Back-of-house extension drawings for West Cambridge homes — the glazed kitchen-diner across the rear, drawn to Cambridge City Council's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Cambridge City Council granted 90% of the householder planning decisions it made in its latest published year — 3 points above the 87% England-wide householder average. The architectural interest of the Conduit Head Road modernist group closely controls alterations and extensions, which is where a policy-literate drawing pack earns its keep. Its dominant Edwardian (1901–1910) and interwar (1918–1939) housing stock sets the design brief on most streets.
Class A and Class B set the thresholds — a rear dormer to 40m³ on a terrace or 50m³ on a semi or detached, and a single-storey rear extension to 3m on a terrace or 4m on a detached house — beyond which Cambridge City Council needs a full application. West Cambridge carries at least one Article 4 direction, and conservation areas including West Cambridge, Conduit Head Road and Storey's Way remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in West Cambridge is determined against an 8-week statutory target.
Conduit Head Road (a rare cluster of 1930s modernist houses inside its own conservation area), Storey's Way (spacious Arts-and-Crafts villas laid out by St John's College), Adams Road (large academic houses close to the science site), Grange Road (generous college and academic villas) and Madingley Road (detached houses on the western approach to the city) — these are the West Cambridge pockets our drawings cover most. Heritage designations here include West Cambridge, Conduit Head Road and Storey's Way. Cambridge City Council weighs each proposal against the Cambridge Local Plan 2018 and the emerging Greater Cambridge Local Plan, where the generous villa plots and mature planting on Storey's Way and Adams Road are protected from cramped infill. Some of the larger academic villas have been divided into flats for university staff, which hold no householder permitted-development rights.. On roofs the borough is hipped and gabled tile roofs on the Arts-and-Crafts villas and flat roofs on the Conduit Head Road modernist houses, over large detached Arts-and-Crafts and academic villas, 1930s modernist houses on Conduit Head Road and Edwardian and interwar houses.
The rear extension is the workhorse of West Cambridge home improvement — it is how a dark back kitchen becomes an open family room facing the garden. Because the borough is built largely from large detached Arts-and-Crafts and academic villas, 1930s modernist houses on Conduit Head Road and Edwardian and interwar houses, most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what Cambridge City Council scrutinises. The council reads the proposal against the Cambridge Local Plan 2018 and the emerging Greater Cambridge Local Plan, 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 architectural interest of the Conduit Head Road modernist group closely controls alterations and extensions, so the rear elevation is composed around it rather than corrected after an objection.
Where the property sits in a conservation area — West Cambridge, Conduit Head Road and Storey's Way among West Cambridge's — the larger-home extension route is switched off and even a modest rear addition needs consent. The west side sits within the West Cambridge, Conduit Head Road and Storey's Way conservation areas — the first two noted for their inter-war modernist and Arts-and-Crafts houses — and Article 4 directions remove permitted-development rights across them. We confirm the designation before the survey.
Many single-storey rear extensions in West Cambridge are permitted development and need no application. You will normally need to apply to Cambridge City 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 Cambridge City 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 Cambridge City Council's real householder decision record, taken from official planning statistics and refreshed as new data lands. Cambridge approves around 90% of applications, but on the west side the modernist and Arts-and-Crafts conservation areas and their generous plots are the decisive constraints. 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, England, 1 April 2025 - 31 March 2026). 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 Conduit Head Road, Storey's Way and Adams Road, 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 large detached arts-and-crafts and academic villas, 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 generous villa plots and mature planting on Storey's Way and Adams Road are protected from cramped infill. We keep the extension inside the daylight splays, set any glazed roof below the first-floor cill, and retain the garden depth Cambridge City 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 West Cambridge back-of-house projects come up most often:
Rear extension drawings for Conduit Head Road's a rare cluster of 1930s modernist houses inside its own conservation area — depth-checked, daylight-tested and drawn to Cambridge City Council's guidance.
Rear extension drawings for Storey's Way's spacious Arts-and-Crafts villas laid out by St John's College — depth-checked, daylight-tested and drawn to Cambridge City Council's guidance.
Rear extension drawings for Adams Road's large academic houses close to the science site — depth-checked, daylight-tested and drawn to Cambridge City Council's guidance.
Rear extension drawings for Grange Road's generous college and academic villas — depth-checked, daylight-tested and drawn to Cambridge City Council's guidance.
Rear extension drawings for Madingley Road's detached houses on the western approach to the city — depth-checked, daylight-tested and drawn to Cambridge City Council's guidance.
How far you can extend at the back in West Cambridge depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What Cambridge City 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 West Cambridge and Conduit Head Road and Article 4 streets need a full application.
A fixed process built around how Cambridge City Council validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your West Cambridge 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 Cambridge City 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 Cambridge City 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 Cambridge City 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 West Cambridge. You will need to involve Cambridge City 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 West Cambridge and Conduit Head Road, 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 Cambridge City 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 West Cambridge's conservation areas.
It is the daylight test Cambridge City 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. This applies to your West Cambridge address specifically.
A two-storey rear extension almost always needs a full householder application to Cambridge City 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. This applies to your West Cambridge address specifically.
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 Cambridge City Council's planning decision. We flag it early and can prepare the drawings a party-wall surveyor needs alongside the planning set. This applies to your West Cambridge address specifically.
We price each West Cambridge 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 Cambridge City 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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