Single-storey, double-storey, rear and side extension drawings for Eynsham and Cassington homes — measured to West Oxfordshire District Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.
West Oxfordshire District Council granted 97% of the householder planning decisions it made in its latest published year — 10 points above the 87% England-wide householder average. Eynsham and Cassington contains Cassington Conservation Area, Eynsham Conservation Area conservation areas (Cassington Conservation Area designated 1992), so materials, fenestration and roof form are assessed against the appraisal, which is where a policy-literate drawing pack earns its keep. Its dominant Victorian (1837–1901) and postwar (1945–1970) 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. Eynsham and Cassington carries at least one Article 4 direction, and conservation areas including Cassington Conservation Area and Eynsham Conservation Area remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Eynsham and Cassington is determined against an 8-week statutory target.
Cassington (conservation area designated in 1992), Eynsham (conservation area designated in 1975), South Leigh and High Cogges (civil parish within Eynsham and Cassington), Cassington (civil parish within Eynsham and Cassington) and Eynsham (civil parish within Eynsham and Cassington) — these are the Eynsham and Cassington pockets our drawings cover most. Heritage designations here include Cassington Conservation Area and Eynsham Conservation Area. West Oxfordshire District Council weighs each proposal against West Oxfordshire District Council's development plan and the design policies it applies to householder applications, where the 3,040 homes here are 18% 1965-1972, 15% pre-1900, 15% 1955-1964, which is what sets the realistic roof and rear-projection options. On roofs the borough is shallow-pitched roofs and integral garages typical of that period's building and steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building, over late-1960s and early-1970s houses (18% of 3,040 homes), Victorian and earlier houses (15%) and late-1950s and early-1960s houses (15%).
What is permitted in Eynsham and Cassington turns on designation first, so that is where we start: Cassington (conservation area designated in 1992) and Eynsham (conservation area designated in 1975). Inside those boundaries permitted development is curtailed and West Oxfordshire District Council assesses materials, window detail and roof form against the area's own appraisal, so a scheme that would be waved through two streets away can need a full application here.
Beyond the designated areas, Eynsham and Cassington takes in South Leigh and High Cogges, Cassington and Eynsham. West Oxfordshire District Council has 84 recorded Article 4 directions, removing permitted development for painting the exterior and gates, walls and fences — check the address before assuming PD applies in Eynsham and Cassington.
On stock, Eynsham and Cassington is late-1960s and early-1970s houses (18% of 3,040 homes), Victorian and earlier houses (15%) and late-1950s and early-1960s houses (15%) — which is why shallow-pitched roofs and integral garages typical of that period's building and steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building govern what a loft or rear projection can realistically be. West Oxfordshire District Council decided 616 householder applications in the latest published year and granted 97%, with 75% issued inside the eight-week target. We draw to that record rather than to a national average.
The full build-period split for Eynsham and Cassington runs pre-1900 15% (470 homes), 1900-1918 1% (20 homes), 1919-1929 3% (100 homes), 1930-1939 3% (100 homes), 1945-1954 4% (130 homes), 1955-1964 15% (470 homes), 1965-1972 18% (560 homes), 1973-1982 5% (160 homes), 1983-1992 10% (300 homes), 1993-1999 4% (110 homes) and 2000-2008 3% (80 homes). That distribution is why pre-1900 detailing dominates the drawings here, and it is measured from council-tax records rather than assumed from the street name.
West Oxfordshire District Council also decides for Alvescot and Filkins, Ascott and Shipton, Bampton and Clanfield, Ducklington, Milton-under-Wychwood, The Bartons, Witney Central and Woodstock and Bladon, so a decision in Eynsham and Cassington sits inside a wider pattern of decisions we track across the same authority — useful when an officer cites a precedent from the next area over.
The Article 4 directions recorded for this council include Article 4 ((Little Rollright), Article 4 (Cassington), Article 4 (Charlbury 1) and Article 4 (Crawley 1). Each removes a specific permitted-development right inside its own boundary, which is why the check is done on the address rather than on the town.
Published figures for Eynsham and Cassington and West Oxfordshire District Council. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.
| Measure | Eynsham and Cassington |
|---|---|
| Dwellings recorded | 3,040 |
| Built pre-1900 | 470 (15%) |
| Built 1900-1918 | 20 (1%) |
| Built 1919-1929 | 100 (3%) |
| Built 1930-1939 | 100 (3%) |
| Built 1945-1954 | 130 (4%) |
| Built 1955-1964 | 470 (15%) |
| Built 1965-1972 | 560 (18%) |
| Built 1973-1982 | 160 (5%) |
| Built 1983-1992 | 300 (10%) |
| Built 1993-1999 | 110 (4%) |
| Built 2000-2008 | 80 (3%) |
| Built before 1919 | 16% |
| Built 1919–1939 | 7% |
| Built 1945–2008 | 60% |
| Conservation areas in Eynsham and Cassington | 2 (Cassington Conservation Area, Eynsham Conservation Area) |
| Conservation areas district-wide | 50 |
| Article 4 directions recorded | 84 |
| Householder applications decided | 616 |
| Householder applications granted | 97% |
| Decided within 8 weeks | 75% |
Dwelling stock from VOA council-tax data at 31 March 2025; conservation-area and Article 4 counts from planning.data.gov.uk (MHCLG); decision figures are West Oxfordshire District Council's own, from MHCLG live table PS2 for the year to 31 March 2026.
Eynsham and Cassington homes come in a handful of recurring shapes, and each one points to a different extension. The borough is built largely from late-1960s and early-1970s houses (18% of 3,040 homes), Victorian and earlier houses (15%) and late-1950s and early-1960s houses (15%), 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. West Oxfordshire District Council judges every one of them against West Oxfordshire District Council's development plan and the design policies it applies to householder applications, 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. Eynsham and Cassington contains Cassington Conservation Area, Eynsham Conservation Area conservation areas (Cassington Conservation Area designated 1992), so materials, fenestration and roof form are assessed against the appraisal, so we design around it from the first sketch rather than discover it at validation.
Eynsham and Cassington also protects whole streets — Cassington Conservation Area and Eynsham Conservation Area among them. West Oxfordshire District Council has 84 recorded Article 4 directions, removing permitted development for painting the exterior and gates, walls and fences — check the address before assuming PD applies in Eynsham and Cassington. 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 Eynsham and Cassington 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 West Oxfordshire District Council if any of these apply:
We draw the footprint, the ridge and eaves heights and the neighbours' daylight on the page — the relationships West Oxfordshire District 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 West Oxfordshire District Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. West Oxfordshire District Council granted 97% of its householder applications in the year to 31 March 2026, and Cassington Conservation Area shapes what is approved 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 Cassington, Eynsham and South Leigh and High Cogges, 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 late-1960s and early-1970s houses (18% of 3,040 homes), a side-return infill frequently pairs with it to square off the plan; on wider late-1950s and early-1960s houses (15%), a two-storey side or rear extension can add a bedroom above without swallowing the garden.
The 3,040 homes here are 18% 1965-1972, 15% pre-1900, 15% 1955-1964, which is what sets the realistic roof and rear-projection options. 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 West Oxfordshire District 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 Eynsham and Cassington projects come up most often:
Extension drawings for Cassington's conservation area designated in 1992 — footprint-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
Extension drawings for Eynsham's conservation area designated in 1975 — footprint-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
Extension drawings for South Leigh and High Cogges's civil parish within Eynsham and Cassington — footprint-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
Extension drawings for Cassington's civil parish within Eynsham and Cassington — footprint-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
Extension drawings for Eynsham's civil parish within Eynsham and Cassington — footprint-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
The right extension in Eynsham and Cassington 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 West Oxfordshire District 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 Cassington Conservation Area and Eynsham Conservation Area and Article 4 directions can remove permitted-development rights.
A fixed process built around how West Oxfordshire District Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.
Tell us your Eynsham and Cassington 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 West Oxfordshire District 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 West Oxfordshire District 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 West Oxfordshire District 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 Eynsham and Cassington you will need to apply to West Oxfordshire District 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 Cassington Conservation Area and Eynsham Conservation Area.
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 West Oxfordshire District Council and a neighbour-consultation period, and it does not apply on designated land such as Eynsham and Cassington'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 West Oxfordshire District 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 Eynsham and Cassington address specifically.
A householder planning application in Eynsham and Cassington 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. West Oxfordshire District 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 West Oxfordshire District Council's building control or an approved inspector can sign the work off. This applies to your Eynsham and Cassington address specifically.
Every house and brief is different, so we price each Eynsham and Cassington extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until West Oxfordshire District 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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