--- title: "Extension Builds Liverpool — Single, Double & Wrap-Around | D2 Joinery" description: "Single and double-storey extensions across Liverpool & Merseyside. Foundations to plaster, building control coordinated, fixed quotes. 10–22 week programmes, 12-month workmanship guarantee." lang: en-GB json-ld: | [ { "@context": "https://schema.org", "@type": "LocalBusiness", "@id": "https://d2joinery.co.uk/#business", "name": "D2 Joinery, Construction & Fire Doors", "image": "/__l5e/assets-v1/fc4de6d7-7df7-4868-85a0-2f41b49310b2/d2-logo.png", "logo": "/__l5e/assets-v1/fc4de6d7-7df7-4868-85a0-2f41b49310b2/d2-logo.png", "telephone": "+447897029361", "email": "info@d2joinery.co.uk", "url": "https://d2joinery.co.uk/", "priceRange": "££", "address": { "@type": "PostalAddress", "streetAddress": "31 Radmore Rd", "addressLocality": "Liverpool", "postalCode": "L14 5NP", "addressRegion": "Merseyside", "addressCountry": "GB" }, "geo": { "@type": "GeoCoordinates", "latitude": 53.4084, "longitude": -2.9916 }, "openingHoursSpecification": [ { "@type": "OpeningHoursSpecification", "dayOfWeek": [ "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday" ], "opens": "09:00", "closes": "17:00" } ], "areaServed": [ "Liverpool", "St Helens", "Warrington", "Birkenhead", "Formby", "Wirral", "Bootle", "Southport", "Runcorn" ], "sameAs": [ "https://www.instagram.com/d2joinery", "https://www.facebook.com/profile.php?id=61577658841897", "https://maps.app.goo.gl/sgVTNFEBfsAzAEP86" ] }, { "@context": "https://schema.org", "@type": "Organization", "@id": "https://d2joinery.co.uk/#organization", "name": "D2 Joinery, Construction & Fire Doors", "url": "https://d2joinery.co.uk/", "logo": "/__l5e/assets-v1/fc4de6d7-7df7-4868-85a0-2f41b49310b2/d2-logo.png", "telephone": "+447897029361", "email": "info@d2joinery.co.uk", "sameAs": [ "https://www.instagram.com/d2joinery", "https://www.facebook.com/profile.php?id=61577658841897", "https://maps.app.goo.gl/sgVTNFEBfsAzAEP86" ], "address": { "@type": "PostalAddress", "streetAddress": "31 Radmore Rd", "addressLocality": "Liverpool", "postalCode": "L14 5NP", "addressRegion": "Merseyside", "addressCountry": "GB" } }, { "@context": "https://schema.org", "@type": "WebSite", "@id": "https://d2joinery.co.uk/#website", "url": "https://d2joinery.co.uk/", "name": "D2 Joinery, Construction & Fire Doors", "inLanguage": "en-GB", "publisher": { "@id": "https://d2joinery.co.uk/#business" } }, { "@context": "https://schema.org", "@type": "Service", "serviceType": "Extension Builds", "name": "Extension Builds in Liverpool & Merseyside", "description": "Single and double-storey extensions across Liverpool & Merseyside. Foundations to plaster, building control coordinated, fixed quotes. 10–22 week programmes, 12-month workmanship guarantee.", "url": "https://d2joinery.co.uk/services/extension-builds", "provider": { "@id": "https://d2joinery.co.uk/#business" }, "areaServed": [ { "@type": "City", "name": "Liverpool" }, { "@type": "City", "name": "St Helens" }, { "@type": "City", "name": "Warrington" }, { "@type": "City", "name": "Birkenhead" }, { "@type": "City", "name": "Formby" }, { "@type": "City", "name": "Wirral" }, { "@type": "City", "name": "Bootle" }, { "@type": "City", "name": "Southport" }, { "@type": "City", "name": "Runcorn" } ], "hasOfferCatalog": { "@type": "OfferCatalog", "name": "D2 Joinery service catalogue", "itemListElement": [ { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Fire Door Installation" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Fire Door Maintenance" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Fire Door Inspection" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Full Property Renovations" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Bespoke Joinery" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "1st & 2nd Fix Joinery" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Kitchen Installation" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Bathroom Installation" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Loft Conversions" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Extension Builds" } }, { "@type": "Offer", "itemOffered": { "@type": "Service", "name": "Decking & Outdoor Structures" } } ] } }, { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "How much does an extension cost in Liverpool?", "acceptedAnswer": { "@type": "Answer", "text": "Every extension is priced with a fixed quote after a free feasibility visit and the engineer's pack — no day rates, no call-out fee. Cost varies with footprint (single-storey, side return, wrap-around, two-storey) and specification, particularly kitchen and glazing." } }, { "@type": "Question", "name": "How long does an extension take?", "acceptedAnswer": { "@type": "Answer", "text": "Single-storey: 10–16 weeks foundation-to-plaster. Side return: 8–12 weeks. Wrap-around: 14–20 weeks. Two-storey: 16–22 weeks. Programme confirmed at quote and held to within 1–2 weeks in normal weather." } }, { "@type": "Question", "name": "Do I need planning permission?", "acceptedAnswer": { "@type": "Answer", "text": "Single-storey rear extensions up to 4m (terrace) or 6m (detached) often fall under Larger Home Extension PD with neighbour consultation. Side returns usually PD. Two-storey and wrap-arounds usually need planning. We check at feasibility — never assume." } }, { "@type": "Question", "name": "Do you handle planning and building control?", "acceptedAnswer": { "@type": "Answer", "text": "Yes — we coordinate architect, structural engineer, planning consultant and building control inspections. You sign documents; we manage the process." } }, { "@type": "Question", "name": "Can I live in the house during the extension?", "acceptedAnswer": { "@type": "Answer", "text": "Yes, on most single-storey rear extensions. The kitchen will be temporarily relocated to the dining room or utility for 4–6 weeks during the kitchen fit. Two-storey extensions are more disruptive — many clients move out for 4–6 weeks." } }, { "@type": "Question", "name": "What's the value uplift?", "acceptedAnswer": { "@type": "Answer", "text": "A well-designed extension often delivers value uplift greater than the build cost — but only if the design and finish are right. Your estate agent can give you a property-specific figure for the local market." } }, { "@type": "Question", "name": "Do you work with architects or design in-house?", "acceptedAnswer": { "@type": "Answer", "text": "We frequently take over from architects at tender stage and deliver on their drawings. We also have trusted local architects we can recommend if you don't yet have one." } }, { "@type": "Question", "name": "What guarantee do I get?", "acceptedAnswer": { "@type": "Answer", "text": "12-month workmanship guarantee on the whole build. Optional 10-year structural warranty (LABC or CRL) for larger schemes — gives mortgage lenders the comfort they want." } } ] }, { "@context": "https://schema.org", "@type": "BreadcrumbList", "itemListElement": [ { "@type": "ListItem", "position": 1, "name": "Home", "item": "https://d2joinery.co.uk/" }, { "@type": "ListItem", "position": 2, "name": "Services", "item": "https://d2joinery.co.uk/services" }, { "@type": "ListItem", "position": 3, "name": "Extension Builds", "item": "https://d2joinery.co.uk/services/extension-builds" } ] } ] --- 31 Radmore Rd, Liverpool L14 5NP Open daily, 8am–10pm [info@d2joinery.co.uk](mailto:info@d2joinery.co.uk)[07897 029361](tel:+447897029361) [![D2 Joinery, Construction & Fire Doors — Liverpool fire door & joinery contractor](/__l5e/assets-v1/fc4de6d7-7df7-4868-85a0-2f41b49310b2/d2-logo.png)](/) [About](/about) Fire Door Services [ Fire Door Installation Certified FD30 / FD60 fire door supply, installation and remedial works with full compliance pack. ](/services/fire-doors)[ Fire Door Maintenance qualified planned and reactive fire door maintenance — seals, closers, ironmongery, sign-off. ](/services/fire-door-maintenance)[ Fire Door Inspection Annual and quarterly fire door inspections under the Fire Safety (England) Regulations 2022, with photo logs. ](/services/fire-door-inspection)[View all D2 services →](/services) Other Services [ Full Property Renovations ](/services/full-property-renovations)[ Bespoke Joinery ](/services/bespoke-joinery)[ 1st & 2nd Fix Joinery ](/services/1st-2nd-fix-joinery)[ Kitchen Installation ](/services/kitchen-installation)[ Bathroom Installation ](/services/bathroom-installation)[ Loft Conversions ](/services/loft-conversions)[ Extension Builds ](/services/extension-builds)[ Decking & Outdoor Structures ](/services/decking-outdoor-structures)[View all joinery & construction services →](/services) Areas [Liverpool](/areas/liverpool)[St Helens](/areas/st-helens)[Warrington](/areas/warrington)[Birkenhead](/areas/birkenhead)[Formby](/areas/formby)[Wirral](/areas/wirral)[Bootle](/areas/bootle)[Southport](/areas/southport)[Runcorn](/areas/runcorn)[View all Merseyside coverage areas →](/areas) [Our Work](/our-work)[Contact](/contact) [07897 029361 ](tel:+447897029361)[Request Estimate](/contact) [Home](/)/ [Services](/services)/ Extension Builds Extension Builds · Liverpool & Merseyside # Single & Double Storey Extensions Designed, Built & Signed Off Across Liverpool & Merseyside Rear, side-return and wrap-around extensions delivered as one contract — foundations to plaster, building control coordinated, planning support included. Fixed price, fixed programme. [Request a Free Estimate](/contact) [07897 029361](tel:+447897029361) Foundations to plaster typically 10–16 weeks on a single-storey rear. 16 yrs joinery experience Certified Installer Fully insured (£5m PL) Companies House #15212735 Surveys booked in 5–7 days Service Overview ## Extension Builds — what's actually involved ### What it is An extension build is the construction of new habitable floor area attached to an existing property — single-storey rear or side, two-storey rear, wrap-around L-shape, or front porches. The job runs from groundworks (foundations, oversite, drains) through superstructure (masonry or timber frame), roof, windows and doors, services, plaster, joinery, kitchen and decoration. We act as principal contractor on the whole job. ### Who it's for Families needing more living space, downsizers upgrading the home they intend to retire in, landlords adding bedrooms to lift HMO income, and any homeowner whose ground floor doesn't work — the classic Victorian narrow kitchen, the dated 1960s lean-to, the disconnected dining room. Extensions are the most common way to add the space modern living needs without leaving the area. ### When you need it When the existing footprint is restricting how the family lives — kitchen too small for a table, no downstairs WC, no utility, no real connection to the garden. Also when the existing structure (old single-skin lean-to, leaking flat roof, condensing wet kitchen) is failing and replacement makes more sense than repair. ### Why professional matters Extensions are the most regulated and the most expensive home improvement most clients ever undertake. Done badly — wrong foundations for the soil, undersized steels, leaky roof junctions, condensation traps in poorly-insulated walls — they devalue the property and create 20-year problems. Done properly, they add 20–30% to the value and transform how the house lives. What happens if it's ignored ## The cost of leaving it — or getting it wrong ### Cheap quotes with wrong foundations Soil type and tree proximity dictate foundation depth and design (NHBC chapter 4.2). A 'standard' trench-fill quote without a site investigation is a future subsidence claim. We get the soil right or we don't quote. ### Roof junctions that always leak Where a new flat or pitched roof meets the existing house, the lead flashing detail is critical. Done with mortar fillets or skimped lead, it leaks within 2–3 winters. ### Cold bridges and condensation traps Modern thermal regs (Approved Doc L) demand continuous insulation around openings, in cavities and at floor/wall junctions. Skipping the insulation between blockwork and cill creates a cold bridge that grows mould. ### Permitted Development overruns and planning enforcement Many extensions go ahead under Permitted Development — but PD has strict limits (depth, height, ridge, materials). Exceeding them is enforceable. We check PD against your specific deeds and conservation status before designs are signed. Our Process ## A defined system — so you know exactly what happens next 1. Step 1 ### Feasibility & planning support Site visit, feasibility on permitted development or planning, indicative cost band. We coordinate architect, structural engineer and planning consultant — or work to your existing drawings. 2. Step 2 ### Detailed quote & programme Once drawings and engineer's pack are complete, we issue a fixed price broken down by package (groundworks, superstructure, roof, windows, services, finishes) with a week-by-week programme. 3. Step 3 ### Groundworks & superstructure Foundations dug, inspected by building control, concreted. Oversite, drains, DPC. Masonry or timber-frame superstructure with cavity insulation. Roof on, building watertight. 4. Step 4 ### First fix, plaster & second fix Electrics, plumbing and heating first-fixed. Insulation and plasterboard. Plastered. Kitchen or other internal works second-fixed. Windows and doors fitted (FENSA-registered partner). 5. Step 5 ### Building control sign-off & decoration Final building control visit, completion certificate and FENSA cert. Decoration, snag, deep clean. 12-month workmanship guarantee, structural warranty available on larger projects. The benefits ## What you get when D2 delivers the job ### One contractor, one contract Architect, engineer, contractor and trades coordinated by us. You don't manage subcontractors. ### Fully compliant build Building control sign-off and FENSA certificates — the pack a buyer's solicitor wants to see. ### Significant value uplift A typical single-storey rear extension on a Liverpool 3-bed semi delivers a meaningful uplift in property value, often more than the build cost. ### Fixed quote, no surprises Fixed price tied to the engineer's drawings. Variations only at your written approval — never sprung on you. ### Designed for how the family lives Sightlines from kitchen to garden, sockets where appliances actually go, lighting layered for cooking and entertaining. We design with you. ### 12-month workmanship + structural warranty 12 months on our workmanship. Optional 10-year structural warranty (LABC or CRL) available on larger schemes. In Detail ## Materials, methods and the situations they suit Extensions vary by footprint, structure and complexity. Below are the four most-built extension types in Liverpool and Merseyside, with the technical detail that makes the difference. ### Single-storey rear extension Typically 3–6m deep across the rear of a Victorian terrace or 1930s semi. Cavity-wall masonry or timber-frame superstructure on trench-fill or strip foundations. Flat roof in EPDM or GRP, or pitched roof with rooflights. Bifold or sliding doors to garden. The most common extension type — adds open-plan kitchen-diner-living space. 10–16 weeks. ### Side return infill (Victorian terraces) Filling in the narrow side passage on a Victorian terrace — turns a 2.4m kitchen into a 4.5m+ kitchen-diner. Roof typically a glazed lantern or skylight for daylight in the new space. Party-wall agreements required for both neighbours. 8–12 weeks. ### Wrap-around (rear + side return) Combining a rear and side return into an L-shape. Creates a generous open-plan ground floor with three external walls of glazing potential. Steel beams over the original kitchen wall removal. Usually requires planning permission (exceeds PD limits in most cases). 14–20 weeks. ### Two-storey rear extension Doubles the value of a rear extension — kitchen-diner downstairs and bedroom or larger bathroom upstairs. Foundations need to be deeper and wider; party-wall awards needed for terraces and semis; planning permission required in most cases. Highest-value extension type per square metre. 16–22 weeks. ### Foundations, steels and structural design Foundation depth driven by soil type, tree roots and existing structures — typically 1m–2.5m trench fill for Liverpool clay soils, deeper near mature trees. Steel beams sized by structural engineer to the loads above, with bearing details onto padstones. Wind-post connections at new-to-old junctions to prevent cracking. We get the engineer in at quote stage so the price reflects what the build actually needs. Frequently Asked ## Extension Builds — your questions answered How much does an extension cost in Liverpool? Every extension is priced with a fixed quote after a free feasibility visit and the engineer's pack — no day rates, no call-out fee. Cost varies with footprint (single-storey, side return, wrap-around, two-storey) and specification, particularly kitchen and glazing. How long does an extension take? Do I need planning permission? Do you handle planning and building control? Can I live in the house during the extension? What's the value uplift? Do you work with architects or design in-house? What guarantee do I get? Related Services ## Often paired with extension builds [ ### Loft Conversions A loft conversion turns unused roof space into a habitable room — typically a bedroom, en-suite, home office or studio. Explore Loft Conversions ](/services/loft-conversions)[ ### Full Property Renovations A full property renovation is a coordinated programme of works — strip-out, structural alterations, services first fix, plastering, joinery, kitchens, bathrooms, flooring, decoration and snagging — delivered to a fixed scope, a fixed price and a defined timeline. Explore Full Property Renovations ](/services/full-property-renovations)[ ### Kitchen Installation Kitchen installation is the full job: strip-out of the existing kitchen, services first-fix (plumbing, electrics, gas), plastering, flooring, supply and fit of the new units, worktops, sink and tap, appliances, splashback, decoration and snag. Explore Kitchen Installation ](/services/kitchen-installation) See all [D2 services](/services) or [return to the homepage](/). ![D2 Joinery certified fire doors and bespoke joinery services across Liverpool and Merseyside](/assets/cta-services-Ca9m4pP-.jpg) ## Get a feasibility visit and indicative quote. Free across Liverpool & Merseyside. Honest answer on what's achievable, with a realistic budget — within 7 days. [Request a Free Estimate](/contact) [07897 029361](tel:+447897029361) Free survey & fixed quote · No call-out fee · Reply within one working day · £5m public liability ![D2 Joinery, Construction & Fire Doors — Liverpool fire door & joinery contractor](/__l5e/assets-v1/fc4de6d7-7df7-4868-85a0-2f41b49310b2/d2-logo.png) Fire door compliance specialists and bespoke joiners serving Liverpool and Merseyside — within an hour's drive of L14. Decking, pergolas, garden rooms and single- and double-storey extensions too. £5 million public liability cover. Free surveys and fixed-quote estimates, with no call-out fee. [](https://www.instagram.com/d2joinery)[](https://www.facebook.com/profile.php?id=61577658841897) ### Services - [Fire Door Installation](/services/fire-doors) - [Fire Door Maintenance](/services/fire-door-maintenance) - [Fire Door Inspection](/services/fire-door-inspection) - [Full Property Renovations](/services/full-property-renovations) - [Bespoke Joinery](/services/bespoke-joinery) - [1st & 2nd Fix Joinery](/services/1st-2nd-fix-joinery) ### Areas - [Liverpool](/areas/liverpool) - [St Helens](/areas/st-helens) - [Warrington](/areas/warrington) - [Birkenhead](/areas/birkenhead) - [Formby](/areas/formby) - [Wirral](/areas/wirral) ### Contact - [07897 029361](tel:+447897029361) - [07859 992855](tel:+447859992855) - [info@d2joinery.co.uk](mailto:info@d2joinery.co.uk) - 31 Radmore Rd Liverpool L14 5NP - Open daily, 8am–10pm © 2026 D2 Joinery, Construction & Fire Doors. All rights reserved. Companies House #15212735. 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