Back-of-house extension drawings for Eynsham and Cassington homes — the glazed kitchen-diner across the rear, drawn to West Oxfordshire District Council's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check first.
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.
The rear extension is the workhorse of Eynsham and Cassington home improvement — it is how a dark back kitchen becomes an open family room facing the garden. Because 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%), most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what West Oxfordshire District Council scrutinises. The council reads the proposal against West Oxfordshire District Council's development plan and the design policies it applies to householder applications, 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. 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 the rear elevation is composed around it rather than corrected after an objection.
Where the property sits in a conservation area — Cassington Conservation Area and Eynsham Conservation Area among Eynsham and Cassington's — the larger-home extension route is switched off and even a modest rear addition needs consent. 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. We confirm the designation before the survey.
Many single-storey rear extensions in Eynsham and Cassington are permitted development and need no application. You will normally need to apply to West Oxfordshire District 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 West Oxfordshire District 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 West Oxfordshire District Council's real householder decision record, taken 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. 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 Cassington, Eynsham and South Leigh and High Cogges, 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 late-1960s and early-1970s houses (18% of 3,040 homes), 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 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 keep the extension inside the daylight splays, set any glazed roof below the first-floor cill, and retain the garden depth West Oxfordshire District 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 Eynsham and Cassington back-of-house projects come up most often:
Rear extension drawings for Cassington's conservation area designated in 1992 — depth-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
Rear extension drawings for Eynsham's conservation area designated in 1975 — depth-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
Rear extension drawings for South Leigh and High Cogges's civil parish within Eynsham and Cassington — depth-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
Rear extension drawings for Cassington's civil parish within Eynsham and Cassington — depth-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
Rear extension drawings for Eynsham's civil parish within Eynsham and Cassington — depth-checked, daylight-tested and drawn to West Oxfordshire District Council's guidance.
How far you can extend at the back in Eynsham and Cassington depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What West Oxfordshire District 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 Cassington Conservation Area and Eynsham Conservation Area and Article 4 streets need a full application.
A fixed process built around how West Oxfordshire District Council validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your Eynsham and Cassington 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 West Oxfordshire District 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 West Oxfordshire District 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 West Oxfordshire District 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 Eynsham and Cassington. You will need to involve West Oxfordshire District 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 Cassington Conservation Area and Eynsham Conservation Area, 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 West Oxfordshire District 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 Eynsham and Cassington's conservation areas.
It is the daylight test West Oxfordshire District 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 Eynsham and Cassington address specifically.
A two-storey rear extension almost always needs a full householder application to West Oxfordshire District 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 Eynsham and Cassington 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 West Oxfordshire District 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 Eynsham and Cassington address specifically.
We price each Eynsham and Cassington 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 West Oxfordshire District 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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