Back-of-house extension drawings for Blean Forest homes — the glazed kitchen-diner across the rear, drawn to Canterbury City Council's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Canterbury City Council granted 97% of the householder planning decisions it made in its latest published year — 10 points above the 87% England-wide householder average. Blean Forest contains ALLCROFT GRANGE ( HACKINGTON ), AMERY COURT ( BLEAN ), BLEAN conservation areas (ALLCROFT GRANGE ( HACKINGTON ) designated 1995), so materials, fenestration and roof form are assessed against the appraisal, 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.
Class A and Class B set the thresholds — a rear dormer to 40m³ on a terrace or 50m³ on a semi or detached, and a single-storey rear extension to 3m on a terrace or 4m on a detached house — beyond which Canterbury City Council needs a full application. Blean Forest carries at least one Article 4 direction, and conservation areas including ALLCROFT GRANGE ( HACKINGTON ), AMERY COURT ( BLEAN ) and BLEAN remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Blean Forest is determined against an 8-week statutory target.
ALLCROFT GRANGE ( HACKINGTON ) (conservation area designated in 1995), AMERY COURT ( BLEAN ) (conservation area designated in 1995), BLEAN (conservation area designated in 1994), CANTERBURY ( WHITSTABLE ROAD ) Registered 04.12.1996 (conservation area designated in 1996), CANTERBURY AND WHITSTABLE RAILWAY (HACKINGTON & BLEAN) (conservation area designated in 1995), HOTHE COURT (conservation area designated in 1994), the Tyler Hill Conservation Area. Registered 27.03.1995 (conservation area designated in 1995), Hackington (civil parish within Blean Forest), Harbledown and Rough Common (civil parish within Blean Forest) and Blean (civil parish within Blean Forest) — these are the Blean Forest pockets our drawings cover most. Heritage designations here include ALLCROFT GRANGE ( HACKINGTON ), AMERY COURT ( BLEAN ), BLEAN, CANTERBURY ( WHITSTABLE ROAD ) Registered 04.12.1996, CANTERBURY AND WHITSTABLE RAILWAY (HACKINGTON & BLEAN), HOTHE COURT and the Tyler Hill Conservation Area. Registered 27.03.1995. Canterbury City Council weighs each proposal against the adopted Canterbury local plan and Canterbury City Council's design guidance for householder work, where the 2,640 homes here are 17% 1983-1992, 16% 1930-1939, 14% 1955-1964, which is what sets the realistic roof and rear-projection options. On roofs the borough is trussed-rafter roofs typical of 1980s building and hipped roofs with shallow pitches typical of 1930s building, over 1980s estate houses (17% of 2,640 homes), 1930s semi-detached and detached houses (16%) and late-1950s and early-1960s houses (14%).
Heritage designation is the single biggest variable in Blean Forest, and it is address-specific: ALLCROFT GRANGE ( HACKINGTON ) (conservation area designated in 1995), AMERY COURT ( BLEAN ) (conservation area designated in 1995), BLEAN (conservation area designated in 1994), CANTERBURY ( WHITSTABLE ROAD ) Registered 04.12.1996 (conservation area designated in 1996), CANTERBURY AND WHITSTABLE RAILWAY (HACKINGTON & BLEAN) (conservation area designated in 1995), HOTHE COURT (conservation area designated in 1994) and the Tyler Hill Conservation Area. Registered 27.03.1995 (conservation area designated in 1995). Inside those boundaries permitted development is curtailed and Canterbury City 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, Blean Forest takes in Hackington, Harbledown and Rough Common and Blean. Canterbury City Council has 463 recorded Article 4 directions — check the address before assuming PD applies in Blean Forest.
On stock, Blean Forest is 1980s estate houses (17% of 2,640 homes), 1930s semi-detached and detached houses (16%) and late-1950s and early-1960s houses (14%) — which is why trussed-rafter roofs typical of 1980s building and hipped roofs with shallow pitches typical of 1930s building govern what a loft or rear projection can realistically be. Canterbury City Council decided 580 householder applications in the latest published year and granted 97%, with 43% issued inside the eight-week target. We work from the council's own published record.
The full build-period split for Blean Forest runs pre-1900 11% (280 homes), 1900-1918 2% (40 homes), 1919-1929 2% (60 homes), 1930-1939 16% (420 homes), 1945-1954 8% (200 homes), 1955-1964 14% (370 homes), 1965-1972 10% (260 homes), 1973-1982 7% (190 homes), 1983-1992 17% (440 homes), 1993-1999 5% (130 homes) and 2000-2008 5% (130 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.
Canterbury City Council also decides for Chestfield, Gorrell, Herne & Broomfield, Heron, St Stephen's, Westgate, Wincheap and Little Stour & Adisham, so a decision in Blean Forest 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 1 AND 2 CHURCH COTTAGES, CHURCH LANE, NACKINGTON, 1 BOURNE COTTAGES, THE STREET, BISHOPSBOURNE, 1 BOX TREE COTTAGES, BOLTS HILL and 1 BUTTS COTTAGES, LOWER HARDRES. 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 Blean Forest and Canterbury City Council. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.
| Measure | Blean Forest |
|---|---|
| Dwellings recorded | 2,640 |
| Built pre-1900 | 280 (11%) |
| Built 1900-1918 | 40 (2%) |
| Built 1919-1929 | 60 (2%) |
| Built 1930-1939 | 420 (16%) |
| Built 1945-1954 | 200 (8%) |
| Built 1955-1964 | 370 (14%) |
| Built 1965-1972 | 260 (10%) |
| Built 1973-1982 | 190 (7%) |
| Built 1983-1992 | 440 (17%) |
| Built 1993-1999 | 130 (5%) |
| Built 2000-2008 | 130 (5%) |
| Built before 1919 | 12% |
| Built 1919–1939 | 18% |
| Built 1945–2008 | 65% |
| Conservation areas in Blean Forest | 7 (ALLCROFT GRANGE ( HACKINGTON ), AMERY COURT ( BLEAN )…) |
| Conservation areas district-wide | 98 |
| Article 4 directions recorded | 463 |
| Householder applications decided | 580 |
| Householder applications granted | 97% |
| Decided within 8 weeks | 43% |
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 Canterbury City Council's own, from MHCLG live table PS2 for the year to 31 March 2026.
The rear extension is the workhorse of Blean Forest home improvement — it is how a dark back kitchen becomes an open family room facing the garden. Because the borough is built largely from 1980s estate houses (17% of 2,640 homes), 1930s semi-detached and detached houses (16%) and late-1950s and early-1960s houses (14%), most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what Canterbury City Council scrutinises. The council reads the proposal against the adopted Canterbury local plan and Canterbury City Council's design guidance for householder work, 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. Blean Forest contains ALLCROFT GRANGE ( HACKINGTON ), AMERY COURT ( BLEAN ), BLEAN conservation areas (ALLCROFT GRANGE ( HACKINGTON ) designated 1995), 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 — ALLCROFT GRANGE ( HACKINGTON ), AMERY COURT ( BLEAN ), BLEAN, CANTERBURY ( WHITSTABLE ROAD ) Registered 04.12.1996, CANTERBURY AND WHITSTABLE RAILWAY (HACKINGTON & BLEAN), HOTHE COURT and the Tyler Hill Conservation Area. Registered 27.03.1995 among Blean Forest's — the larger-home extension route is switched off and even a modest rear addition needs consent. Canterbury City Council has 463 recorded Article 4 directions — check the address before assuming PD applies in Blean Forest. We confirm the designation before the survey.
Many single-storey rear extensions in Blean Forest are permitted development and need no application. You will normally need to apply to Canterbury City 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 Canterbury City 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 Canterbury City Council's real householder decision record, taken from official planning statistics and refreshed as new data lands. Canterbury City Council granted 97% of its householder applications in the year to 31 March 2026, and ALLCROFT GRANGE ( HACKINGTON ) 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 ALLCROFT GRANGE ( HACKINGTON ), AMERY COURT ( BLEAN ) and BLEAN, 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 1980s estate houses (17% of 2,640 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 2,640 homes here are 17% 1983-1992, 16% 1930-1939, 14% 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 Canterbury City 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 Blean Forest back-of-house projects come up most often:
Rear extension drawings for ALLCROFT GRANGE ( HACKINGTON )'s conservation area designated in 1995 — depth-checked, daylight-tested and drawn to Canterbury City Council's guidance.
Rear extension drawings for AMERY COURT ( BLEAN )'s conservation area designated in 1995 — depth-checked, daylight-tested and drawn to Canterbury City Council's guidance.
Rear extension drawings for BLEAN's conservation area designated in 1994 — depth-checked, daylight-tested and drawn to Canterbury City Council's guidance.
Rear extension drawings for CANTERBURY ( WHITSTABLE ROAD ) Registered 04.12.1996's conservation area designated in 1996 — depth-checked, daylight-tested and drawn to Canterbury City Council's guidance.
Rear extension drawings for CANTERBURY AND WHITSTABLE RAILWAY (HACKINGTON & BLEAN)'s conservation area designated in 1995 — depth-checked, daylight-tested and drawn to Canterbury City Council's guidance.
Rear extension drawings for HOTHE COURT's conservation area designated in 1994 — depth-checked, daylight-tested and drawn to Canterbury City Council's guidance.
How far you can extend at the back in Blean Forest depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What Canterbury City 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 ALLCROFT GRANGE ( HACKINGTON ) and AMERY COURT ( BLEAN ) and Article 4 streets need a full application.
A fixed process built around how Canterbury City Council validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your Blean Forest 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 Canterbury City 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 Canterbury City 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 Canterbury City 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 Blean Forest. You will need to involve Canterbury City 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 ALLCROFT GRANGE ( HACKINGTON ) and AMERY COURT ( BLEAN ), 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 Canterbury City 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 Blean Forest's conservation areas.
It is the daylight test Canterbury City 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 Blean Forest address specifically.
A two-storey rear extension almost always needs a full householder application to Canterbury City 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 Blean Forest 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 Canterbury City 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 Blean Forest address specifically.
We price each Blean Forest 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 Canterbury City 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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