Annexe and granny-flat drawings for Blean Forest homes — designed to stay ancillary to the main house rather than become a separate dwelling, drawn to Canterbury City Council's policies, delivered in days and revised free until your decision.
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.
Councils do not decide annexes on square metres. They decide whether, once built, the accommodation forms part of one planning unit with the main house or a second one beside it. Canterbury City Council looks at whether the garden is shared or divided, whether the annexe has its own street access and address, whether the occupier could live there entirely independently, and whether the two households would function as one. That is the whole case, and it is made or lost on the layout.
Blean Forest is largely 1980s estate houses (17% of 2,640 homes), 1930s semi-detached and detached houses (16%) and late-1950s and early-1960s houses (14%), which shapes the realistic options: converting part of the existing house, extending it, or building a detached unit in the garden. A detached annexe can sometimes sit under Class E as an outbuilding incidental to the enjoyment of the dwellinghouse — but sleeping accommodation is generally not "incidental", so a garden annexe with a bedroom usually needs its own permission rather than relying on outbuilding rights.
In Blean Forest's conservation areas — including ALLCROFT GRANGE ( HACKINGTON ) and AMERY COURT ( BLEAN ) — a garden building is also judged on its effect on the character of the area, which limits height and footprint before the use question is reached. Canterbury City Council has 463 recorded Article 4 directions — check the address before assuming PD applies in Blean Forest.
An annexe almost always needs an application to Canterbury City Council. Expect one where any of these apply:
We plan the annexe so its relationship to the main house is visible on the page — shared garden, connected access, a layout that reads as one household — and set out the case Canterbury City Council has to test, rather than leaving the officer to assume the worst.
Below is Canterbury City Council's real householder decision record, drawn 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. Annexe applications are decided on use as much as design, so the supporting case matters as much as the elevations.
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 ALLCROFT GRANGE ( HACKINGTON ), AMERY COURT ( BLEAN ) and BLEAN, the annexes that succeed keep one shared garden, take access past the main house rather than from the street, and are modest against the host building — single storey where the plot is overlooked, and set back from boundaries. On 1980s estate houses (17% of 2,640 homes), converting an integral garage or a rear ground floor is often approved more readily than a detached garden unit, because the ancillary relationship is self-evident.
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. Where Canterbury City Council grants permission, it commonly attaches a condition tying occupation of the annexe to the main dwelling. That condition is not a problem to be avoided — it is usually the mechanism that makes approval possible, and we draft the application on that basis rather than pretending the annexe is something it is not.
We draw annexes across Blean Forest. A few of the areas where multigenerational schemes come up most often:
Annexe and granny-flat drawings for ALLCROFT GRANGE ( HACKINGTON ) — conservation area designated in 1995 — planned to stay ancillary and drawn to Canterbury City Council's policies.
Annexe and granny-flat drawings for AMERY COURT ( BLEAN ) — conservation area designated in 1995 — planned to stay ancillary and drawn to Canterbury City Council's policies.
Annexe and granny-flat drawings for BLEAN — conservation area designated in 1994 — planned to stay ancillary and drawn to Canterbury City Council's policies.
Annexe and granny-flat drawings for CANTERBURY ( WHITSTABLE ROAD ) Registered 04.12.1996 — conservation area designated in 1996 — planned to stay ancillary and drawn to Canterbury City Council's policies.
Annexe and granny-flat drawings for CANTERBURY AND WHITSTABLE RAILWAY (HACKINGTON & BLEAN) — conservation area designated in 1995 — planned to stay ancillary and drawn to Canterbury City Council's policies.
Annexe and granny-flat drawings for HOTHE COURT — conservation area designated in 1994 — planned to stay ancillary and drawn to Canterbury City Council's policies.
Three similar buildings, three different consents. This is what separates them.
| What you build | Planning status | Key test | What Canterbury City Council checks |
|---|---|---|---|
| Garden room, no sleeping space | Often Class E permitted development | Incidental to the house | Height, footprint, boundary position |
| Annexe used by the household | Full application, usually with a tie condition | Ancillary use | Shared garden and access, layout |
| Self-contained unit, own access | New dwelling — full application | Separate planning unit | Policy on new homes, amenity, parking |
| Converted garage or ground floor | Often permitted, use still assessed | Whether use changes | Independence of the accommodation |
| Annexe on designated land | Full application | Designation | Character and appearance |
The ancillary/separate-dwelling distinction comes from section 55 of the Town and Country Planning Act 1990; outbuilding limits from the GPDO 2015, Schedule 2, Part 1, Class E.
A fixed process built around how Canterbury City Council tests the use question as well as the design.
Tell us who the annexe is for and where it would sit on the plot. We confirm designation status and tell you honestly whether the scheme reads as ancillary or as a separate dwelling in Blean Forest.
We measure the plot, the existing house and the access route, so the shared-garden and shared-access case can be drawn rather than asserted.
Chartered designers develop the annexe to your brief, with the layout, access and garden relationship arranged to support the ancillary case under Canterbury City Council's policies.
We submit the application with a supporting statement on use, manage validation and case-officer queries, and revise free until Canterbury City Council decides.
Almost always. Sleeping accommodation is generally not "incidental" to the enjoyment of a house, so it falls outside the outbuilding permitted-development right, and any annexe that could function independently raises a change-of-use question under section 55. In Blean Forest we prepare a full application to Canterbury City Council and make the ancillary case explicitly rather than hoping it is not asked.
A shared garden rather than a divided one, access through the main property rather than a separate street entrance, occupation by a member of the same household, and a physical and functional relationship with the main house. Canterbury City Council weighs those together — no single feature decides it, but a separate front door and a fenced-off garden together usually settle it against you. This applies to your Blean Forest address specifically.
Yes, subject to permission. A detached garden annexe is assessed on its scale against the plot, its effect on neighbours and the character of the area, and then on the use question. Keeping it single storey, set in from boundaries and served off the shared garden gives it the best prospect in Blean Forest, particularly near designated areas such as ALLCROFT GRANGE ( HACKINGTON ) and AMERY COURT ( BLEAN ). Canterbury City Council is the decision-maker.
Commonly, yes — a condition tying occupation of the annexe to the main dwelling, so it cannot be sold or let separately. That is normally what makes approval possible, because it removes the concern that a new independent home is being created without going through housing policy. The condition runs with the land, so it matters at resale, and we explain the implications before you commit. This applies to your Blean Forest address specifically. Canterbury City Council is the decision-maker.
Yes. A new annexe is new habitable accommodation, so structure, fire escape, insulation and ventilation all apply, and a detached annexe close to a boundary raises fire-spread requirements as well. Planning and building control are separate consents with separate submissions — we prepare both so the approved design is the one that can actually be built. This applies to your Blean Forest address specifically. Canterbury City Council is the decision-maker.
A householder application runs to an eight-week statutory target; where the council treats the annexe as creating a new unit it becomes a minor application with a thirteen-week target instead. Which route applies depends on how the use is characterised, which is precisely why the ancillary case is worth making properly at the outset. This applies to your Blean Forest address specifically. Canterbury City Council is the decision-maker.
We quote each Blean Forest annexe individually, because plot, access and whether you are converting or building new all change the work, and send a fixed, no-obligation quote within one working day. It covers the full drawing pack and supporting statement, with free revisions until Canterbury City Council approves. Call 020 7864 7245 to start.
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