Back-of-house extension drawings for Cranborne & Alderholt homes — the glazed kitchen-diner across the rear, drawn to Dorset Council's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Dorset Council granted 95% of the householder planning decisions it made in its latest published year — 8 points above the 87% England-wide householder average. Cranborne & Alderholt contains Cranborne Conservation Area, Edmondsham Conservation Area, Wimborne St Giles Conservation Area conservation areas (Cranborne Conservation Area designated 1970), 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) 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 Dorset Council needs a full application. Cranborne & Alderholt carries at least one Article 4 direction, and conservation areas including Cranborne Conservation Area, Edmondsham Conservation Area and Wimborne St Giles Conservation Area remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Cranborne & Alderholt is determined against an 8-week statutory target.
Cranborne (conservation area designated in 1970), Edmondsham (conservation area designated in 1991), Wimborne St Giles (conservation area designated in 1975), Alderholt (civil parish within Cranborne & Alderholt), Cranborne (civil parish within Cranborne & Alderholt), Edmondsham (civil parish within Cranborne & Alderholt), Wimborne St. Giles (civil parish within Cranborne & Alderholt) and Woodlands (civil parish within Cranborne & Alderholt) — these are the Cranborne & Alderholt pockets our drawings cover most. Heritage designations here include Cranborne Conservation Area, Edmondsham Conservation Area and Wimborne St Giles Conservation Area. Dorset Council weighs each proposal against Dorset Council's adopted local plan and its householder design guidance, where the 2,160 homes here are 21% 1983-1992, 20% 1973-1982, 16% pre-1900, which is what sets the realistic roof and rear-projection options. On roofs the borough is trussed-rafter roofs typical of 1980s building and shallow trussed roofs typical of 1970s building, over 1980s estate houses (21% of 2,160 homes), 1970s and early-1980s houses (20%) and Victorian and earlier houses (16%).
Heritage designation is the single biggest variable in Cranborne & Alderholt, and it is address-specific: Cranborne (conservation area designated in 1970), Edmondsham (conservation area designated in 1991) and Wimborne St Giles (conservation area designated in 1975). Inside those boundaries permitted development is curtailed and Dorset 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, Cranborne & Alderholt takes in Alderholt, Cranborne, Edmondsham, Wimborne St. Giles and Woodlands. Dorset Council has 77 recorded Article 4 directions — check the address before assuming PD applies in Cranborne & Alderholt.
On stock, Cranborne & Alderholt is 1980s estate houses (21% of 2,160 homes), 1970s and early-1980s houses (20%) and Victorian and earlier houses (16%) — which is why trussed-rafter roofs typical of 1980s building and shallow trussed roofs typical of 1970s building govern what a loft or rear projection can realistically be. Dorset Council decided 1,261 householder applications in the latest published year and granted 95%, with 78% issued inside the eight-week target. We work from the council's own published record.
The full build-period split for Cranborne & Alderholt runs pre-1900 16% (350 homes), 1900-1918 6% (140 homes), 1919-1929 2% (40 homes), 1930-1939 2% (40 homes), 1945-1954 4% (80 homes), 1955-1964 3% (70 homes), 1965-1972 4% (80 homes), 1973-1982 20% (430 homes), 1983-1992 21% (460 homes), 1993-1999 9% (200 homes) and 2000-2008 4% (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.
Dorset Council also decides for Beacon, Beaminster, Blackmore Vale, Blandford, Chalk Valleys, Charminster St Mary's, Chickerell and Cranborne Chase, so a decision in Cranborne & Alderholt 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 1-3 The Lane, Kingston, Corfe Castle, 10 Cornwall Road, Swanage, 6 Burlington Road, Swanage and Avon Castle & Matchams Park Estate. 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 Cranborne & Alderholt and Dorset Council. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.
| Measure | Cranborne & Alderholt |
|---|---|
| Dwellings recorded | 2,160 |
| Built pre-1900 | 350 (16%) |
| Built 1900-1918 | 140 (6%) |
| Built 1919-1929 | 40 (2%) |
| Built 1930-1939 | 40 (2%) |
| Built 1945-1954 | 80 (4%) |
| Built 1955-1964 | 70 (3%) |
| Built 1965-1972 | 80 (4%) |
| Built 1973-1982 | 430 (20%) |
| Built 1983-1992 | 460 (21%) |
| Built 1993-1999 | 200 (9%) |
| Built 2000-2008 | 80 (4%) |
| Built before 1919 | 23% |
| Built 1919–1939 | 4% |
| Built 1945–2008 | 65% |
| Conservation areas in Cranborne & Alderholt | 3 (Cranborne Conservation Area, Edmondsham Conservation Area…) |
| Conservation areas district-wide | 311 |
| Article 4 directions recorded | 77 |
| Householder applications decided | 1,261 |
| Householder applications granted | 95% |
| Decided within 8 weeks | 78% |
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 Dorset Council's own, from MHCLG live table PS2 for the year to 31 March 2026.
The rear extension is the workhorse of Cranborne & Alderholt 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 (21% of 2,160 homes), 1970s and early-1980s houses (20%) and Victorian and earlier houses (16%), most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what Dorset Council scrutinises. The council reads the proposal against Dorset Council's adopted local plan and its householder design guidance, 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. Cranborne & Alderholt contains Cranborne Conservation Area, Edmondsham Conservation Area, Wimborne St Giles Conservation Area conservation areas (Cranborne Conservation Area designated 1970), 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 — Cranborne Conservation Area, Edmondsham Conservation Area and Wimborne St Giles Conservation Area among Cranborne & Alderholt's — the larger-home extension route is switched off and even a modest rear addition needs consent. Dorset Council has 77 recorded Article 4 directions — check the address before assuming PD applies in Cranborne & Alderholt. We confirm the designation before the survey.
Many single-storey rear extensions in Cranborne & Alderholt are permitted development and need no application. You will normally need to apply to Dorset 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 Dorset 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 Dorset Council's real householder decision record, taken from official planning statistics and refreshed as new data lands. Dorset Council granted 95% of its householder applications in the year to 31 March 2026, and Cranborne 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 Cranborne, Edmondsham and Wimborne St Giles, 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 (21% of 2,160 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 2,160 homes here are 21% 1983-1992, 20% 1973-1982, 16% pre-1900, 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 Dorset 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 Cranborne & Alderholt back-of-house projects come up most often:
Rear extension drawings for Cranborne's conservation area designated in 1970 — depth-checked, daylight-tested and drawn to Dorset Council's guidance.
Rear extension drawings for Edmondsham's conservation area designated in 1991 — depth-checked, daylight-tested and drawn to Dorset Council's guidance.
Rear extension drawings for Wimborne St Giles's conservation area designated in 1975 — depth-checked, daylight-tested and drawn to Dorset Council's guidance.
Rear extension drawings for Alderholt's civil parish within Cranborne & Alderholt — depth-checked, daylight-tested and drawn to Dorset Council's guidance.
Rear extension drawings for Cranborne's civil parish within Cranborne & Alderholt — depth-checked, daylight-tested and drawn to Dorset Council's guidance.
Rear extension drawings for Edmondsham's civil parish within Cranborne & Alderholt — depth-checked, daylight-tested and drawn to Dorset Council's guidance.
How far you can extend at the back in Cranborne & Alderholt depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What Dorset 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 Cranborne Conservation Area and Edmondsham Conservation Area and Article 4 streets need a full application.
A fixed process built around how Dorset Council validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your Cranborne & Alderholt 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 Dorset 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 Dorset 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 Dorset 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 Cranborne & Alderholt. You will need to involve Dorset 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 Cranborne Conservation Area and Edmondsham 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 Dorset 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 Cranborne & Alderholt's conservation areas.
It is the daylight test Dorset 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 Cranborne & Alderholt address specifically.
A two-storey rear extension almost always needs a full householder application to Dorset 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 Cranborne & Alderholt 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 Dorset 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 Cranborne & Alderholt address specifically.
We price each Cranborne & Alderholt 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 Dorset 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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