Single-storey, double-storey, rear and side extension drawings for Castle homes — measured to Cambridge City Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.
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 Cambridge skyline guidance protects long views from Castle Hill across the historic city, which is where a policy-literate drawing pack earns its keep. Its dominant Georgian (1714–1837), Victorian (1837–1901) and Edwardian (1901–1910) housing stock sets the design brief on most streets.
Under Class B, a rear dormer stays permitted development up to 40m³ of added roof volume on a terrace or 50m³ on a semi-detached or detached house, while Class A allows a single-storey rear extension of 3m beyond the original rear wall on a terrace and 4m on a detached house before a full application is needed. Castle carries at least one Article 4 direction, and conservation areas including Castle and Victoria Road, Central and Storey's Way remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Castle is determined against an 8-week statutory target.
Castle Hill (Georgian and Victorian houses beside the Norman castle mound and Kettle's Yard), Victoria Road (Victorian terraces running north from the historic core), Storey's Way (spacious Arts-and-Crafts villas laid out by St John's College), Mount Pleasant (elevated Victorian and Edwardian houses above the city) and Huntingdon Road (large detached and academic houses on the northern approach) — these are the Castle pockets our drawings cover most. Heritage designations here include Castle and Victoria Road, Central 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 planned Arts-and-Crafts layout of Storey's Way constrains infill and the scale of extensions. Several of the larger Castle Hill and Huntingdon Road houses have been converted to flats, which carry no householder permitted-development rights.. On roofs the borough is pitched slate roofs on the Georgian and Victorian houses and gabled and hipped tile roofs on the Arts-and-Crafts villas, over Georgian and early-Victorian houses on Castle Hill, Victorian terraces along Victoria Road and Arts-and-Crafts villas on Storey's Way.
Castle homes come in a handful of recurring shapes, and each one points to a different extension. The borough is built largely from Georgian and early-Victorian houses on Castle Hill, Victorian terraces along Victoria Road and Arts-and-Crafts villas on Storey's Way, so a Victorian terrace usually wants a rear or side-return infill, while an interwar semi has room for a wider single-storey wrap or a two-storey side addition. Cambridge City Council judges every one of them against the Cambridge Local Plan 2018 and the emerging Greater Cambridge Local Plan, weighing footprint, height and the impact on the house next door before it looks at the elevations.
That is why the drawings decide the outcome. We set the extension depth against the permitted-development limits precisely, keep the eaves and ridge within the allowances, and plot the 45-degree daylight lines to the neighbours' windows so the case officer can see the amenity test is passed. The Cambridge skyline guidance protects long views from Castle Hill across the historic city, so we design around it from the first sketch rather than discover it at validation.
Castle also protects whole streets — Castle and Victoria Road, Central and Storey's Way among them. The Castle and Victoria Road conservation area — appraised in 2012 with a 2013 addendum — covers Castle Hill and its surrounds, adjoining the Central and Storey's Way areas, and Article 4 directions remove permitted-development rights across these streets. On designated land the larger-home extension route and most side extensions stop being permitted development, so we confirm your address against those layers before drawing a line.
Plenty of Castle extensions are permitted development and need no planning application — a single-storey rear extension within the depth and height limits is the common case. You will normally need to apply to Cambridge City Council if any of these apply:
We draw the footprint, the ridge and eaves heights and the neighbours' daylight on the page — the relationships Cambridge City Council's officers weigh first — and submit a validation-complete pack, whether that is a lawful development certificate, a prior-approval notification or a full householder application.
Below is Cambridge City Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Cambridge approves around 90% of applications, but the Castle and Victoria Road conservation area and the protected Castle Hill views are the decisive factors here. A complete, policy-literate extension pack anticipates those pressure points before submission, which is why professionally drawn applications are decided faster and refused less often than DIY ones.
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 Castle Hill, Victoria Road and Storey's Way, the extension that lands most often is the single-storey rear addition — a glazed kitchen-diner across the back of the house, kept within the permitted-development depth or taken to a full application where the ground floor wants more. On the borough's georgian and early-victorian houses on castle hill, a side-return infill frequently pairs with it to square off the plan; on wider arts-and-crafts villas on storey's way, a two-storey side or rear extension can add a bedroom above without swallowing the garden.
The planned Arts-and-Crafts layout of Storey's Way constrains infill and the scale of extensions. We size the extension to the amenity and daylight tests, match the roof and materials to the host house, and keep enough garden to satisfy Cambridge City Council's space standards — so the scheme answers the borough's questions before an objection can raise them. Where permitted-development rights are used up or removed, we prepare the householder application to the council's extension design guidance instead.
We draw extensions on every street in the borough. A few of the neighbourhoods where Castle projects come up most often:
Extension drawings for Castle Hill's Georgian and Victorian houses beside the Norman castle mound and Kettle's Yard — footprint-checked, daylight-tested and drawn to Cambridge City Council's guidance.
Extension drawings for Victoria Road's Victorian terraces running north from the historic core — footprint-checked, daylight-tested and drawn to Cambridge City Council's guidance.
Extension drawings for Storey's Way's spacious Arts-and-Crafts villas laid out by St John's College — footprint-checked, daylight-tested and drawn to Cambridge City Council's guidance.
Extension drawings for Mount Pleasant's elevated Victorian and Edwardian houses above the city — footprint-checked, daylight-tested and drawn to Cambridge City Council's guidance.
Extension drawings for Huntingdon Road's large detached and academic houses on the northern approach — footprint-checked, daylight-tested and drawn to Cambridge City Council's guidance.
The right extension in Castle depends on your house type and how much garden you can give up. This is how the main options compare on planning route and what they add.
| Extension type | Permitted development? | What it adds | What Cambridge City Council checks |
|---|---|---|---|
| Single-storey rear | Often, within 3m/4m depth (6m/8m via prior approval) | Bigger kitchen-diner across the back | Depth, height, neighbour daylight (45°) |
| Side-return infill | Sometimes, if within width and height limits | Squares off an L-shaped ground floor | Width vs the original house, glazing to boundary |
| Two-storey rear/side | No — full application | Extra bedroom or bathroom above | Bulk, overlooking, 7m rear-boundary gap |
| Wraparound (rear + side) | No — full application | Whole-width open-plan ground floor | Combined footprint and garden retained |
Route depends on your street — conservation areas such as Castle and Victoria Road and Central and Article 4 directions can remove permitted-development rights.
A fixed process built around how Cambridge City Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.
Tell us your Castle postcode and house type. We confirm your conservation and Article 4 status, how much permitted-development depth you have left, and score your odds against live Cambridge City Council decisions.
We measure the existing footprint, floor and eaves levels, boundary distances and the neighbours' window positions — the numbers the depth limits and daylight tests depend on.
Chartered designers develop the single-storey, two-storey or side extension to your brief, drawn inside the permitted-development limits or to Cambridge City Council's extension design guidance.
We submit the certificate, prior-approval notice or application, manage validation and case-officer queries, and revise the drawings free until Cambridge City Council issues its decision.
Not always. 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 Castle you will need to apply to Cambridge City Council for two-storey extensions, side extensions wider than half the house, anything forward of the front wall, deeper rear extensions under the larger-home prior-approval route, and any extension in a conservation area such as Castle and Victoria Road and Central.
Standard permitted development allows 3 metres on a terraced or semi-detached house and 4 metres on a detached one. The larger-home extension scheme can double that to 6 or 8 metres, but it needs a prior-approval notification to Cambridge City Council and a neighbour-consultation period, and it does not apply on designated land such as Castle's conservation areas. We confirm which route your property qualifies for before drawing.
Two-storey and double-storey extensions almost always need a full householder application to Cambridge City Council, because they fall outside permitted development on most homes. The council looks closely at bulk, overlooking of neighbours and the 7-metre gap a two-storey rear extension must keep from the rear boundary. We design to those tests and show the daylight and privacy angles on the drawings. This applies to your Castle address specifically.
A householder planning application in Castle runs to a statutory eight-week target, a larger-home prior-approval notification to around six weeks including the neighbour-consultation period, and a lawful development certificate to eight weeks. Incomplete submissions stall at validation, so we submit a complete pack and manage officer queries to keep the decision on schedule. Cambridge City Council is the decision-maker.
Yes — planning permission and building regulations are separate consents, and almost every extension needs both. Planning governs whether you can build it; building control governs how it is built, covering structure, insulation, drainage and fire safety. We prepare the building-regulations drawings alongside the planning set so Cambridge City Council's building control or an approved inspector can sign the work off. This applies to your Castle address specifically.
Every house and brief is different, so we price each Castle extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Cambridge City Council approves, and we tell you upfront whether your extension qualifies as permitted development. Call 020 7864 7245 to get started.
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Same fixed quotes, same fast drawings — wherever your project is.