--- title: "House Extensions London, Side, Rear & Wrap-Around Builders | Refurb Squad Ltd" description: "Side, rear and wrap-around house extensions across North & West London. In-house architects, structural sign-off and building control handled. Fixed-price quote, 12-month guarantee, £1M insured." lang: en-GB json-ld: | [ { "@context": "https://schema.org", "@type": "Organization", "name": "Refurb Squad Ltd", "legalName": "Refurb Squad Ltd", "url": "https://refurbsquad.co.uk/", "logo": "/__l5e/assets-v1/f9b26d00-6a9f-41e2-bfd0-ed2944fb2706/refurb-squad-favicon.png", "image": "/__l5e/assets-v1/f9b26d00-6a9f-41e2-bfd0-ed2944fb2706/refurb-squad-favicon.png", "telephone": "+44 7460 046234", "email": "office@refurbsquad.co.uk", "founder": { "@type": "Person", "name": "Jay Reid" }, "foundingDate": "2014", "address": { "@type": "PostalAddress", "streetAddress": "124 City Road", "addressLocality": "London", "postalCode": "EC1V 2NX", "addressCountry": "GB" } }, { "@context": "https://schema.org", "@type": "WebSite", "name": "Refurb Squad Ltd", "url": "https://refurbsquad.co.uk/", "publisher": { "@type": "Organization", "name": "Refurb Squad Ltd" }, "inLanguage": "en-GB" }, { "@context": "https://schema.org", "@type": "LocalBusiness", "name": "Refurb Squad Ltd", "image": "/__l5e/assets-v1/f9b26d00-6a9f-41e2-bfd0-ed2944fb2706/refurb-squad-favicon.png", "@id": "https://refurbsquad.co.uk", "telephone": "+44 7460 046234", "email": "office@refurbsquad.co.uk", "address": { "@type": "PostalAddress", "streetAddress": "124 City Road", "addressLocality": "London", "postalCode": "EC1V 2NX", "addressCountry": "GB" }, "openingHoursSpecification": [ { "@type": "OpeningHoursSpecification", "dayOfWeek": [ "Monday", "Tuesday", "Wednesday", "Thursday", "Friday" ], "opens": "08:00", "closes": "16:00" }, { "@type": "OpeningHoursSpecification", "dayOfWeek": "Saturday", "opens": "09:00", "closes": "13:00" } ], "areaServed": [ "St John's Wood", "Paddington", "Kensington", "Bayswater", "Regents Park", "Hampstead", "Hammersmith", "Chiswick", "Ealing Broadway" ], "priceRange": "££££", "founder": { "@type": "Person", "name": "Jay Reid" }, "aggregateRating": { "@type": "AggregateRating", "ratingValue": "5.0", "reviewCount": "3" } }, { "@context": "https://schema.org", "@type": "Service", "name": "House Extensions", "serviceType": "House Extensions", "areaServed": [ "St John's Wood", "Paddington", "Kensington", "Bayswater", "Regents Park", "Hampstead", "Hammersmith", "Chiswick", "Ealing Broadway" ], "provider": { "@type": "LocalBusiness", "name": "Refurb Squad Ltd", "telephone": "+44 7460 046234", "email": "office@refurbsquad.co.uk", "address": { "@type": "PostalAddress", "streetAddress": "124 City Road", "addressLocality": "London", "postalCode": "EC1V 2NX", "addressCountry": "GB" } }, "description": "Side, rear and wrap-around house extensions across North & West London. In-house architects, structural sign-off and building control handled. Fixed-price quote, 12-month guarantee, £1M insured." }, { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "How much does a house extension cost in London?", "acceptedAnswer": { "@type": "Answer", "text": "Every extension is quoted on a fixed-price basis after a feasibility survey. Ground conditions, glazing spec, roof form and internal finish drive the number, so we never quote from postcodes alone. You'll have an itemised written quote back inside 2-3 weeks." } }, { "@type": "Question", "name": "How long does a rear extension take?", "acceptedAnswer": { "@type": "Answer", "text": "A single-storey rear extension typically runs 12-16 weeks on site once ground works start. Design, planning and Party Wall usually add 8-12 weeks before that. The full programme is agreed in writing before we mobilise." } }, { "@type": "Question", "name": "Do I need planning permission?", "acceptedAnswer": { "@type": "Answer", "text": "Many rear and side-return extensions in London fall under permitted development, but PD rights are restricted in conservation areas and on flats. We check this at the feasibility stage and confirm whether a full planning application, PD prior-approval or a Lawful Development Certificate is needed." } }, { "@type": "Question", "name": "What is a Party Wall Award and do I need one?", "acceptedAnswer": { "@type": "Answer", "text": "If your extension abuts, cuts into or excavates near a shared wall, the Party Wall etc. Act 1996 requires you to serve notice on neighbours. We arrange the notices and, where a surveyor is appointed, coordinate the Award as part of the job." } }, { "@type": "Question", "name": "Do you handle architects and structural engineers?", "acceptedAnswer": { "@type": "Answer", "text": "Yes. Architectural drawings and structural engineer sign-off are handled in-house through our design partners. You deal with one contact for the whole project." } }, { "@type": "Question", "name": "What guarantee do you offer on extensions?", "acceptedAnswer": { "@type": "Answer", "text": "Every extension carries our 12-month workmanship guarantee in writing. Manufacturer warranties on glazing, roofing membranes and boilers sit on top of that. For mortgage or resale purposes we can also arrange a structural warranty on request." } }, { "@type": "Question", "name": "Can I stay in the house during the build?", "acceptedAnswer": { "@type": "Answer", "text": "Yes, in most cases. We phase the works so the existing kitchen or bathroom is only out of use for the second-fix stage, and we agree noise / access hours with you up front." } }, { "@type": "Question", "name": "Which areas of London do you build in?", "acceptedAnswer": { "@type": "Answer", "text": "We build throughout North and West London, including St John's Wood, Paddington, Kensington, Bayswater, Regents Park, Hampstead, Hammersmith, Chiswick and Ealing Broadway." } }, { "@type": "Question", "name": "Will the extension add value to my property?", "acceptedAnswer": { "@type": "Answer", "text": "In prime North and West London, a well-detailed extension is one of the highest-return capital works you can do, typically returning more than its build cost at resale. Specific uplift is best confirmed with a local estate agent against comparable sold prices on your street." } } ] }, { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "/" }, { "@type": "ListItem", "position": 2, "name": "Services", "item": "/services" }, { "@type": "ListItem", "position": 3, "name": "House Extensions", "item": "https://refurbsquad.co.uk/services/house-extensions" } ] } ] --- 124 City Road, London EC1V 2NX Mon-Fri 8:00-16:00 · Sat 9:00-13:00 [office@refurbsquad.co.uk](mailto:office@refurbsquad.co.uk) [07460 046234](tel:07460046234) [![Refurb Squad Ltd](/__l5e/assets-v1/1a8c6a75-dde4-4cad-91d2-4cb96e5a1b88/logo.png)](/) [Home](/)[About](/about) [Services](/services) [Service Area](/areas) [Our Work](/our-work)[Reviews](/reviews)[Contact](/contact) [07460 046234](tel:07460046234)[Request Estimate](/contact) ![Blockwork under construction on a single-storey London rear house extension by Refurb Squad](/__l5e/assets-v1/74a29370-5539-4ed9-99b9-7f2e66113b7f/House_Extensions.jpeg) [Home](/)/ [Services](/services)/ House Extensions House Extensions · London # House extensions in London, designed, built and signed off. Side-returns, rear and wrap-around extensions delivered watertight, insulated and finished to spec, with the architect, structural engineer and building control coordinated inside one fixed-price contract. Typical single-storey rear extension: 12-16 weeks on site. [Request a free estimate](/contact) [07460 046234](tel:07460046234) 5.0★ on Google · Constructionline Gold · Written quote back in the same week. 15 yrs On the tools £1M Public liability 5.0★ Google rated 12 mo Workmanship guarantee Same wk Written quote Service overview ## Extension design and build under one contract ### What it is A full house extension covers feasibility, architectural design, structural engineering, planning or permitted-development submission, building regulations, ground works, structure, roof, glazing, first fix, second fix, and internal finishing including kitchens and bathrooms where required. We manage the whole scope in-house. ### Who it's for Owners of London terraces, semis and townhouses who want to unlock a bigger kitchen-diner, an additional bedroom, a home office, or open-plan family living without moving house. ### When you need it The typical trigger is a growing family, a home-working set-up that no longer fits, or a purchase where the ground-floor footprint is holding the property back. Extensions are also the highest-return capital works you can do on a London property. ### Why professional matters An extension isn't a bigger version of a bathroom fit, it's a structural project with planning, building-control, party-wall and insurance-backed warranty implications. Getting the design and structural work right up front is what separates an extension that adds £250k of value from one that leaks in winter three. The cost of getting it wrong ## Why cheap extensions cost more in the long run Extensions fail when the sequence is wrong or the design has been priced without properly checking the ground, the structure or the neighbouring party wall. Here's what that costs. If ignored - Party-wall disputes stall the build Skip a proper Party Wall Award and a neighbour can freeze the job mid-dig. Delay costs on labour and hire are ruinous once you're past ground works. - Undersized foundations London clay is unforgiving. Cheap foundations sized without a soil review crack corners of new brickwork inside 24 months and can't be retrofitted cheaply. - Cold-bridge and condensation failures Poorly detailed junctions between old and new roofs produce cold bridges, black mould in bedroom ceilings and heat-loss you'll be paying for every winter. - Building control sign-off refused Work built off-spec doesn't pass building control. Uncertified work is a red flag on every future sale enquiry. Common mistakes - Starting on price alone The cheapest tender almost always excludes something, usually structural steels, waste connections or an insured warranty. What arrives as an 'extra' 3 months in isn't an extra, it's an omission. - No single point of accountability When architect, structural engineer and builder are three separate companies, buck-passing is guaranteed. One design-and-build contract fixes it. - Under-specifying glazing Skimping on glazing g-values leaves an extension that overheats in July and haemorrhages heat in January. The uplift to proper thermal glazing is small; the running cost of getting it wrong is enormous. How it works ## A step-by-step system, not a guess. 1. 01 Step 1 ### Feasibility & free survey Site visit, measure-up, review of what's achievable under permitted development or planning. Local surveys are free. 2. 02 Step 2 ### Design & fixed quote Architectural drawings, structural sign-off, and a detailed fixed-price quote back with you, normally inside 2-3 weeks for extensions. 3. 03 Step 3 ### Planning & Party Wall Planning or PD application submitted, Party Wall Notices served, building control appointed. We handle the paperwork end-to-end. 4. 04 Step 4 ### Build phase Ground works, structure, roof, glazing, first and second fix, weekly written progress updates from the founder himself. 5. 05 Step 5 ### Sign-off & guarantee Building control completion certificate, snag-free handover, and a 12-month workmanship guarantee in writing. What you actually get ## Concrete outcomes, not adjectives. ### One design-and-build contract Architect, structural engineer, builder, one point of contact, one accountable price. ### Correct foundations, once Foundations designed against actual soil conditions, not a guess. No cracked corners two winters in. ### Thermally-detailed junctions Old-to-new roof and wall junctions detailed against condensation risk. No mould, no cold bridges. ### Building control handled Planning, PD, Party Wall Notices, building regs and completion certificate, arranged as part of the job. ### PRINCE2 project management Programme managed against milestones with weekly written client updates. ### 12-month workmanship guarantee Written guarantee on top of any manufacturer warranties on windows, roofing and glazing. Materials & methods ## Extension types, materials & structural methods Every London extension is different. Terrace footprints, boundary constraints, and planning history all shape what's possible. Here's the range we deliver. ### Materials we work with - Traditional cavity-wall brick and block with insulated cavities - Timber-frame and SIPS panel construction for faster shell erection - Steel-frame structural openings for open-plan interiors - Warm-roof flat roofs with EPDM, single-ply or GRP finishes - Aluminium sliding, bi-fold and lantern rooflight glazing - Solid-timber and engineered flooring, cast-in-situ concrete floors, polished screed - Underfloor heating manifolds coordinated with new boiler capacity ### Methods & standards - Trial holes and (where needed) engineer-designed foundations against soil conditions - Steel schedule prepared by an independent structural engineer - Party Wall Awards where the extension abuts or approaches a shared wall - Building control inspections at foundation, DPC, superstructure and completion - Thermally detailed junctions to eliminate cold bridging at old-to-new interfaces ### Variations of this service Single-storey rear extension The most common London extension, 3-6m deep off the back of the house, usually forming an open-plan kitchen-diner. Side-return infill Filling in the side alley on Victorian and Edwardian terraces to widen the kitchen. Requires party-wall handling on both sides. Wrap-around extension Combining rear and side-return in a single L-shape to maximise ground-floor space. Double-storey rear extension Adding a bedroom or bathroom above a new kitchen extension. Requires more careful structural work into existing floor levels. Garden-room / annexe builds Detached garden studios and annexes for home working, gyms or guest accommodation. ### Property types & settings We build extensions on Victorian and Edwardian terraces, semis and detached houses across North and West London. Commercial extensions, small retail and hospitality, are handled under our commercial fit-out service. ### Areas we cover - [St John's Wood](/areas/st-johns-wood) - [Paddington](/areas/paddington) - [Kensington](/areas/kensington) - [Bayswater](/areas/bayswater) - [Regents Park](/areas/regents-park) - [Hampstead](/areas/hampstead) - [Hammersmith](/areas/hammersmith) - [Chiswick](/areas/chiswick) - [Ealing Broadway](/areas/ealing-broadway) Answers ## Straight answers, before you call. Still not sure? Call Jay directly on [07460 046234](tel:07460046234). How much does a house extension cost in London? Every extension is quoted on a fixed-price basis after a feasibility survey. Ground conditions, glazing spec, roof form and internal finish drive the number, so we never quote from postcodes alone. You'll have an itemised written quote back inside 2-3 weeks. How long does a rear extension take? A single-storey rear extension typically runs 12-16 weeks on site once ground works start. Design, planning and Party Wall usually add 8-12 weeks before that. The full programme is agreed in writing before we mobilise. Do I need planning permission? Many rear and side-return extensions in London fall under permitted development, but PD rights are restricted in conservation areas and on flats. We check this at the feasibility stage and confirm whether a full planning application, PD prior-approval or a Lawful Development Certificate is needed. What is a Party Wall Award and do I need one? If your extension abuts, cuts into or excavates near a shared wall, the Party Wall etc. Act 1996 requires you to serve notice on neighbours. We arrange the notices and, where a surveyor is appointed, coordinate the Award as part of the job. Do you handle architects and structural engineers? Yes. Architectural drawings and structural engineer sign-off are handled in-house through our design partners. You deal with one contact for the whole project. What guarantee do you offer on extensions? Every extension carries our 12-month workmanship guarantee in writing. Manufacturer warranties on glazing, roofing membranes and boilers sit on top of that. For mortgage or resale purposes we can also arrange a structural warranty on request. Can I stay in the house during the build? Yes, in most cases. We phase the works so the existing kitchen or bathroom is only out of use for the second-fix stage, and we agree noise / access hours with you up front. Which areas of London do you build in? We build throughout North and West London, including St John's Wood, Paddington, Kensington, Bayswater, Regents Park, Hampstead, Hammersmith, Chiswick and Ealing Broadway. Will the extension add value to my property? In prime North and West London, a well-detailed extension is one of the highest-return capital works you can do, typically returning more than its build cost at resale. Specific uplift is best confirmed with a local estate agent against comparable sold prices on your street. ![London roofing preparation with battens and breathable membrane used as a refurbishment call-to-action background](/__l5e/assets-v1/3d2e06f4-c5bb-4116-a2a3-2220a1df9443/Roofing_2.jpeg) Book your free survey ## Ready to price your house extensions the honest way? One site visit. One fixed-price written quote back the same week. No pressure, no hard sell, just the number and the plan to deliver it. [Request your free estimate](/contact) [07460 046234](tel:07460046234) - Free local survey - Written quote the same week - Fixed-price, staged payments - 12-month workmanship guarantee Related services ## Other work we deliver [View all services](/services) [ Service ### Loft Conversions Learn more ](/services/loft-conversions)[ Service ### Full Renovations Learn more ](/services/renovations)[ Service ### Kitchen Installation Learn more ](/services/kitchen-installation) ![Refurb Squad Ltd](/__l5e/assets-v1/1a8c6a75-dde4-4cad-91d2-4cb96e5a1b88/logo.png) Premium bathroom, kitchen and full-property renovations across North & West London. Founded by Jay Reid, 15 years on the tools, PRINCE2 project management, Gas Safe registered. [07460 046234](tel:07460046234) [office@refurbsquad.co.uk](mailto:office@refurbsquad.co.uk) 124 City Road, London EC1V 2NX [5.0★ on Google, read our reviews](/reviews)[Leave us a Google review](https://search.google.com/local/writereview?placeid=ChIJm3KT4cJpXwQRjsaNr8_GV4w) [](https://www.instagram.com/refurbsquad)[](https://www.facebook.com/share/197CgwmVVy/?mibextid=wwXIfr) Services - [Bathroom Installation](/services/bathroom-installation) - [Kitchen Installation](/services/kitchen-installation) - [House Extensions](/services/house-extensions) - [Loft Conversions](/services/loft-conversions) - [Full Renovations](/services/renovations) - [Commercial Fit-Out](/services/commercial) Service Areas - [St John's Wood](/areas/st-johns-wood) - [Paddington](/areas/paddington) - [Kensington](/areas/kensington) - [Bayswater](/areas/bayswater) - [Regents Park](/areas/regents-park) - [Hampstead](/areas/hampstead) - [Hammersmith](/areas/hammersmith) - [Chiswick](/areas/chiswick) - [Ealing Broadway](/areas/ealing-broadway) Hours - Mon-Fri · 8:00-16:00 - Saturday · 9:00-13:00 - Sunday · Closed - 24 Hrs on the Line Accredited - Gas Safe Registered - Constructionline Gold - CHAS Accredited - £1M Public Liability © 2026 Refurb Squad Ltd. 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