--- title: "House Extensions in Tunbridge Wells | Single & Double Storey | Spectrum" description: "Single and double-storey extensions in Tunbridge Wells and Kent. Fixed quotes, structural engineering, Building Control sign-off, 1-year workmanship guarantee." lang: en-GB json-ld: | [ { "@context": "https://schema.org", "@type": "Organization", "@id": "/#organization", "name": "Spectrum Electrical & Building Ltd", "url": "/", "logo": "/__l5e/assets-v1/278be0ed-e1be-458b-a1b1-a08de471118f/spectrum-icon.png", "telephone": "07480 485988", "email": "spectrum.eb@mail.com", "address": { "@type": "PostalAddress", "streetAddress": "1 Sherwood Road", "addressLocality": "Tunbridge Wells", "addressRegion": "Kent", "postalCode": "TN2 3LB", "addressCountry": "GB" }, "areaServed": [ { "@type": "City", "name": "Kent" }, { "@type": "City", "name": "Tunbridge Wells" }, { "@type": "City", "name": "Tonbridge" }, { "@type": "City", "name": "Sevenoaks" }, { "@type": "City", "name": "Crowborough" }, { "@type": "City", "name": "Brenchley" }, { "@type": "City", "name": "Mayfield" }, { "@type": "City", "name": "Paddock Wood" }, { "@type": "City", "name": "Langton Green" } ], "sameAs": [ "https://maps.app.goo.gl/7AumDfwKajqS6xSU7" ] }, { "@context": "https://schema.org", "@type": "WebSite", "@id": "/#website", "name": "Spectrum Electrical & Building Ltd", "url": "/", "inLanguage": "en-GB", "publisher": { "@id": "/#organization" } }, { "@context": "https://schema.org", "@type": "Service", "serviceType": "House Extension Contractor", "name": "Extensions (Single & Double Storey)", "areaServed": { "@type": "City", "name": "Tunbridge Wells" }, "provider": { "@type": "LocalBusiness", "name": "Spectrum Electrical & Building Ltd", "telephone": "07480 485988", "address": { "@type": "PostalAddress", "streetAddress": "1 Sherwood Road", "addressLocality": "Tunbridge Wells", "postalCode": "TN2 3LB", "addressCountry": "GB" } }, "description": "Single and double-storey extensions in Tunbridge Wells and Kent. Fixed quotes, structural engineering, Building Control sign-off, 1-year workmanship guarantee." }, { "@context": "https://schema.org", "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "How much does a single-storey extension cost in Tunbridge Wells?", "acceptedAnswer": { "@type": "Answer", "text": "Costs vary by size, spec and complexity. Quotes are free. After a free on-site survey you'll receive a fixed itemised written quote, we aim for a 48-hour turnaround." } }, { "@type": "Question", "name": "How long does a double-storey extension take?", "acceptedAnswer": { "@type": "Answer", "text": "Most double-storey extensions run 14–20 weeks from groundworks to handover. Your written programme states every milestone." } }, { "@type": "Question", "name": "Do I need planning permission?", "acceptedAnswer": { "@type": "Answer", "text": "Many single-storey rear extensions fall under Permitted Development. Double-storey, side-return and conservation-area work usually needs full planning. We'll advise at survey and co-ordinate with your architect." } }, { "@type": "Question", "name": "Do you handle Party Wall agreements?", "acceptedAnswer": { "@type": "Answer", "text": "Yes. where boundary walls are affected we co-ordinate the Party Wall notices and surveyor process so the build can start on time." } }, { "@type": "Question", "name": "Are you fully insured?", "acceptedAnswer": { "@type": "Answer", "text": "Yes. £5m public liability and full employer's liability. Certificates supplied on request before works begin." } }, { "@type": "Question", "name": "Do you guarantee the work?", "acceptedAnswer": { "@type": "Answer", "text": "Yes. Building Control sign-off plus a 1-year Spectrum workmanship guarantee on every element we install." } }, { "@type": "Question", "name": "Can I live in the house during the build?", "acceptedAnswer": { "@type": "Answer", "text": "For most extensions, yes, we section off the works and keep services live overnight. Heaviest disruption is during the kitchen tie-in week." } }, { "@type": "Question", "name": "What areas do you cover?", "acceptedAnswer": { "@type": "Answer", "text": "Tunbridge Wells, Tonbridge, Sevenoaks, Crowborough, Brenchley, Mayfield, Paddock Wood, Langton Green and the wider Kent and East Sussex area." } } ] }, { "@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": "Extensions (Single & Double Storey)", "item": "/services/extensions" } ] } ] --- Tunbridge Wells, Kent Mon–Fri 8:00–17:00 [spectrum.eb@mail.com](mailto:spectrum.eb@mail.com)[07480 485988](tel:+447480485988) [![Spectrum Electrical & Building Ltd](/__l5e/assets-v1/a7c2b1aa-2941-4064-ad5b-d00433ea5395/spectrum-logo.png)](/) [About](/about) [Building Services](/services) [Other Services](/services) [Service Areas](/service-areas) [Our Work](/our-work)[Contact](/contact) [07480 485988](tel:+447480485988)[Request Estimate](/contact) ![Modern UK single-storey rear extension with bifold doors opening onto a garden](/assets/extensions-DJwVoyWX.jpg) Extensions · Single & Double Storey · Kent # Single & Double-Storey House Extensions across Tunbridge Wells & Kent Add the kitchen-diner, master suite or family room you actually need, designed, engineered and built by one local team, on a fixed price and a written programme. [Request my extension estimate](/contact) [07480 485988](tel:+447480485988) Fully insured to £5m · Company No. 15948972 · Free on-site survey · Building Control managed 1. [Home](/) 2. [Services](/services) 3. Extensions (Single & Double Storey) - Fixed-price contracts - Structural engineering in-house - Building Control filed by us - Party Wall co-ordination - 1-year workmanship guarantee Service overview ## What's involved in extensions (single & double storey). Plain-English breakdown, so you know exactly what you're paying for and why it matters before we set foot on site. ### What it is Single-storey rear and side extensions, wrap-arounds and double-storey extensions across Tunbridge Wells, Tonbridge, Sevenoaks and the wider Kent area. Foundations to finishes, groundworks, steels, blockwork, roofing, glazing, plastering, electrics, plumbing and decoration co-ordinated by one contractor. ### Who it's for Families outgrowing the house but staying for schools, homeowners adding a kitchen-diner with bi-folds, and buyers extending a recent purchase before moving in. ### When you need it Planning permission or Permitted Development drawings in hand and ready to price; structural engineer's calcs prepared; or at the architect stage and you want a builder costing it in parallel. ### Why it matters Extensions live and die on the steels, the foundations and the roof tie-in. We trial-pit, size the structure correctly, and sequence trades so the build runs to programme, not to weather and luck. The cost of doing nothing ## What goes wrong when this is ignored. Most extensions overrun on time and budget for the same handful of reasons, and almost all of them are avoidable at survey stage. ### Risks of waiting - Under-sized steels or pad stones cause deflection and cracking that only shows after plaster, expensive to remediate later. - Skimping on foundation depth on clay soils means heave or subsidence, especially near mature trees. - Poor roof tie-in to the existing house lets water track behind flashing within 12–18 months. - No Party Wall Award where required gives neighbours a legal right to halt the build mid-programme. ### Common mistakes - Choosing the cheapest quote without comparing what each builder has actually allowed for in foundations, steel and glazing. - Leaving glazing, kitchen and bathroom selections until mid-build, lead times push the handover by weeks. - Skipping a written programme so you can't hold anyone to a date. - Forgetting to budget for VAT, contingencies and the inevitable scope additions. Our process ## How the job actually runs. Same system every time. No improvising on your floor. 1. 01 ### Free on-site survey We walk the site, take measurements, review your drawings and discuss how you want to use the space day to day. 2. 02 ### Fixed written quote Itemised quote within 48 hours covering structure, trades, materials, programme and exclusions, no vague PC sums. 3. 03 ### Pre-start co-ordination Building Control submission, Party Wall notices where needed, structural engineer sign-off and a confirmed start date in writing. 4. 04 ### Build phase Single site supervisor, weekly progress reports, daily clean-down and one WhatsApp thread for every decision. 5. 05 ### Sign-off & handover Building Control completion certificate, snagging walk, warranties registered in your name and a 1-year Spectrum workmanship guarantee. What you get ## The outcomes that matter. ### One contractor, one invoice No managing nine trades or chasing VAT receipts after handover. ### Fixed price, not estimate Variations are quoted and signed before any extra work begins. ### Engineered properly Structural calcs and trial pits, not guesswork on the trowel. ### Tidy, respectful site Dust sheets, protected floors and neighbours kept informed, the house stays liveable. ### Backed by guarantees Building Control sign-off plus a 1-year workmanship guarantee in writing. ### Local references Recent finished extensions you can visit in TN, TN2 and TN4 postcodes. In depth ## Everything worth knowing before you book. The details a salesperson skips. Skim it, or read every word, both are useful. Questions on this? Talk to a Spectrum tradesman direct. [07480 485988](tel:+447480485988) ### Single-storey rear and side-return extensions The most common Tunbridge Wells extension, a 3–6m rear or side-return adding a kitchen-diner with bi-folds, a utility and often a downstairs WC. We handle groundworks, steel beams sized by a structural engineer, blockwork to match existing courses, flat or pitched roof with appropriate insulation, large-format glazing, underfloor heating, electrics, second-fix joinery and decoration. Typical programme 10–14 weeks. ### Double-storey and wrap-around extensions Double-storey extensions add a bedroom and en-suite above a downstairs reception. Wrap-arounds combine rear and side returns for transformational ground-floor remodelling. Both require careful tying-in to the existing roof, party walls and drains, we survey thoroughly so the quote stands up once we break ground. Typical programme 14–20 weeks. ### Planning, Permitted Development and Building Control We work to your architect's drawings, file Building Regulations applications, book inspections at each key stage (foundations, DPC, drains, structure, insulation, completion) and obtain the completion certificate. Where works fall under Permitted Development we'll advise and apply for a Lawful Development Certificate so the extension is documented for resale. Frequently asked ## Straight answers, no fluff. Can't see your question? Call [07480 485988](tel:+447480485988). How much does a single-storey extension cost in Tunbridge Wells? Costs vary by size, spec and complexity. Quotes are free. After a free on-site survey you'll receive a fixed itemised written quote, we aim for a 48-hour turnaround. How long does a double-storey extension take? Do I need planning permission? Do you handle Party Wall agreements? Are you fully insured? Do you guarantee the work? Can I live in the house during the build? What areas do you cover? Ready when you are ## Book your extensions (single & double storey) job today. Fixed written quote. Insured tradesmen. No upsell, no pressure. [Request my extension estimate](/contact) [07480 485988](tel:+447480485988) Fully insured to £5m Same-week starts 5-star rated locally Related services ## Other trades we cover. [View all services →](/services) [ ### General Building & Conversions Learn more ](/services/builder)[ ### Loft Conversions Learn more ](/services/loft-conversions)[ ### Refurbishments Learn more ](/services/refurbishments)[ ### New Builds Learn more ](/services/new-builds) ![Spectrum Electrical & Building Ltd](/__l5e/assets-v1/a7c2b1aa-2941-4064-ad5b-d00433ea5395/spectrum-logo.png) Trusted residential & commercial electrical and building experts in Tunbridge Wells, Kent. Over 20 years of skilled trade across the South East. Same-day service guaranteed. [Follow on Instagram ](https://www.instagram.com/spectrum_elec_and_build) ### Services - [General Building & Conversions](/services/builder) - [Extensions (Single & Double Storey)](/services/extensions) - [Loft Conversions](/services/loft-conversions) - [Refurbishments](/services/refurbishments) - [New Builds](/services/new-builds) - [Shop Fitting & Commercial Fit-Outs](/services/shop-fitting) - [Electrical Installations & Rewiring](/services/electrician) - [EV Charger Installation](/services/ev-chargers) - [Solar Panel Installation](/services/solar) - [Battery Storage Systems](/services/battery-storage) - [Plumbing](/services/plumber) - [Landscaping](/services/landscaping) ### Company - [About](/about) - [Service Areas](/service-areas) - [Reviews](/reviews) - [Contact](/contact) ### Contact - [07480 485988 ](tel:+447480485988) - [spectrum.eb@mail.com](mailto:spectrum.eb@mail.com) - 1 Sherwood Road Tunbridge Wells, Kent TN2 3LB - Mon–Fri 8:00–17:00 · Sat–Sun closed © 2026 Spectrum Electrical & Building Ltd. 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