Single-storey, double-storey, rear and side extension drawings for Somerset homes — measured to Somerset Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.
Somerset Council granted 94% of the householder planning decisions it made in its latest published year — 7 points above the 87% England-wide householder average. Somerset contains Alcombe, Alvington, Ansford conservation areas (Alcombe designated 1975), 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.
Under Class B, a rear dormer stays permitted development up to 40m³ of added roof volume on a terrace or 50m³ on a semi-detached or detached house, while Class A allows a single-storey rear extension of 3m beyond the original rear wall on a terrace and 4m on a detached house before a full application is needed. In conservation areas such as Alcombe, Alvington and Ansford those rights are removed, so we confirm your exact address before a line is drawn. A validated householder application in Somerset is determined against an 8-week statutory target.
Alcombe (conservation area designated in 1975), Alvington (conservation area designated in 2008), Ansford (conservation area designated in 1971), Ash Priors (conservation area designated in 1993), Ashbrittle (conservation area designated in 1993), Axbridge (conservation area designated in 1991), Batcombe (conservation area designated in 1978), Bathealton (conservation area designated in 1993), Blackdown & Neroche (ward of Somerset), Blackmoor Vale (ward of Somerset), Brent (ward of Somerset), Bridgwater South (ward of Somerset), Bridgwater West (ward of Somerset), Brympton (ward of Somerset), Burnham on Sea North (ward of Somerset) and Cannington (ward of Somerset) — these are the Somerset pockets our drawings cover most. Heritage designations here include Alcombe, Alvington, Ansford, Ash Priors, Ashbrittle, Axbridge, Batcombe and Bathealton. Somerset Council weighs each proposal against Somerset Council's development plan and the design policies it applies to householder applications, where the 177,300 homes here are 19% pre-1900, 6% 1973-1982, 6% 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 (19% of 177,300 homes), 1970s and early-1980s houses (6%) and late-1960s and early-1970s houses (6%).
Somerset's designated heritage is specific, and it is the first thing we check against your address: Alcombe (conservation area designated in 1975), Alvington (conservation area designated in 2008), Ansford (conservation area designated in 1971), Ash Priors (conservation area designated in 1993), Ashbrittle (conservation area designated in 1993), Axbridge (conservation area designated in 1991), Batcombe (conservation area designated in 1978) and Bathealton (conservation area designated in 1993). Inside those boundaries permitted development is curtailed and Somerset 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, Somerset takes in Blackdown & Neroche, Blackmoor Vale, Brent, Bridgwater South, Bridgwater West, Brympton, Burnham on Sea North and Cannington. No Article 4 direction is recorded for Somerset Council, but the district's 8 conservation areas still limit permitted development on those streets.
On stock, Somerset is Victorian and earlier houses (19% of 177,300 homes), 1970s and early-1980s houses (6%) and late-1960s and early-1970s houses (6%) — 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. Somerset Council decided 1,422 householder applications in the latest published year and granted 94%, with 74% issued inside the eight-week target. Those are the numbers our drawings are prepared against.
The full build-period split for Somerset 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.
Somerset Council also decides for Blackdown & Neroche, Blackmoor Vale, Brent, Bridgwater South, Bridgwater West, Brympton, Burnham on Sea North and Cannington, so a decision in Somerset 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.
Published figures for Somerset and Somerset Council. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.
| Measure | Somerset |
|---|---|
| Dwellings recorded | 177,300 |
| 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 | 22% |
| Built 1919–1939 | 8% |
| Built 1945–2008 | 56% |
| Conservation areas in Somerset | 8 (Alcombe, Alvington…) |
| Conservation areas district-wide | 178 |
| Article 4 directions recorded | 0 |
| Householder applications decided | 1,422 |
| Householder applications granted | 94% |
| Decided within 8 weeks | 74% |
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 Somerset Council's own, from MHCLG live table PS2 for the year to 31 March 2026.
Somerset 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 (19% of 177,300 homes), 1970s and early-1980s houses (6%) and late-1960s and early-1970s houses (6%), 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. Somerset Council judges every one of them against Somerset Council's development plan and the design policies it applies to householder applications, 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. Somerset contains Alcombe, Alvington, Ansford conservation areas (Alcombe designated 1975), 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.
Somerset also protects whole streets — Alcombe, Alvington, Ansford, Ash Priors, Ashbrittle, Axbridge, Batcombe and Bathealton among them. No Article 4 direction is recorded for Somerset Council, but the district's 8 conservation areas still limit permitted development on those streets. 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 Somerset 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 Somerset Council if any of these apply:
We draw the footprint, the ridge and eaves heights and the neighbours' daylight on the page — the relationships Somerset 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 Somerset Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Somerset Council granted 94% of 1,422 householder decisions in the year to 31 March 2026, 74% 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 Alcombe, Alvington and Ansford, 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 (19% of 177,300 homes), a side-return infill frequently pairs with it to square off the plan; on wider late-1960s and early-1970s houses (6%), a two-storey side or rear extension can add a bedroom above without swallowing the garden.
The 177,300 homes here are 19% pre-1900, 6% 1973-1982, 6% 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 Somerset 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 Somerset projects come up most often:
Extension drawings for Alcombe's conservation area designated in 1975 — footprint-checked, daylight-tested and drawn to Somerset Council's guidance.
Extension drawings for Alvington's conservation area designated in 2008 — footprint-checked, daylight-tested and drawn to Somerset Council's guidance.
Extension drawings for Ansford's conservation area designated in 1971 — footprint-checked, daylight-tested and drawn to Somerset Council's guidance.
Extension drawings for Ash Priors's conservation area designated in 1993 — footprint-checked, daylight-tested and drawn to Somerset Council's guidance.
Extension drawings for Ashbrittle's conservation area designated in 1993 — footprint-checked, daylight-tested and drawn to Somerset Council's guidance.
Extension drawings for Axbridge's conservation area designated in 1991 — footprint-checked, daylight-tested and drawn to Somerset Council's guidance.
The right extension in Somerset 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 Somerset 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 Alcombe and Alvington and Article 4 directions can remove permitted-development rights.
A fixed process built around how Somerset Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.
Tell us your Somerset 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 Somerset 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 Somerset 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 Somerset 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 Somerset you will need to apply to Somerset 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 Alcombe and Alvington.
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 Somerset Council and a neighbour-consultation period, and it does not apply on designated land such as Somerset'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 Somerset 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 Somerset 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. Somerset 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 Somerset Council's building control or an approved inspector can sign the work off.
Every house and brief is different, so we price each Somerset extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Somerset 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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Same fixed quotes, same fast drawings — wherever your project is.