Rear dormer drawings for St Mary's roofs — the box across the back slope that turns a low attic into a full-height room, drawn to Adur District Council's guidance and the volume limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Adur District Council granted 96% of the householder planning decisions it made in its latest published year — 9 points above the 87% England-wide householder average. St Mary's contains Shoreham-by-Sea, Southlands conservation areas (Shoreham-by-Sea 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), interwar (1918–1939) and postwar (1945–1970) housing stock sets the design brief on most streets.
The permitted-development ceilings are fixed: 40m³ of new roof volume for a terraced loft and 50m³ for a semi or detached house under Class B, plus a 3m single-storey rear extension on a terrace or 4m on a detached house under Class A. St Mary's carries at least one Article 4 direction, and conservation areas including Shoreham-by-Sea and Southlands remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in St Mary's is determined against an 8-week statutory target.
Shoreham-by-Sea (conservation area designated in 1971) and Southlands (conservation area designated in 1993) — these are the St Mary's pockets our drawings cover most. Heritage designations here include Shoreham-by-Sea and Southlands. Adur District Council weighs each proposal against the adopted Adur local plan and Adur District Council's design guidance for householder work, where the 2,480 homes here are 14% pre-1900, 13% 1930-1939, 10% 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 hipped roofs with shallow pitches typical of 1930s building, over Victorian and earlier houses (14% of 2,480 homes), 1930s semi-detached and detached houses (13%) and late-1960s and early-1970s houses (10%).
Before anything is drawn we check your address against the designations that apply in St Mary's: Shoreham-by-Sea (conservation area designated in 1971) and Southlands (conservation area designated in 1993). Inside those boundaries permitted development is curtailed and Adur District 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.
Adur District Council has 9 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 St Mary's.
On stock, St Mary's is Victorian and earlier houses (14% of 2,480 homes), 1930s semi-detached and detached houses (13%) and late-1960s and early-1970s houses (10%) — which is why steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building and hipped roofs with shallow pitches typical of 1930s building govern what a loft or rear projection can realistically be. Adur District Council decided 210 householder applications in the latest published year and granted 96%, with 60% issued inside the eight-week target. That decision record, not a national figure, is what we design to.
The full build-period split for St Mary's runs pre-1900 14% (350 homes), 1900-1918 7% (180 homes), 1919-1929 10% (240 homes), 1930-1939 13% (330 homes), 1945-1954 2% (50 homes), 1955-1964 4% (90 homes), 1965-1972 10% (250 homes), 1973-1982 5% (120 homes), 1983-1992 3% (80 homes), 1993-1999 4% (100 homes) and 2000-2008 9% (220 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.
Adur District Council also decides for Manor and Southwick Green, so a decision in St Mary's 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 Southdown Road, Southwick, Church Street, Shoreham-by-Sea, Kingston Buci Conservation Area and Land adjoining Steyning Road, Shoreham-by-Sea. 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 St Mary's and Adur District Council. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.
| Measure | St Mary's |
|---|---|
| Dwellings recorded | 2,480 |
| Built pre-1900 | 350 (14%) |
| Built 1900-1918 | 180 (7%) |
| Built 1919-1929 | 240 (10%) |
| Built 1930-1939 | 330 (13%) |
| Built 1945-1954 | 50 (2%) |
| Built 1955-1964 | 90 (4%) |
| Built 1965-1972 | 250 (10%) |
| Built 1973-1982 | 120 (5%) |
| Built 1983-1992 | 80 (3%) |
| Built 1993-1999 | 100 (4%) |
| Built 2000-2008 | 220 (9%) |
| Built before 1919 | 21% |
| Built 1919–1939 | 23% |
| Built 1945–2008 | 37% |
| Conservation areas in St Mary's | 2 (Shoreham-by-Sea, Southlands) |
| Conservation areas district-wide | 7 |
| Article 4 directions recorded | 9 |
| Householder applications decided | 210 |
| Householder applications granted | 96% |
| Decided within 8 weeks | 60% |
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 Adur District 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 St Mary's is built for it — the borough runs to Victorian and earlier houses (14% of 2,480 homes), 1930s semi-detached and detached houses (13%) and late-1960s and early-1970s houses (10%) under steeply pitched slate roofs, valley gutters and party parapets typical of pre-1900 building and hipped roofs with shallow pitches typical of 1930s building, and a flat-roofed box across the rear slope is the cheapest cubic metre of full-height space those roofs give up. Adur District Council tests the dormer against the adopted Adur local plan and Adur District Council's design guidance for householder work, 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. St Mary's contains Shoreham-by-Sea, Southlands conservation areas (Shoreham-by-Sea designated 1971), 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 St Mary's's streets are protected — Shoreham-by-Sea and Southlands among them — the Class B dormer right is switched off and even a modest rear box needs consent. Adur District Council has 9 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 St Mary's. We confirm the designation before the box is sized.
Many rear dormers in St Mary's are permitted development, but the volume and position decide it. You will normally need a full application to Adur District 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 Adur District Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Adur District Council granted 96% of its householder applications in the year to 31 March 2026, and Shoreham-by-Sea 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 Shoreham-by-Sea and Southlands, 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 2,480 homes here are 14% pre-1900, 13% 1930-1939, 10% 1965-1972, 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 Adur District 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 St Mary's dormers come up most often:
Dormer loft drawings for Shoreham-by-Sea's conservation area designated in 1971 — volume-checked, set-back-detailed and drawn to Adur District Council's guidance.
Dormer loft drawings for Southlands's conservation area designated in 1993 — volume-checked, set-back-detailed and drawn to Adur District Council's guidance.
Whether a dormer in St Mary's 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 Adur District 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 Shoreham-by-Sea and Southlands, Class B dormer rights are removed and every dormer needs a full application.
A fixed process built around how Adur District Council validates and decides dormer applications — most drawings are submission-ready within seven days of survey.
Send us your St Mary's 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 Adur District 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 Adur District Council's roof-alteration guidance.
We submit the certificate or application, manage validation and case-officer queries, and revise the drawings free until Adur District 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 St Mary's you will need a full application to Adur District Council for a front or side dormer, a box that exceeds the volume, and any dormer in a conservation area such as Shoreham-by-Sea and Southlands, 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 St Mary's 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. Adur District 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 Adur District 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 St Mary's 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 Adur District 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 St Mary's address specifically.
If your dormer is permitted development, a lawful development certificate from Adur District 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 St Mary's address specifically.
We price each St Mary's 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 Adur District 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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