Single-storey, double-storey, rear and side extension drawings for Dorset homes — measured to Dorset Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.
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. Dorset contains Abbotsbury Conservation Area, Acton Conservation Area 1, Acton Conservation Area 2 conservation areas (Abbotsbury Conservation Area designated 1971), 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. Dorset carries at least one Article 4 direction, and conservation areas including Abbotsbury Conservation Area, Acton Conservation Area 1 and Acton Conservation Area 2 remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Dorset is determined against an 8-week statutory target.
Abbotsbury (conservation area designated in 1971), Acton Conservation Area 1 (conservation area designated in 1975), Acton Conservation Area 2 (conservation area designated in 1975), Almer (conservation area designated in 1992), Alton Pancras (conservation area designated in 1990), Ashmore (conservation area designated in 1993), Beaminster Conservation Area 1 (conservation area designated in 1969), Beaminster Conservation Area 2 (conservation area designated in 1994), Beacon (ward of Dorset), Beaminster (ward of Dorset), Blackmore Vale (ward of Dorset), Blandford (ward of Dorset), Chalk Valleys (ward of Dorset), Charminster St Mary's (ward of Dorset), Chickerell (ward of Dorset) and Cranborne & Alderholt (ward of Dorset) — these are the Dorset pockets our drawings cover most. Heritage designations here include Abbotsbury Conservation Area, Acton Conservation Area 1, Acton Conservation Area 2, Almer Conservation Area, Alton Pancras Conservation Area, Ashmore Conservation Area, Beaminster Conservation Area 1 and Beaminster Conservation Area 2. Dorset Council weighs each proposal against Dorset Council's adopted local plan and its householder design guidance, where the 138,990 homes here are 21% pre-1900, 7% 1973-1982, 7% 1965-1972, which is what sets the realistic roof and rear-projection options. On roofs the borough is steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building and shallow trussed roofs typical of 1970s building, over Victorian and earlier houses (21% of 138,990 homes), 1970s and early-1980s houses (7%) and late-1960s and early-1970s houses (7%).
What is permitted in Dorset turns on designation first, so that is where we start: Abbotsbury (conservation area designated in 1971), Acton Conservation Area 1 (conservation area designated in 1975), Acton Conservation Area 2 (conservation area designated in 1975), Almer (conservation area designated in 1992), Alton Pancras (conservation area designated in 1990), Ashmore (conservation area designated in 1993), Beaminster Conservation Area 1 (conservation area designated in 1969) and Beaminster Conservation Area 2 (conservation area designated in 1994). 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, Dorset takes in Beacon, Beaminster, Blackmore Vale, Blandford, Chalk Valleys, Charminster St Mary's, Chickerell and Cranborne & Alderholt. Dorset Council has 77 recorded Article 4 directions — check the address before assuming PD applies in the district.
On stock, Dorset is Victorian and earlier houses (21% of 138,990 homes), 1970s and early-1980s houses (7%) and late-1960s and early-1970s houses (7%) — which is why steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 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 draw to that record rather than to a national average.
The full build-period split for Dorset runs pre-1900 3% (190 homes), 1900-1918 0% (30 homes), 1919-1929 0% (10 homes), 1930-1939 6% (350 homes), 1945-1954 3% (170 homes), 1955-1964 30% (1,850 homes), 1965-1972 33% (1,990 homes), 1973-1982 4% (260 homes), 1983-1992 5% (310 homes), 1993-1999 4% (220 homes) and 2000-2008 3% (170 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 & Alderholt, so a decision in Dorset 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 Dorset 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 | Dorset |
|---|---|
| Dwellings recorded | 138,990 |
| Built pre-1900 | 190 (3%) |
| Built 1900-1918 | 30 (0%) |
| Built 1919-1929 | 10 (0%) |
| Built 1930-1939 | 350 (6%) |
| Built 1945-1954 | 170 (3%) |
| Built 1955-1964 | 1,850 (30%) |
| Built 1965-1972 | 1,990 (33%) |
| Built 1973-1982 | 260 (4%) |
| Built 1983-1992 | 310 (5%) |
| Built 1993-1999 | 220 (4%) |
| Built 2000-2008 | 170 (3%) |
| Built before 1919 | 24% |
| Built 1919–1939 | 7% |
| Built 1945–2008 | 57% |
| Conservation areas in Dorset | 8 (Abbotsbury Conservation Area, Acton Conservation Area 1…) |
| 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.
Dorset homes come in a handful of recurring shapes, and each one points to a different extension. The borough is built largely from Victorian and earlier houses (21% of 138,990 homes), 1970s and early-1980s houses (7%) and late-1960s and early-1970s houses (7%), 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. Dorset Council judges every one of them against Dorset Council's adopted local plan and its householder design guidance, 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. Dorset contains Abbotsbury Conservation Area, Acton Conservation Area 1, Acton Conservation Area 2 conservation areas (Abbotsbury Conservation Area designated 1971), 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.
Dorset also protects whole streets — Abbotsbury Conservation Area, Acton Conservation Area 1, Acton Conservation Area 2, Almer Conservation Area, Alton Pancras Conservation Area, Ashmore Conservation Area, Beaminster Conservation Area 1 and Beaminster Conservation Area 2 among them. Dorset Council has 77 recorded Article 4 directions — check the address before assuming PD applies in the district. 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 Dorset 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 Dorset Council if any of these apply:
We draw the footprint, the ridge and eaves heights and the neighbours' daylight on the page — the relationships Dorset 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 Dorset Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Dorset Council granted 95% of 1,261 householder decisions in the year to 31 March 2026, 78% of them inside eight weeks. 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 Abbotsbury, Acton Conservation Area 1 and Acton Conservation Area 2, 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 victorian and earlier houses (21% of 138,990 homes), a side-return infill frequently pairs with it to square off the plan; on wider late-1960s and early-1970s houses (7%), a two-storey side or rear extension can add a bedroom above without swallowing the garden.
The 138,990 homes here are 21% pre-1900, 7% 1973-1982, 7% 1965-1972, 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 Dorset 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 Dorset projects come up most often:
Extension drawings for Abbotsbury's conservation area designated in 1971 — footprint-checked, daylight-tested and drawn to Dorset Council's guidance.
Extension drawings for Acton Conservation Area 1's conservation area designated in 1975 — footprint-checked, daylight-tested and drawn to Dorset Council's guidance.
Extension drawings for Acton Conservation Area 2's conservation area designated in 1975 — footprint-checked, daylight-tested and drawn to Dorset Council's guidance.
Extension drawings for Almer's conservation area designated in 1992 — footprint-checked, daylight-tested and drawn to Dorset Council's guidance.
Extension drawings for Alton Pancras's conservation area designated in 1990 — footprint-checked, daylight-tested and drawn to Dorset Council's guidance.
Extension drawings for Ashmore's conservation area designated in 1993 — footprint-checked, daylight-tested and drawn to Dorset Council's guidance.
The right extension in Dorset 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 Dorset 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 Abbotsbury Conservation Area and Acton Conservation Area 1 and Article 4 directions can remove permitted-development rights.
A fixed process built around how Dorset Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.
Tell us your Dorset 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 Dorset 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 Dorset 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 Dorset 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 Dorset you will need to apply to Dorset 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 Abbotsbury Conservation Area and Acton Conservation Area 1.
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 Dorset Council and a neighbour-consultation period, and it does not apply on designated land such as Dorset'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 Dorset 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.
A householder planning application in Dorset 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. Dorset 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 Dorset Council's building control or an approved inspector can sign the work off.
Every house and brief is different, so we price each Dorset extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Dorset 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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