sequence, or with insufficient cure time between pins, causes settlement in your walls and the party wall. Once a wall has settled, no amount of remedial work fully returns it. ### Neighbour damage and legal exposure A party wall crack caused by poorly managed underpinning becomes a party-wall claim, a legal cost and a stalled programme. The insurance disputes take longer than the build. ### Temporary works failure Propping and needling that isn't engineer-designed is the single largest cause of catastrophic underpinning failure on London sites. Temporary works is a competence, not a job for site improvisation. ### Common homeowner mistakes. - 01Choosing a contractor with no in-house Temporary Works Co-ordinator. - 02Accepting a fixed price without an engineer-designed sequence drawing. - 03Skipping party wall method statements to save time. - 04Pouring pins wider than the sequence design to 'get it done faster'. - 05Using non-structural mix concrete because it's cheaper on the day. - 06Removing propping before the engineer signs off. Frequently asked ## Real answers, before you call. Straight answers we give on almost every free site visit, cost, timeline, guarantees and what's included. 07450 310772Message us ### How much does underpinning cost in London? Underpinning is priced per project: the number depends on depth, method, party wall complexity and access. There are no fixed prices. Site visits and written quotes are free. ### How long does the underpinning stage take? Typically three to six months for a standard London terrace basement. Depth, ground conditions and party wall works can extend this. Your programme is confirmed in the written quote. ### Is my home safe to live in during underpinning? In most cases the upper floors remain occupied. Access, dust and vibration are managed by an experienced site team, and Ghedeon attends daily to check safety and progress. We'll always be honest if occupation is impractical for your specific project. ### Do you have your own Temporary Works Co-ordinator? Yes. Temporary Works Co-ordinator qualifications are held in-house, a baseline competence for any contractor doing underpinning, and one we take seriously. ### What's the warranty on the underpinning? The completed basement carries a 25-year structural warranty covering the underpinning and structural elements, backed by Underhouse Management Ltd. ### What insurance do you carry? £10,000,000 all-risks insurance covering both public and employers' liability. Documentation is available to your solicitor and party wall surveyor on request. ### Do you handle party wall matters? We support the party wall process by preparing method statements, temporary works designs, drawings and access schedules for the appointed surveyors. The surveyor role itself remains independent. ### Can you remedy underpinning done badly by someone else? Sometimes. We survey the failure, review the original engineer's design and the constructed sequence, and give you a written diagnosis. Where remedy is viable, we scope it; where it isn't, we say so. Related services ### Explore the full basement discipline - Basement Excavation - Basement Conversion - Waterproofing & Tanking - Basement Extension - Sump & Pump Systems - View all services Where we work ### Serving South London first - London - Wandsworth - Clapham - Wimbledon - Putney - Balham - Chelsea - Kensington Book your free site visit ## Ready to underpin your London home properly? The stage most contractors cut. We don't. A director will visit, review your engineer's drawings, and issue a written quote, for free. If your project needs a different structural approach, we'll tell you. - 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). Company No. 06968521. Privacy Policy·Terms & Conditions·Cookie Policy·25-year warranty · £10M insurance Call nowBook a site visit