Two-storey extension drawings for Petersfield homes — bedroom above, living space below, drawn against the 3-metre projection and 7-metre boundary rules and to Cambridge City Council's design guidance, delivered in days and revised free until your decision.
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 tight party-wall spacing of the artisan terraces controls the scale of rear and side additions, which is where a policy-literate drawing pack earns its keep. Its dominant Victorian (1837–1901) housing stock sets the design brief on most streets.
Before permission is required, Class B allows 40m³ of added loft volume on a terrace and 50m³ on a semi or detached house, and Class A allows a 3m single-storey rear extension on a terrace or 4m on a detached house. Petersfield carries at least one Article 4 direction, and conservation areas including Mill Road, The Kite and New Town and Glisson Road remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Petersfield is determined against an 8-week statutory target.
Gwydir Street (1860s artisan terraces, home to the Arts-and-Crafts David Parr House), Mill Road (the Victorian shopping street at the heart of the conservation area), Sturton Town (close-packed terraces built on land bought by developer Sturton), Norfolk Street (college-named terraces developed by Gonville and Caius and Corpus Christi) and Petersfield green (terraces facing directly onto the pavement around the green) — these are the Petersfield pockets our drawings cover most. Heritage designations here include Mill Road, The Kite and New Town and Glisson Road. Cambridge City Council weighs each proposal against the Cambridge Local Plan 2018 and the emerging Greater Cambridge Local Plan, where roof dormers are held to the unbroken slate rooflines that define the Mill Road character. Converted flats and student lets are widespread across the Mill Road terraces, and none of them hold householder permitted-development rights.. On roofs the borough is pitched slate roofs on the Victorian terraces and shallow-pitched roofs behind the Mill Road frontages, over dense Victorian artisan and railway-worker terraces, late-Victorian college-owned terraces and converted period flats.
Adding at first floor changes the question the case officer asks. A single-storey extension is judged mostly on daylight and garden loss; a two-storey extension is judged on overlooking, bulk against the neighbouring roofline, and whether it reads as part of the house or bolted onto it. Petersfield is largely dense Victorian artisan and railway-worker terraces, late-Victorian college-owned terraces and converted period flats, and pitched slate roofs on the Victorian terraces and shallow-pitched roofs behind the Mill Road frontages set what a matching roof actually means here.
The permitted-development route exists but is narrow: 3 metres of rear projection, a 7-metre stand-off from the rear boundary, eaves and ridge no higher than the original, and side-facing upper windows obscure-glazed and non-opening below 1.7 metres above floor level. Most two-storey schemes fail one of those, usually the 7-metre boundary rule on a shorter garden, and go in as a full application instead. We establish which route applies before designing, because it changes the drawing set.
The tight party-wall spacing of the artisan terraces controls the scale of rear and side additions. Petersfield lies within the Mill Road conservation area — designated in 1993 and covering the streets on the west side of the railway — with The Kite and New Town and Glisson Road adjoining, all subject to Article 4 controls on permitted development.
Some two-storey rear extensions are permitted development. You will need a full application to Cambridge City Council if any of these apply:
We set the projection and boundary distance on the site plan, prove the roof-pitch match on the elevations, and specify obscure glazing on the side windows — the three things Cambridge City Council checks first — then submit a validation-complete pack.
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 in Petersfield the dense terrace grain and the Mill Road conservation area shape what can realistically be built. Two-storey schemes attract more neighbour comment than any other householder work, so the overlooking and daylight case has to be made on the drawings.
Source: MHCLG planning application statistics (householder decisions, England, 1 April 2025 - 31 March 2026). Compare every borough on our London approval-rate league table.
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Across Gwydir Street, Mill Road and Sturton Town, the schemes that succeed set the first floor back from the ground floor, keep the ridge below the original, and treat the flank wall as blank or obscure-glazed. On dense victorian artisan and railway-worker terraces, matching the eaves line matters more than matching the brick: an extension that carries the existing eaves through reads as original even in a different material.
Roof dormers are held to the unbroken slate rooflines that define the Mill Road character. We draw the 45-degree daylight test from the neighbour's nearest habitable window, show the window positions in section, and set out the steel and foundation implications early — a two-storey extension changes the load path, so the structural design and the planning design have to be developed together rather than in sequence.
We draw two-storey extensions across Petersfield. A few of the areas where they come up most often:
Two storey extension drawings for Gwydir Street — 1860s artisan terraces, home to the Arts-and-Crafts David Parr House — dimensioned against the 3m and 7m limits and drawn to Cambridge City Council's guidance.
Two storey extension drawings for Mill Road — the Victorian shopping street at the heart of the conservation area — dimensioned against the 3m and 7m limits and drawn to Cambridge City Council's guidance.
Two storey extension drawings for Sturton Town — close-packed terraces built on land bought by developer Sturton — dimensioned against the 3m and 7m limits and drawn to Cambridge City Council's guidance.
Two storey extension drawings for Norfolk Street — college-named terraces developed by Gonville and Caius and Corpus Christi — dimensioned against the 3m and 7m limits and drawn to Cambridge City Council's guidance.
Two storey extension drawings for Petersfield green — terraces facing directly onto the pavement around the green — dimensioned against the 3m and 7m limits and drawn to Cambridge City Council's guidance.
The first-floor limits are tighter than the ground-floor ones. This is how the common cases compare.
| Scheme | Permitted development? | Deciding limit | What Cambridge City Council checks |
|---|---|---|---|
| Two-storey rear, 3m projection, 7m+ to boundary | Often yes | 3m projection / 7m boundary | Roof match, side-window glazing |
| Two-storey rear, under 7m to boundary | No — full application | Rear-boundary distance | Overlooking, daylight, garden loss |
| Two-storey side extension | No — full application | Side elevation | Gap to boundary, street rhythm |
| Two-storey wraparound | No — full application | Combined footprint | Bulk, massing, neighbour amenity |
| Any two-storey on designated land | No — full application | Designation | Character and appearance |
Limits from the GPDO 2015, Schedule 2, Part 1, Class A — two-storey rear extension conditions.
A fixed process built around how Cambridge City Council validates and decides two-storey applications.
Send us your Petersfield postcode and garden depth. We measure the 7-metre boundary rule against your plot, confirm designation status, and score your odds against live Cambridge City Council decisions.
We measure the original rear wall, eaves and ridge heights, garden depth and every neighbouring window that faces the site — the inputs the daylight and overlooking case is built from.
Chartered designers develop the two-storey addition to your brief with the roof and eaves resolved, and we coordinate the load path so the structural scheme and the planning scheme are the same building.
We submit the application, manage validation and case-officer queries, and revise the drawings free until Cambridge City Council issues its decision.
Often, but not always. A two-storey rear extension can be permitted development if it projects no more than 3 metres, sits at least 7 metres from the rear boundary, does not exceed the existing eaves and ridge, and has obscure-glazed non-opening side windows below 1.7 metres. In Petersfield, the 7-metre rule is what most commonly forces a full application to Cambridge City Council.
No part of a permitted-development two-storey rear extension may come within 7 metres of the boundary opposite the rear wall of the house. It exists to protect the neighbour behind you from being overlooked at first floor. On shorter Petersfield gardens this is decisive, and we measure it on survey before any design work rather than discovering it at validation. Cambridge City Council is the decision-maker.
Not under permitted development — two-storey side extensions always need a full application to Cambridge City Council. They are assessed on the gap to the boundary, whether the street's rhythm of spaces between houses survives, and whether the extension is subordinate to the original. Setting the first floor back from the front building line and down from the ridge is what usually makes the difference. This applies to your Petersfield address specifically.
Overlooking is the most common objection, and it is answerable on the drawings. We position habitable-room windows away from neighbouring gardens, obscure-glaze and fix shut anything on the flank below 1.7 metres, and show the sight lines in section. Where the geometry is tight, a rooflight or a high-level window gives the same daylight without the mutual overlooking that draws objections. This applies to your Petersfield address specifically. Cambridge City Council is the decision-maker.
Almost certainly. Excavating within 3 metres of a neighbouring structure and building on or up to the boundary both trigger the Party Wall etc. Act 1996, and a two-storey extension usually does both. It is entirely separate from Cambridge City Council's planning decision, so we flag the notice period early and detail the junction on the drawings. This applies to your Petersfield address specifically.
Yes. Adding a floor changes the load path from roof to foundation, so beams, padstones and foundation depths all need designing and calculating for building control. Planning and building regulations are separate consents, and the structural set is what building control assesses — we prepare both so the approved scheme is the buildable one. This applies to your Petersfield address specifically. Cambridge City Council is the decision-maker.
We quote each Petersfield two-storey extension individually, because plot depth, roof form and structural complexity vary house to house, and send a fixed, no-obligation quote within one working day. It covers the drawing pack with free revisions until Cambridge City Council approves. Call 020 7864 7245 to start.
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