Wandsworth · SW11 · SW12 · SW15
House Extensions in Wandsworth
Premium south-west borough including Clapham and Putney — extension and loft hotspot. Single and double-storey extensions delivered as a fixed-scope design and build package.
Postcodes covered
Quick answer
Builderr delivers single-storey, double-storey and wraparound extensions across Wandsworth — SW11, SW12, SW15, SW17 and SW18. Typical Wandsworth extension cost £55,000–£185,000 over 10–22 weeks. Side returns dominate on Battersea and Clapham terraces, full-width rear extensions on Tooting and Earlsfield stock. Wandsworth determination typically runs 10–12 weeks against the 8-week target; we submit pre-app proposals to compress that timeline.
Wandsworth requires Design and Access Statements on conservation-area extensions and resists flat-roofed full-width additions on streets within Northcote and Heaver conservation zones.
Wandsworth
House Extensions specialists across Wandsworth.
We deliver house extensions projects across the full Wandsworth postcode set — SW11, SW12, SW15, SW17, SW18. Premium south-west borough including Clapham and Putney — extension and loft hotspot.
Every Wandsworth project includes a free desk-based planning assessment before we quote, so you know upfront whether permitted development, prior approval, or full planning applies to your specific address. Our local project manager for Wandsworth has detailed knowledge of the planning department's preferences, the conservation area boundaries, and the common construction details for the prevailing housing stock here.
Quotes for Wandsworth house extensions are fixed-scope after a site survey, valid for 60 days, and never carry provisional sums or open-ended day rates. Every project includes our 10-year structural warranty and 12-month defects period.
Planning in Wandsworth
Local planning rules for house extensions in Wandsworth.
Wandsworth contains over 40 conservation areas including Clapham Park, Wandsworth Common, Battersea Park, Northcote, Heaver, Magdalen, Putney, Tonsleys and Bellevue. Article 4 directions cover parts of Northcote and Heaver removing PD rights for external alterations. The council's residential design guide pushes mansards over rear dormers in conservation zones and requires detailed visual impact assessments for two-storey rear extensions. Wandsworth offers a paid pre-application advice service with strong recommendation to engage before submission. The borough is one of London's busier planning authorities — typical determination at 10–12 weeks against the 8-week statutory target.
Our planning team handles the full submission for Wandsworth addresses including drawings, Design and Access Statements where required, and pre-application consultation with the council. We tell you whether your house extension is permitted development, prior approval, or full planning before you sign anything.
Builderr vs other London builders.
The construction industry has a wide distribution of operators. Here's what changes between a directly-employed, fixed-scope outfit and the alternatives.
| Criterion | Builderr | Typical London builder | Cowboy outfit |
|---|---|---|---|
| Labour model | Directly employed team (PAYE) | Mixed subcontract gangs | Day-rate cash labour |
| Pricing | Fixed-scope itemised quote | Estimate + provisional sums | Verbal price + variations |
| Design & engineering | In-house architect + SE | Outsourced, separate billing | Builder draws on the back of an envelope |
| Planning + LDC handled | Yes — included in price | Often charged extra | Builder asks you to apply |
| Party wall surveyors | Instructed by us | Your responsibility | Skipped (illegal) |
| Building control | Plans + site inspections booked by us | Building Notice route | Not registered |
| Project management | Dedicated PM, weekly photo updates | Foreman doubles up | Owner-manager juggles 5 jobs |
| Payment schedule | Stage payments against signed-off milestones | Weekly invoices | Cash up front |
| Insurance | £10M PL + 10yr structural warranty | £2–5M PL only | No documented cover |
| Snags at handover | <3 typical | 20–30 typical | Walk-off mid-job common |
| Variation creep | 0% — fixed scope | +15–25% over original quote | +40%+ regularly |
Save £27,000–£60,750 on a house extension in Wandsworth.
Industry data (FMB, RICS, Which? Trusted Trader 2024) shows the average London construction project overruns by 18–22% on cost and 25–35% on time. Fixed-scope contracts with a single accountable team eliminate that variance. The savings above assume a typical project at £135,000.
FAQ
House Extensions in Wandsworth.
How much does a house extension cost in Wandsworth?
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Most house extensions projects in Wandsworth cost £50,000–£220,000 depending on size, spec and structural complexity. Inner London postcodes typically sit toward the upper end; outer borough projects trend mid-range. All Builderr Wandsworth quotes are fixed-price with no provisional sums.
Do I need planning permission for a house extension in Wandsworth?
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Planning rules vary across Wandsworth. We check permitted development eligibility, conservation area status and any Article 4 directions affecting your specific postcode before quoting. Many house extensions fall under permitted development, but conservation areas and listed buildings need full planning.
How long does a house extension take in Wandsworth?
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Typical timeline is 10–20 weeks on site, plus 4–8 weeks for design, structural engineering and approvals. If full planning is required (conservation areas, mansards, larger extensions), add 8–12 weeks for the planning decision before site start.
Do you have house extension references in Wandsworth?
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Yes — we maintain a live reference list for Wandsworth and can connect you with two or three completed clients within the borough. We've delivered projects across nearly every Wandsworth postcode since 2022, so most prospective clients can visit a completed project nearby.
What's included in a Builderr house extension quote in Wandsworth?
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Every Wandsworth quote covers structural design, party wall notices and surveyor coordination, planning or prior approval submission where required, building control, full build, snagging and a 10-year structural warranty. Kitchen units, sanitaryware and bespoke finishes are itemised separately so you can flex spec without losing fixed-price certainty on the build.
Other services in Wandsworth
Get a Wandsworth house extension quote.
Senior consultant call within one business hour. Free desk-based planning assessment for SW11, SW12, SW15 and surrounding postcodes. Fixed-scope price — no provisional sums.
