Two-storey extension drawings for Cowley homes — bedroom above, living space below, drawn against the 3-metre projection and 7-metre boundary rules and to Oxford City Council's design guidance, delivered in days and revised free until your decision.
Oxford City Council granted 87% of the householder planning decisions it made in its latest published year — level with the 87% England-wide householder average. Much of Cowley's interwar housing shares a consistent building line and spacing, which officers protect so that paired and terraced houses keep their rhythm, which is where a policy-literate drawing pack earns its keep. Its dominant interwar (1918–1939) and postwar (1945–1970) 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. Cowley carries at least one Article 4 direction, and conservation areas including Temple Cowley and Oxford Stadium Sandy Lane remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Cowley is determined against an 8-week statutory target.
Temple Cowley (the historic village core, now a small conservation area amid interwar expansion), Florence Park (a 1933-1937 estate of rental houses built for Morris Cowley car workers, once nicknamed 'Little Rhondda'), Cowley Marsh (interwar terraces and semis on former marshland near the works), Rose Hill (a mid-20th-century estate on the southern slopes), Blackbird Leys (a large postwar estate built to house the growing car-plant workforce) and Church Cowley (older cottages around St James's church surrounded by interwar housing) — these are the Cowley pockets our drawings cover most. Heritage designations here include Temple Cowley and Oxford Stadium Sandy Lane. Oxford City Council weighs each proposal against the Oxford Local Plan 2036, where the Temple Cowley conservation area holds its older village frontages to tighter material and detailing standards than the surrounding estates. On roofs the borough is hipped roofs on the 1930s semis and gabled roofs on the interwar terraces, over 1930s interwar terraces and semis built for Morris Motors workers, the Florence Park estate of speculative rental houses from 1933-1937 and postwar and later infill around the former car works.
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. Cowley is largely 1930s interwar terraces and semis built for Morris Motors workers, the Florence Park estate of speculative rental houses from 1933-1937 and postwar and later infill around the former car works, and hipped roofs on the 1930s semis and gabled roofs on the interwar terraces 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.
Much of Cowley's interwar housing shares a consistent building line and spacing, which officers protect so that paired and terraced houses keep their rhythm. Oxford operates a city-wide Article 4 direction (in force since 25 February 2012) that removes the permitted right to change a family home into a small C4 house in multiple occupation, so an HMO conversion anywhere in the city needs planning permission — and the conservation areas layer further controls on frontages, roofs and windows on top.
Some two-storey rear extensions are permitted development. You will need a full application to Oxford 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 Oxford City Council checks first — then submit a validation-complete pack.
Below is Oxford City Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Oxford grants around 87% of the applications it decides, and in Cowley extensions to the uniform interwar Morris Motors housing turn mostly on spacing, building line and roof form. 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 Temple Cowley, Florence Park and Cowley Marsh, 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 1930s interwar terraces and semis built for morris motors workers, 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.
The Temple Cowley conservation area holds its older village frontages to tighter material and detailing standards than the surrounding estates. 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 Cowley. A few of the areas where they come up most often:
Two storey extension drawings for Temple Cowley — the historic village core, now a small conservation area amid interwar expansion — dimensioned against the 3m and 7m limits and drawn to Oxford City Council's guidance.
Two storey extension drawings for Florence Park — a 1933-1937 estate of rental houses built for Morris Cowley car workers, once nicknamed 'Little Rhondda' — dimensioned against the 3m and 7m limits and drawn to Oxford City Council's guidance.
Two storey extension drawings for Cowley Marsh — interwar terraces and semis on former marshland near the works — dimensioned against the 3m and 7m limits and drawn to Oxford City Council's guidance.
Two storey extension drawings for Rose Hill — a mid-20th-century estate on the southern slopes — dimensioned against the 3m and 7m limits and drawn to Oxford City Council's guidance.
Two storey extension drawings for Blackbird Leys — a large postwar estate built to house the growing car-plant workforce — dimensioned against the 3m and 7m limits and drawn to Oxford City Council's guidance.
Two storey extension drawings for Church Cowley — older cottages around St James's church surrounded by interwar housing — dimensioned against the 3m and 7m limits and drawn to Oxford 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 Oxford 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 Oxford City Council validates and decides two-storey applications.
Send us your Cowley postcode and garden depth. We measure the 7-metre boundary rule against your plot, confirm designation status, and score your odds against live Oxford 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 Oxford 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 Cowley, the 7-metre rule is what most commonly forces a full application to Oxford 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 Cowley gardens this is decisive, and we measure it on survey before any design work rather than discovering it at validation. Oxford City Council is the decision-maker.
Not under permitted development — two-storey side extensions always need a full application to Oxford 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 Cowley 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 Cowley address specifically. Oxford 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 Oxford City Council's planning decision, so we flag the notice period early and detail the junction on the drawings. This applies to your Cowley 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 Cowley address specifically. Oxford City Council is the decision-maker.
We quote each Cowley 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 Oxford City Council approves. Call 020 7864 7245 to start.
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