The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with detailed technical phase, ideal for extensive Victorian terraced streets — the classic London side-return extension opportunity typical of Wandsworth.
Generously on the decision and slowly on the clock. Wandsworth approved 91.3% of householder applications, fourth highest in London, but 5.9% of its decisions ran past thirteen weeks and 9.4% of all applications were withdrawn before they were determined. Its Datahub set records 6,551 extension applications at 84% approved.
| Measure | Wandsworth | London |
|---|---|---|
| Householder approval rate | 91.3% | 83.0% |
| Householder decisions made | 3,107 | 77,680 |
| Decided beyond thirteen weeks | 5.9% | — |
| Applications withdrawn before decision | 9.4% | 7.4% |
| Extension applications in the Datahub | 6,551 | 84% approved |
| Larger-extension prior approvals granted | 31 | 51.7% of those determined |
| Conservation areas | 46 covering 1,061 ha | 1,141 across London |
Sources: decision counts from the MHCLG District Planning Application Statistics returns, PS1 and PS2, April 2023 to March 2026. The Datahub row was pulled on 15 August 2026 from the Planning London Datahub; being phrase-matched, it compares only within Wandsworth. Conservation area designations from planning.data.gov.uk, retrieved 1 September 2026.
For Wandsworth homeowners in Extensive Victorian terraced streets — the classic London side-return extension opportunity; Edwardian villas around the commons; 1930s semi-detached in Southfields, a house extension drawings package is the full measured-survey-to-submission drawing set London Borough of Wandsworth needs in order to determine an application: existing and proposed plans, elevations and sections at 1:100 and 1:50, a location and site plan, and the supporting statements the case officer asks for.
Prepared and reviewed by the chartered technologist team at Architectural Drawings London — MCIAT chartered, £2m PI insured.Last reviewed 2026-08-03.
The whole spectrum — rear extensions, side returns, wraparounds, double-storey, basement digs. Planning-led design with detailed technical phase, ideal for extensive Victorian terraced streets — the classic London side-return extension opportunity typical of Wandsworth.
Housing stock in Wandsworth: Extensive Victorian terraced streets — the classic London side-return extension opportunity; Edwardian villas around the commons; 1930s semi-detached in Southfields.
Character: Family-oriented, high side-return extension and loft conversion rates; planning department experienced with Victorian terrace modifications.
Article 4: a borough-wide Article 4 direction covers HMO conversions right across Wandsworth — which matters if the extension forms part of a change of use rather than work to a family house.
Before we quote: the house measured as built, a photographic record of it, and Article 4 plus conservation designations checked against your own address rather than against the borough in general.
Two or three concept options before anything is fixed: alternative plan layouts, different glazing strategies, more than one roof form.
What arrives: a site location plan, the house drawn as existing and as proposed, every affected elevation, the sections, and — on applications that demand one — a design and access statement.
Steel beam, foundation, lintel design. Chartered engineer sign-off.
Party Wall notices go out wherever the build touches a wall, floor or boundary held in common with a neighbour. Where the new foundations land within 3m of a public sewer, Thames Water has to issue a build-over agreement first — routine on Wandsworth's Victorian streets, where the sewer usually runs under the garden.
Single planning or regs submission.
Planning + building regs + structural.
Listed, conservation, complex sites.
Move the controls for an indicative figure. It anchors your budget — it is not a quote. Every project is priced after a free survey.
Build costs are separate and quoted by your contractor. See our published fees.
Wandsworth district by district: what we draw at each, which housing type dominates there, and the authority that validates an extension. Fee columns carry statutory national rates for 2026, not what we charge.
| Postcode | Area | Dominant stock | What it means for a house extension |
|---|---|---|---|
| SW4 | Clapham | Victorian terraces, Edwardian villas | SW4 is Clapham, shared between Lambeth and Wandsworth, with the boundary running close to the common. Houses on facing streets can therefore answer to different councils and different local policy. |
| SW8 | South Lambeth / Nine Elms | Victorian terraces, new-build apartments | SW8 spans South Lambeth and Nine Elms, decided by Lambeth or Wandsworth depending on the street. This is low ground beside the river, so expect flood-risk questions on anything at or below ground level whichever authority picks it up. |
| SW16 | Streatham / Norbury | Edwardian terraces, post-war flats | SW16 is the most divided district on this list, with parts of Streatham and Norbury falling to four separate authorities: Croydon, Merton, Lambeth and Wandsworth. Four councils means four validation checklists, so resolve the address before the drawing set is finalised rather than after it comes back. |
| SW19 | Wimbledon / Colliers Wood | Victorian villas, Edwardian terraces | SW19 splits between Merton and Wandsworth across Wimbledon and Colliers Wood. Check the address against both policies maps first: Merton's local validation requirements are not Wandsworth's, and a package built for one can be returned by the other. |
| SW11 | Battersea / Clapham Junction | Victorian terraces, mansion blocks | SW11 is Wandsworth throughout — Battersea and Clapham Junction. Dense Victorian terrace with shallow gardens, which tends to push a scheme towards a side return rather than a deep rear projection. |
| SW12 | Balham | Victorian and Edwardian terraces | SW12 covers Balham and crosses the Wandsworth–Lambeth line. The housing looks the same on both sides — late Victorian terrace, similar plot depths — which is precisely why owners here assume the wrong authority. |
| SW15 | Putney / Roehampton | Edwardian terraces, Victorian villas, mansion blocks | SW15 belongs to Wandsworth alone, covering Putney and Roehampton. The river frontage is the complication: a good deal of the low ground near the Thames falls inside Flood Zone 3, and the zone a plot sits in decides whether a Flood Risk Assessment goes in with the application. |
| SW17 | Tooting / Earlsfield | Edwardian terraces | SW17 takes in Tooting and Earlsfield and is shared with Merton. Confirm which council holds the address before drawings are issued; a validation refusal costs roughly as much time as an officer's request for further information. |
Between one Wandsworth street and the next the roof pitch shifts, the wall build-up shifts and the gardens get shorter. All three decide what an extension can actually deliver at a given address.
How designation changes a Wandsworth house extension: Wandsworth Council maintains 45 conservation areas, including Tonsley, Magdalen Park, Nightingale Triangle. Inside any of them a Wandsworth house extension cannot rely on permitted development, and the route becomes a £548 householder application determined in 8 weeks rather than a £249 prior approval in 6 weeks. Magdalen Park sets the tone for Wandsworth casework.
What Article 4 removes near Wandsworth: Article 4 for HMO conversions covering the whole borough. Before pricing a house extension we check whether the SW11 address is inside the mapped area, because Wandsworth Council draws the Wandsworth boundary street by street rather than across the whole of Wandsworth.
What Wandsworth is built from: Extensive Victorian terraced streets — the classic London side-return extension opportunity; Edwardian villas around the commons; 1930s semi-detached in Southfields. Family-oriented, high side-return extension and loft conversion rates; planning department experienced with Victorian terrace modifications. That mix decides the house extension route in Wandsworth more than the postcode does, and it is what a Wandsworth Council case officer reads first. A householder application costs £548 paid to Wandsworth Council direct, with 8 weeks to a decision once validated.
Sources for this Wandsworth house extension page: borough policies maps and conservation-area registers (2025–26), Royal Mail postcode district boundaries, the Town and Country Planning (Fees for Applications) (England) Regulations, the Town and Country Planning (General Permitted Development) (England) Order 2015 as amended, and the Party Wall etc. Act 1996.
Refusals in Wandsworth do not fare well on appeal. Of 373 householder appeals decided here since 2016, 125 were allowed, 244 dismissed and 4 split — 33.5% succeeding, against 39.0% across London. Read that for what it is. Only refused applicants appeal, and only the stubborn ones among those, so 33.5% is the chance of overturning a Wandsworth refusal, not the chance of getting permission: the council itself granted 2,836 householder applications out of 3,107 decided (MHCLG PS2). The appeal figure is the price of getting the first submission wrong.
Half of those appeals took longer than 81 days from start to decision, and that sits on top of the council's own determination period — which is the whole argument for getting the first application right. 12.6% of them, 47 cases, turned on a conservation area, so heritage argument is doing real work here. Every one of them, 100.0%, went to written representations — no hearing, no inquiry — so the case rested entirely on the drawings and the written statement.
Based on 373 householder appeals decided in Wandsworth. Casework figures published by the Planning Inspectorate under the Open Government Licence v3.0.
The questions Wandsworth owners put to us before they commission extension drawings, answered plainly and without the hedging.
Start a free quote →Most ordinary extensions here do sit inside permitted development: 3m of single-storey rear projection on an attached house, 4m if it stands detached, and a side return that stays inside half the width of the original house. Two things take that away. Article 4 directions withdraw the rights on particular streets, and flats, listed buildings and designated areas need full permission regardless. Which of those applies to your address is established before we quote, not after.
Under standard permitted development, a single-storey rear extension in Wandsworth may project 3m from an attached house or 4m from a detached one. The larger 6m and 8m projections go through prior approval under the neighbour consultation scheme instead. Flats hold no rights whatever. Listed buildings, and streets under an Article 4 direction, are outside the scheme too. The borough determined 143 larger-householder prior approvals over the three-year window and refused 29 of them, 20.3%, where London as a whole refused 24.9% (MHCLG PS1, retrieved 3 September 2026).
Two costs, and only one of them is ours. The fixed side covers planning drawings, building regulations and the structural calculations in a single quoted figure. The build is priced by your contractor per square metre, and that rate moves with access, ground conditions and specification. What decides whether either is worth spending is what the finished house is worth. Wandsworth's 2025 median sale was £650,000 across 4,984 transactions, level with 2024, with the upper quartile at £980,000 (Price Paid data, HM Land Registry, read on 3 September 2026). A side return normally costs less per m² than a double-storey rear, which is why it is the usual answer on a mid-terrace.
There is no Wandsworth-specific basement policy; the national framework governs, and basement conversions are generally acceptable subject to structure, drainage and flood risk. That last one is not a formality in this borough. Environment Agency mapping puts 17.88% of Wandsworth's 34.26 km2 into Flood Zone 3, and 21.13% into Zone 2 (EA flood map for planning; figures read on 3 September 2026), and which zone the site sits in is what determines whether a Flood Risk Assessment has to be submitted with the application. Within 3m of a public sewer you will also need a Thames Water build-over agreement.
On the Victorian terraces around Wandsworth Common the two usually go together. A side return takes the narrow alley down the flank of the house and folds it into the kitchen; a rear extension pushes back into the garden instead. Do both and you have a wraparound. Which of the three suits your plot comes down to garden depth and where the drainage runs, and that is settled at the free site visit.
Wandsworth's extensive Victorian terraced streets — the classic London side-return extension opportunity terraced and semi-detached stock typically suits rear single-storey extensions (kitchen-diners), side-return infill extensions, or double-storey rear. Wraparound extensions combine both directions for maximum gain. We recommend the most viable option at the free site visit.
We cover all Wandsworth postcodes — SW8, SW11, SW12, SW15, SW17, SW18, SW19 — with local surveyors. Survey appointments within 3 working days.
Decisions follow the London Plan alongside Wandsworth's own local policies. In practice that comes down to matching or complementing the existing materials, protecting the neighbours' light and privacy, and meeting Part L on the new fabric. Where a site carries a complicated planning history, we summarise the pre-application advice inside the submission so the case officer is not left reconstructing it.
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