Back-of-house extension drawings for Merton homes — the glazed kitchen-diner across the rear, drawn to Merton Council's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Merton Council granted 88% of the householder planning decisions it made in its latest published year — 1 point above the 87% England-wide householder average. The wooded, low-density character of Wimbledon Village and the Common caps bulk and roof enlargement on many plots, which is where a policy-literate drawing pack earns its keep. Its dominant Victorian (1837–1901), Edwardian (1901–1910) and interwar (1918–1939) housing stock sets the design brief on most streets.
The permitted-development ceilings are fixed: 40m³ of new roof volume for a terraced loft and 50m³ for a semi or detached house under Class B, plus a 3m single-storey rear extension on a terrace or 4m on a detached house under Class A. Merton carries at least one Article 4 direction, and conservation areas including Wimbledon Village, John Innes (Merton Park) and Mitcham Cricket Green remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Merton is determined against an 8-week statutory target.
Wimbledon (the leafy Village above Edwardian and Victorian streets), Merton Park (the John Innes estate of Arts and Crafts and Edwardian houses), Mitcham (interwar housing wrapped around the historic cricket green), Raynes Park (grids of Edwardian terraces west of the line), Colliers Wood (compact Victorian terraces along the Wandle) and Morden (1930s semi-detached suburbia and the St Helier fringe) — these are the Merton pockets our drawings cover most. Heritage designations here include Wimbledon Village, John Innes (Merton Park), Mitcham Cricket Green, Cottenham Park and Wimbledon West. Merton Council weighs each proposal against Merton Local Plan and the council's Design SPD, where the John Innes estate's Arts and Crafts detailing is protected in fine grain, down to porches, gates and boundary walls. Pockets of Wimbledon and Colliers Wood hold converted Victorian flats and maisonettes, which carry no householder permitted-development rights of their own.. On roofs the borough is pitched and gabled roofs on the terraces and villas and hipped roofs on the interwar semis, over Victorian and Edwardian terraces, detached Wimbledon villas and interwar semi-detached houses.
The rear extension is the workhorse of Merton home improvement — it is how a dark back kitchen becomes an open family room facing the garden. Because the borough is built largely from Victorian and Edwardian terraces, detached Wimbledon villas and interwar semi-detached houses, most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what Merton Council scrutinises. The council reads the proposal against Merton Local Plan and the council's Design SPD, and the first line an officer draws is the 45-degree splay from the neighbour's nearest window.
So the drawings live or die on geometry. We set the depth against the exact permitted-development figure, hold the eaves and the flat-roof or lantern build-up under the 4-metre height ceiling, and show the projection tested against both the 45-degree plan angle and the 25-degree section angle to the neighbouring windows. The wooded, low-density character of Wimbledon Village and the Common caps bulk and roof enlargement on many plots, so the rear elevation is composed around it rather than corrected after an objection.
Where the property sits in a conservation area — Wimbledon Village, John Innes (Merton Park), Mitcham Cricket Green, Cottenham Park and Wimbledon West among Merton's — the larger-home extension route is switched off and even a modest rear addition needs consent. Merton has withdrawn permitted-development rights on parts of the John Innes and Wimbledon Village conservation areas through Article 4 directions, so alterations that would be automatic elsewhere need a householder application here. We confirm the designation before the survey.
Many single-storey rear extensions in Merton are permitted development and need no application. You will normally need to apply to Merton Council, or use the larger-home prior-approval route, if any of these apply:
We draw the depth, the roof build-up and the daylight splays to each neighbour on the page — the tests Merton Council's officers apply first — and submit a validation-complete pack, whether that is a lawful development certificate, a larger-home prior-approval notice or a full householder application.
Below is Merton Council's real householder decision record, taken from official planning statistics and refreshed as new data lands. Merton consents the large majority of householder schemes, yet the leafy Wimbledon conservation areas and the uniform villa streets set close limits on how far roofs and side additions can go. Rear extensions turn most often on neighbour daylight and depth, so a drawing pack that proves those tests upfront is decided faster and refused less often than a DIY submission.
Source: MHCLG planning application statistics (householder decisions, rolling year). Compare every borough on our London approval-rate league table.
Tell us about your project and get a fixed, no-obligation quote back within one working day. If you don't need planning permission at all, we'll tell you that too — for free.
Across Wimbledon, Merton Park and Mitcham, the approved rear extension is typically a single-storey glazed box within the depth limit, roofed either flat with a lantern or in a shallow mono-pitch, and finished in brick or render to match the host wall. On the borough's victorian and edwardian terraces, keeping the projection to the permitted-development figure often avoids an application entirely; where owners want the full 6 metres, the larger-home route succeeds when the neighbour-consultation period passes without a sustained objection.
The John Innes estate's Arts and Crafts detailing is protected in fine grain, down to porches, gates and boundary walls. We keep the extension inside the daylight splays, set any glazed roof below the first-floor cill, and retain the garden depth Merton Council expects — so the back elevation answers the amenity case before a neighbour can lodge one. Two-storey rear extensions we draw with the 7-metre boundary gap and privacy screening resolved on the plan.
We draw rear extensions on every street in the borough. A few of the neighbourhoods where Merton back-of-house projects come up most often:
Rear extension drawings for Wimbledon's the leafy Village above Edwardian and Victorian streets — depth-checked, daylight-tested and drawn to Merton Council's guidance.
Rear extension drawings for Merton Park's the John Innes estate of Arts and Crafts and Edwardian houses — depth-checked, daylight-tested and drawn to Merton Council's guidance.
Rear extension drawings for Mitcham's interwar housing wrapped around the historic cricket green — depth-checked, daylight-tested and drawn to Merton Council's guidance.
Rear extension drawings for Raynes Park's grids of Edwardian terraces west of the line — depth-checked, daylight-tested and drawn to Merton Council's guidance.
Rear extension drawings for Colliers Wood's compact Victorian terraces along the Wandle — depth-checked, daylight-tested and drawn to Merton Council's guidance.
Rear extension drawings for Morden's 1930s semi-detached suburbia and the St Helier fringe — depth-checked, daylight-tested and drawn to Merton Council's guidance.
How far you can extend at the back in Merton depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What Merton Council checks |
|---|---|---|---|
| Standard permitted development | 3m terrace/semi · 4m detached | Lawful development certificate (optional) | Depth, 4m height, materials |
| Larger-home prior approval | 6m terrace/semi · 8m detached | Prior-approval notice + neighbour consultation | Neighbour objections on amenity |
| Full householder application | Beyond the above, or two-storey | Full planning permission | Daylight (45°/25°), bulk, garden retained |
| Conservation area | Case by case | Full planning permission | Character, roof form, boundary treatment |
The larger-home route is switched off on designated land — conservation areas such as Wimbledon Village and John Innes (Merton Park) and Article 4 streets need a full application.
A fixed process built around how Merton Council validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your Merton postcode and house type. We confirm your conservation and Article 4 status, how much rear-extension depth you have under permitted development, and score your odds against live Merton Council decisions.
We measure the original rear wall, floor and eaves levels, side and rear boundary distances and the neighbours' window positions — the numbers the depth limit and daylight splays depend on.
Chartered designers develop the single or two-storey rear extension to your brief, drawn inside the permitted-development limits or to Merton Council's extension design guidance, with the daylight angles shown.
We submit the certificate, prior-approval notice or application, handle validation and case-officer queries, and revise the drawings free until Merton Council issues its decision.
Often not. A single-storey rear extension up to 3 metres deep on a terrace or semi, or 4 metres on a detached house, and no higher than 4 metres, is usually permitted development in Merton. You will need to involve Merton Council for anything deeper via the larger-home route, for two-storey rear extensions, and for any rear extension in a conservation area such as Wimbledon Village and John Innes (Merton Park), where those permitted-development rights fall away.
The larger-home extension scheme lets a single-storey rear extension reach 6 metres on a terrace or semi, or 8 metres on a detached house — double the standard allowance. It is not automatic: you submit a prior-approval notification to Merton Council, neighbours are consulted, and if one objects on amenity grounds the council rules on it. It also does not apply on designated land such as Merton's conservation areas.
It is the daylight test Merton Council applies to protect neighbours. Drawn on plan, a line at 45 degrees from the midpoint of the neighbour's nearest ground-floor window should not be crossed by your extension; a companion 25-degree line is checked in section. If the projection breaches it, the extension is likely to be shortened or refused, so we test and prove it on the drawings before submission.
A two-storey rear extension almost always needs a full householder application to Merton Council, as it sits outside permitted development on most homes. The council checks that it stays at least 7 metres from the rear boundary, does not overbear the neighbours and avoids new overlooking. We resolve the boundary gap, privacy and daylight on the plans so the application is decided on its merits.
Frequently, yes. If the rear extension involves work to a shared wall, building up to the boundary, or excavating foundations near a neighbour's structure, the Party Wall etc. Act applies and you must serve notice — this is separate from Merton Council's planning decision. We flag it early and can prepare the drawings a party-wall surveyor needs alongside the planning set.
We price each Merton rear extension on its own footprint and send a fixed, no-obligation quote within one working day. It covers the full drawing pack with free revisions until Merton Council approves, and we confirm at the outset whether your extension is permitted development, needs prior approval, or a full application. Call 020 7864 7245 to begin.
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