Rear dormer drawings for Marlborough West roofs — the box across the back slope that turns a low attic into a full-height room, drawn to Wiltshire Council's guidance and the volume limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Wiltshire Council granted 96% of the householder planning decisions it made in its latest published year — 9 points above the 87% England-wide householder average. Marlborough West contains AVEBURY, EAST KENNETT, LOCKERIDGE conservation areas (AVEBURY 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 interwar (1918–1939) 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 Wiltshire Council needs a full application. Marlborough West carries at least one Article 4 direction, and conservation areas including AVEBURY, EAST KENNETT and LOCKERIDGE remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Marlborough West is determined against an 8-week statutory target.
AVEBURY (conservation area designated in 1975), EAST KENNETT (conservation area designated in 1974), LOCKERIDGE (conservation area designated in 1985), MANTON (conservation area designated in 1985), MARLBOROUGH (conservation area designated in 1971), WEST KENNETT (conservation area designated in 1975), Avebury (civil parish within Marlborough West), Berwick Bassett (civil parish within Marlborough West), Marlborough (civil parish within Marlborough West), East Kennett (civil parish within Marlborough West), Fyfield (civil parish within Marlborough West) and West Overton (civil parish within Marlborough West) — these are the Marlborough West pockets our drawings cover most. Heritage designations here include AVEBURY, EAST KENNETT, LOCKERIDGE, MANTON, MARLBOROUGH and WEST KENNETT. Wiltshire Council weighs each proposal against Wiltshire Council's development plan and the design policies it applies to householder applications, where the 2,840 homes here are 24% pre-1900, 18% 1983-1992, 8% 1930-1939, 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 trussed-rafter roofs typical of 1980s building, over Victorian and earlier houses (24% of 2,840 homes), 1980s estate houses (18%) and 1930s semi-detached and detached houses (8%).
Heritage designation is the single biggest variable in Marlborough West, and it is address-specific: AVEBURY (conservation area designated in 1975), EAST KENNETT (conservation area designated in 1974), LOCKERIDGE (conservation area designated in 1985), MANTON (conservation area designated in 1985), MARLBOROUGH (conservation area designated in 1971) and WEST KENNETT (conservation area designated in 1975). Inside those boundaries permitted development is curtailed and Wiltshire 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, Marlborough West takes in Avebury, Berwick Bassett, Marlborough, East Kennett, Fyfield and West Overton. Wiltshire Council has 48 recorded Article 4 directions, removing permitted development for rear and side extensions and other roof alterations, including rooflights — check the address before assuming PD applies in Marlborough West.
On stock, Marlborough West is Victorian and earlier houses (24% of 2,840 homes), 1980s estate houses (18%) and 1930s semi-detached and detached houses (8%) — which is why steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building and trussed-rafter roofs typical of 1980s building govern what a loft or rear projection can realistically be. Wiltshire Council decided 1,779 householder applications in the latest published year and granted 96%, with 53% issued inside the eight-week target. We work from the council's own published record.
The full build-period split for Marlborough West runs pre-1900 24% (680 homes), 1900-1918 6% (160 homes), 1919-1929 0% (10 homes), 1930-1939 8% (220 homes), 1945-1954 2% (50 homes), 1955-1964 5% (140 homes), 1965-1972 7% (200 homes), 1973-1982 5% (140 homes), 1983-1992 18% (510 homes), 1993-1999 4% (110 homes) and 2000-2008 6% (160 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.
Wiltshire Council also decides for Aldbourne & Ramsbury, Amesbury West, Avon Valley, Box & Colerne, By Brook, Corsham Ladbrook, Corsham Pickwick and Corsham Without, so a decision in Marlborough West 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 Ashley, Avebury, Baydon 1 and Baydon 2. 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 Marlborough West and Wiltshire Council. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.
| Measure | Marlborough West |
|---|---|
| Dwellings recorded | 2,840 |
| Built pre-1900 | 680 (24%) |
| Built 1900-1918 | 160 (6%) |
| Built 1919-1929 | 10 (0%) |
| Built 1930-1939 | 220 (8%) |
| Built 1945-1954 | 50 (2%) |
| Built 1955-1964 | 140 (5%) |
| Built 1965-1972 | 200 (7%) |
| Built 1973-1982 | 140 (5%) |
| Built 1983-1992 | 510 (18%) |
| Built 1993-1999 | 110 (4%) |
| Built 2000-2008 | 160 (6%) |
| Built before 1919 | 30% |
| Built 1919–1939 | 8% |
| Built 1945–2008 | 46% |
| Conservation areas in Marlborough West | 6 (AVEBURY, EAST KENNETT…) |
| Conservation areas district-wide | 245 |
| Article 4 directions recorded | 48 |
| Householder applications decided | 1,779 |
| Householder applications granted | 96% |
| Decided within 8 weeks | 53% |
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 Wiltshire Council's own, from MHCLG live table PS2 for the year to 31 March 2026.
The box dormer is the workhorse loft, and most of Marlborough West is built for it — the borough runs to Victorian and earlier houses (24% of 2,840 homes), 1980s estate houses (18%) and 1930s semi-detached and detached houses (8%) under steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building and trussed-rafter roofs typical of 1980s building, and a flat-roofed box across the rear slope is the cheapest cubic metre of full-height space those roofs give up. Wiltshire Council tests the dormer against Wiltshire Council's development plan and the design policies it applies to householder applications, and because permitted development turns on a number, the volume you propose against the volume you have left is the first thing an officer or a certificate checks.
That is why the arithmetic goes on the drawings. We calculate the box against the 40- or 50-cubic-metre allowance, count any earlier roof enlargement into the total, hold the flat roof below the ridge and set the face back off the eaves so the dormer reads as subordinate. Marlborough West contains AVEBURY, EAST KENNETT, LOCKERIDGE conservation areas (AVEBURY designated 1975), so materials, fenestration and roof form are assessed against the appraisal, so the cheeks, the window line and the material are drawn to answer it rather than invite a query.
Where Marlborough West's streets are protected — AVEBURY, EAST KENNETT, LOCKERIDGE, MANTON, MARLBOROUGH and WEST KENNETT among them — the Class B dormer right is switched off and even a modest rear box needs consent. Wiltshire Council has 48 recorded Article 4 directions, removing permitted development for rear and side extensions and other roof alterations, including rooflights — check the address before assuming PD applies in Marlborough West. We confirm the designation before the box is sized.
Many rear dormers in Marlborough West are permitted development, but the volume and position decide it. You will normally need a full application to Wiltshire Council if any of these apply:
We draw the box within its volume allowance, the flat roof below the ridge and the face set back off the eaves — the three things a dormer stands or falls on — and submit a validation-complete pack, whether that is a lawful development certificate or a full householder application.
Below is Wiltshire Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Wiltshire Council granted 96% of its householder applications in the year to 31 March 2026, and AVEBURY shapes what is approved here. A dormer is decided on volume and set-back, so a pack that shows the calculation and the eaves detail is cleared 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 AVEBURY, EAST KENNETT and LOCKERIDGE, the dormer that goes through is the subordinate rear box: flat roof kept low, cheeks clad to recede, side windows obscure-glazed against overlooking, and the whole thing set back so the original eaves line still reads from the garden. On steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building, this returns a full-height double and en-suite from what was standing-room-only, usually inside the permitted-development volume.
The 2,840 homes here are 24% pre-1900, 18% 1983-1992, 8% 1930-1939, which is what sets the realistic roof and rear-projection options. We keep the box off the ridge, match the cheek material to the roof, and where the volume is already spent — or the street is designated — draw the dormer as a householder application composed to Wiltshire Council's roof-alteration guidance rather than push a certificate that would be refused.
We draw rear dormers on the terraced and semi-detached streets across the borough. A few of the neighbourhoods where Marlborough West dormers come up most often:
Dormer loft drawings for AVEBURY's conservation area designated in 1975 — volume-checked, set-back-detailed and drawn to Wiltshire Council's guidance.
Dormer loft drawings for EAST KENNETT's conservation area designated in 1974 — volume-checked, set-back-detailed and drawn to Wiltshire Council's guidance.
Dormer loft drawings for LOCKERIDGE's conservation area designated in 1985 — volume-checked, set-back-detailed and drawn to Wiltshire Council's guidance.
Dormer loft drawings for MANTON's conservation area designated in 1985 — volume-checked, set-back-detailed and drawn to Wiltshire Council's guidance.
Dormer loft drawings for MARLBOROUGH's conservation area designated in 1971 — volume-checked, set-back-detailed and drawn to Wiltshire Council's guidance.
Dormer loft drawings for WEST KENNETT's conservation area designated in 1975 — volume-checked, set-back-detailed and drawn to Wiltshire Council's guidance.
Whether a dormer in Marlborough West needs permission comes down to where it sits and how big the box is. This is how the cases compare.
| Dormer type | Permitted development? | What it gains | What Wiltshire Council checks |
|---|---|---|---|
| Rear box, within volume | Usually yes | Full-height room across the back | Volume total, 20cm eaves set-back |
| Rear box, over volume limit | No — full application | A larger room | How far over the allowance, bulk |
| Front or side dormer | No — full application | Light to the front rooms | Visibility from the street, character |
| Dormer in a conservation area | No — full application | Same space, extra scrutiny | Roof form and street appearance |
In conservation areas such as AVEBURY and EAST KENNETT, Class B dormer rights are removed and every dormer needs a full application.
A fixed process built around how Wiltshire Council validates and decides dormer applications — most drawings are submission-ready within seven days of survey.
Send us your Marlborough West postcode and roof type. We confirm your conservation and Article 4 status, work out how much permitted-development volume you have left, and score your odds against live Wiltshire Council decisions.
We measure ridge and eaves heights, roof pitch and the existing loft floor — the numbers the volume calculation, the set-back and the head heights depend on.
Chartered designers develop the box to your brief, drawn inside the Class B volume limits or, where those are exhausted or removed, to Wiltshire Council's roof-alteration guidance.
We submit the certificate or application, manage validation and case-officer queries, and revise the drawings free until Wiltshire Council issues its decision.
Often not. A rear box dormer within 40 cubic metres on a terrace, or 50 on a semi or detached house, set back at least 20 centimetres from the eaves and kept below the ridge, is usually permitted development. In Marlborough West you will need a full application to Wiltshire Council for a front or side dormer, a box that exceeds the volume, and any dormer in a conservation area such as AVEBURY and EAST KENNETT, where those rights are removed.
The permitted-development limit is a volume, not a footprint: 40 cubic metres of added roof space on a terraced house and 50 on a semi-detached or detached one, and any earlier loft enlargement counts against that total. In Marlborough West the box must also sit below the ridge and back from the eaves. We measure your roof and calculate the exact volume you have left before drawing. Wiltshire Council is the decision-maker.
Not under permitted development. A dormer on the front roof slope, or one facing a highway, always needs a full application to Wiltshire Council, because it changes how the house reads from the street. Rear box dormers are far more likely to be approved — or to be permitted development outright — which is why almost every Marlborough West dormer we draw sits on the back slope.
Often, on a terrace or semi. If the dormer or the loft steelwork meets the party wall with your neighbour, the Party Wall etc. Act applies and notice must be served before work starts — separately from Wiltshire Council's planning decision. We flag the party-wall junction on the drawings so a surveyor can be appointed early and the build is not held up. This applies to your Marlborough West address specifically.
If your dormer is permitted development, a lawful development certificate from Wiltshire Council is council-stamped proof of it — worth holding, because a buyer's solicitor will ask for it when you sell. We prepare and submit the certificate with the same measured drawing pack that shows the box within its volume allowance. This applies to your Marlborough West address specifically.
We price each Marlborough West dormer individually, because the roof pitch and the volume left vary house to house, and send a fixed, no-obligation quote within one working day. It covers the full drawing pack with free revisions until Wiltshire Council approves, and we confirm at the outset whether your box is permitted development or needs an application. Call 020 7864 7245 to start.
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