--- title: "House Extensions in Barnsley & Yorkshire | Johnsons" url: https://johnsonsbuildingservicesyorkshire.co.uk/services/house-extensions description: "Single & double-storey house extensions in Barnsley and across Yorkshire. Family-run builders, 20+ years' experience, fixed written quote within 48 hours." lang: en-GB --- Image: Rear of a Yorkshire family home with newly built single-storey extension and bifold doors, completed by Johnsons Building Services (https://johnsonsbuildingservicesyorkshire.co.uk/assets/project-29-CWoz1Qc-.jpeg) House Extensions # House Extensions in Barnsley Built by One Trusted Team — Designed, Managed and Finished by Us Add the room your family actually needs without the chaos of multiple contractors. Fully project-managed extensions delivered on a fixed written price, with a clear weekly programme from groundworks to final paint. Request a Free Quote: https://johnsonsbuildingservicesyorkshire.co.uk/contact 07427 916462: +447427916462 20+ years building across Yorkshire · Fixed written quote in 48 hours - 20+ Years building - 150+ Extensions completed - 10 yr Workmanship guarantee - £2m Public liability cover - 48 hr Quote turnaround Overview ## What a properly built extension actually gives you A house extension is the most cost-effective way to get the layout you want without the upheaval of moving. Done correctly, it delivers more daylight, a better-flowing ground floor and a measurable uplift in your property's value — typically 10–20% in Barnsley, Sheffield and the surrounding Yorkshire market. We handle the full build: foundations, structural steels, brick and blockwork, roof, windows and doors, first and second fix, plastering and decoration. You deal with one point of contact — the same person on day one is on site at handover. ### Who it's for Growing families, owners of pre-1990 homes with cramped kitchens, and anyone wanting an open-plan kitchen-diner, utility, downstairs WC, master suite or home office. ### When you need it When moving costs (stamp duty, fees, removals) would exceed £25–40k, or when the location is right but the layout is wrong. ### Why use a professional Extensions involve Building Regulations, Party Wall Act notices, structural calculations, drainage diversions and SAP-compliant insulation. Mistakes here are expensive to undo and uninsurable if uncertified. Why It Matters ## What goes wrong when an extension is built badly We are regularly called in to fix work started by general handymen or one-man-bands. The pattern is depressingly consistent. RISK 01 ### Foundations dug too shallow Causes settlement cracks within 18 months. Remediation usually means underpinning at £1,200–£1,800 per linear metre. RISK 02 ### Steel beams undersized or unrestrained Ceilings sag, doors stick, plaster cracks reappear no matter how often they are filled. A structural engineer's calculation is mandatory — not optional. RISK 03 ### Cold bridging at the junction Cheap detailing where the new wall meets the old causes condensation, black mould and a permanently cold corner. Fails Building Regs Part L. RISK 04 ### No Building Control sign-off When you sell, the buyer's solicitor will ask for the completion certificate. Without it the sale stalls and indemnity insurance only papers over the crack. RISK 05 ### Open programme, open wallet Builds without a written programme drift for months. Your kitchen stays in the garage, your patience runs out, and the 'cheap' price ends up the dearest. Our Process ## A clear five-step system, from first call to final sign-off 1. 01 ### Site visit & brief We measure up, listen to how you actually live, and walk you through realistic options against your budget. 2. 02 ### Fixed written quote Itemised price within 48 hours. No vague allowances — every door, socket and tile is specified. 3. 03 ### Drawings & approvals We coordinate the architect, structural engineer and Building Control submissions on your behalf. 4. 04 ### Programmed build Foundations, structure, watertight shell, first fix, plaster, second fix and decoration — to a weekly schedule you can see. 5. 05 ### Sign-off & guarantee Building Control completion certificate handed over with a 10-year written workmanship guarantee. Benefits ## What you actually get when we run the job ### Fixed price, not 'from' You sign off the cost before we lift a shovel. Variations are quoted in writing and approved before any work happens. ### One trusted crew Our own bricklayers, joiners and plasterers — no rotating subcontractors who've never met you. ### Programmed weekly You always know what is happening this week and next. Your home is not a mystery. ### Building Regs sign-off Full certification handed over on completion — protecting your resale value forever. ### Tidy site every Friday Skips emptied, materials covered, your driveway swept. We work in your home, not on a building site. ### 10-year guarantee Written workmanship cover plus manufacturer warranties on windows, roofing and boilers. In Detail ## Extension types and detailing we deliver across Yorkshire Every street in Barnsley, Sheffield, Wakefield and Leeds has its own stock — from interwar semis with rear returns to 1970s detached houses with attached garages. The right extension type depends on the property, the plot and the planning context. ### Single-storey rear extensions Typically 3–6m deep, opening onto the garden via bi-fold or sliding aluminium doors. Most are Permitted Development under the Larger Home Extension prior approval route, removing the need for full planning permission. ### Side-return infills Common on Victorian and Edwardian terraces in Sheffield and Leeds. Fills the awkward narrow strip beside the kitchen, instantly turning a galley layout into a wide kitchen-diner with rooflights. ### Wrap-around (L-shaped) extensions Combines a rear and side return. The largest single uplift in usable space — perfect for an open-plan kitchen, dining and snug zone. ### Double-storey extensions Add an extra bedroom and en-suite above a kitchen-diner. Cost per square metre is lower than single-storey because the foundations and roof serve two floors. ### Over-structure extensions Building above an existing single-storey kitchen or garage. Requires a full structural survey to confirm foundations and walls can carry the new load. ### Materials we work with Reclaimed and new brick to match Yorkshire stock, natural stone where conservation requires, render systems (silicone and mineral), zinc and standing-seam roofs, oak frames, and aluminium glazing from Origin, Smart Systems and Schüco. ### Glazing strategy Bi-folds for full opening, sliders for cleaner sightlines, fixed picture windows for view-framing, and rooflights (Velux or flat-glass) to bring daylight deep into the plan. ### Heating and insulation Underfloor heating on a 75mm screed over 100mm PIR is now standard for new extensions. Wall U-values built to 0.18 W/m²K, roof to 0.13 — well inside current Building Regs Part L. FAQ ## Straight answers to the questions we hear most ### How much does a house extension cost in Barnsley? ### How long does the build take? ### Do I need planning permission? ### Will I have to move out during the build? ### Do you handle architect's drawings and engineer's calcs? ### What guarantee do I get? ### Can I get an extension on a tight budget? ### Do you build extensions outside Barnsley? ## Related services View all services (https://johnsonsbuildingservicesyorkshire.co.uk/services) ### Loft Conversions Learn more → https://johnsonsbuildingservicesyorkshire.co.uk/services/loft-conversions ### Garage Conversions Learn more → https://johnsonsbuildingservicesyorkshire.co.uk/services/garage-conversions ### Renovations Learn more → https://johnsonsbuildingservicesyorkshire.co.uk/services/renovations Image: Beautifully completed traditional Yorkshire stone family home with modern rear extension at golden hour (https://johnsonsbuildingservicesyorkshire.co.uk/assets/cta-yorkshire-home-SjschQWs.jpg) ## Ready to get a fixed written quote for your house extensions? Tell us about your project. We'll arrange a free site visit and send your itemised written quote within 48 hours — no obligation. 07427 916462: +447427916462 Family-run · 20+ years building across Yorkshire · Fully insured · 10-year workmanship guarantee Call Now: +447427916462 Free Quote: https://johnsonsbuildingservicesyorkshire.co.uk/contact Essential cookies only — no tracking. Cookie Policy (https://johnsonsbuildingservicesyorkshire.co.uk/cookie-policy) ## Structured data ```json [ { "@context": "https://schema.org", "@type": "Organization", "@id": "https://johnsonsbuildingservicesyorkshire.co.uk/#organization", "name": "Johnsons Building Services (Yorkshire) Ltd", "url": "https://johnsonsbuildingservicesyorkshire.co.uk", "logo": "https://johnsonsbuildingservicesyorkshire.co.uk/favicon.png", "image": "https://johnsonsbuildingservicesyorkshire.co.uk/favicon.png", "telephone": "+44 7427 916462", "email": "enquiries@johnsonsbuildingservicesyorkshire.co.uk", "founder": { "@type": "Person", "name": "Daniel Glynn Johnson" }, "foundingDate": "2004", "address": { "@type": "PostalAddress", "streetAddress": "55 Copeland Road", "addressLocality": "Barnsley", "addressRegion": "South Yorkshire", "addressCountry": "GB" }, "sameAs": [ "https://johnsonsbuildingservicesyorkshire.co.uk", "https://www.facebook.com/profile.php?id=100064106648819" ] }, { "@context": "https://schema.org", "@type": "WebSite", "@id": "https://johnsonsbuildingservicesyorkshire.co.uk/#website", "url": "https://johnsonsbuildingservicesyorkshire.co.uk", "name": "Johnsons Building Services (Yorkshire) Ltd", "inLanguage": "en-GB", "publisher": { "@id": "https://johnsonsbuildingservicesyorkshire.co.uk/#organization" }, "potentialAction": { "@type": "SearchAction", "target": "https://johnsonsbuildingservicesyorkshire.co.uk/?s={search_term_string}", "query-input": "required name=search_term_string" } }, { "@context": "https://schema.org", "@type": "Service", "serviceType": "House Extensions", "name": "House Extensions in Barnsley & Yorkshire", "provider": { "@type": "GeneralContractor", "name": "Johnsons Building Services (Yorkshire) Ltd", "telephone": "+44 7427 916462", "address": { "@type": "PostalAddress", "streetAddress": "55 Copeland Road", "addressLocality": "Barnsley", "addressRegion": "South Yorkshire", "addressCountry": "GB" } }, "areaServed": [ "Barnsley", "Sheffield", "Leeds", "Wakefield", "Rotherham", "Doncaster", "Huddersfield", "Chesterfield", "Yorkshire" ], "description": "Single & double-storey house extensions in Barnsley and across Yorkshire. Family-run builders, 20+ years' experience, fixed written quote within 48 hours.", "url": "https://johnsonsbuildingservicesyorkshire.co.uk/services/house-extensions" }, { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "How much does a house extension cost in Barnsley?", "acceptedAnswer": { "@type": "Answer", "text": "As of 2026, expect £2,200–£2,800 per m² for a standard single-storey rear extension to a good specification. Double-storey works out cheaper per square metre at around £1,900–£2,400. We give you a fixed written price after the site visit so there are no surprises." } }, { "@type": "Question", "name": "How long does the build take?", "acceptedAnswer": { "@type": "Answer", "text": "A typical 4×6m single-storey extension takes 12–14 weeks from breaking ground to handover. Double-storey adds roughly 4 weeks. We give you a written week-by-week programme on day one." } }, { "@type": "Question", "name": "Do I need planning permission?", "acceptedAnswer": { "@type": "Answer", "text": "Many single-storey rear extensions fall under Permitted Development. Anything in a conservation area, on a listed building, or beyond the PD limits needs a full planning application. We handle the submission either way." } }, { "@type": "Question", "name": "Will I have to move out during the build?", "acceptedAnswer": { "@type": "Answer", "text": "Almost never for a rear or side extension — the existing house stays sealed until we knock through near the end. We always agree a 'breakthrough week' so you can plan around the dust." } }, { "@type": "Question", "name": "Do you handle architect's drawings and engineer's calcs?", "acceptedAnswer": { "@type": "Answer", "text": "Yes. We coordinate the architect, structural engineer and Building Control inspectors as part of the service. You only deal with us." } }, { "@type": "Question", "name": "What guarantee do I get?", "acceptedAnswer": { "@type": "Answer", "text": "A written 10-year workmanship guarantee, plus manufacturer warranties on the roof system, windows, doors and boiler. We also register the work with Building Control for the completion certificate." } }, { "@type": "Question", "name": "Can I get an extension on a tight budget?", "acceptedAnswer": { "@type": "Answer", "text": "Yes — by being decisive on spec early, by avoiding mid-build changes, and by accepting a slightly longer programme so we can phase the work. Honest conversation upfront saves thousands." } }, { "@type": "Question", "name": "Do you build extensions outside Barnsley?", "acceptedAnswer": { "@type": "Answer", "text": "We build right across South and West Yorkshire — Sheffield, Leeds, Wakefield, Rotherham, Doncaster, Huddersfield and Chesterfield. 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