Dormer, hip-to-gable and mansard loft conversion drawings for Colnbrook & Poyle homes — prepared to Slough Borough Council's design guidance, delivered in days and revised free until your decision lands, with a free approval-odds score first.
Slough Borough Council granted 82% of the householder planning decisions it made in its latest published year — 5 points below the 87% England-wide householder average. Colnbrook & Poyle contains the Colnbrook conservation area, so materials, fenestration and roof form are assessed against the appraisal, which is where a policy-literate drawing pack earns its keep. Its mixed housing stock sets the design brief street by street.
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. In conservation areas such as Colnbrook those rights are removed, so we confirm your exact address before a line is drawn. A validated householder application in Colnbrook & Poyle is determined against an 8-week statutory target.
Colnbrook (designated conservation area) and Colnbrook with Poyle (civil parish within Colnbrook & Poyle) — these are the Colnbrook & Poyle pockets our drawings cover most. Heritage designations here include Colnbrook. Slough Borough Council weighs each proposal against Slough Borough Council's adopted local plan and its householder design guidance, where the 3,130 homes here are 19% 1973-1982, 19% 2000-2008, 15% 1983-1992, which is what sets the realistic roof and rear-projection options. On roofs the borough is shallow trussed roofs typical of 1970s building and trussed-rafter roofs typical of 2000s building, over 1970s and early-1980s houses (19% of 3,130 homes), 2000s houses and apartments (19%) and 1980s estate houses (15%).
Before anything is drawn we check your address against the designations that apply in Colnbrook & Poyle: Colnbrook (designated conservation area). Inside those boundaries permitted development is curtailed and Slough Borough 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, Colnbrook & Poyle takes in Colnbrook with Poyle. No Article 4 direction is recorded for Slough Borough Council, but Colnbrook & Poyle's 1 conservation area still limit permitted development on those streets.
On stock, Colnbrook & Poyle is 1970s and early-1980s houses (19% of 3,130 homes), 2000s houses and apartments (19%) and 1980s estate houses (15%) — which is why shallow trussed roofs typical of 1970s building and trussed-rafter roofs typical of 2000s building govern what a loft or rear projection can realistically be. Slough Borough Council decided 417 householder applications in the latest published year and granted 82%, with 42% issued inside the eight-week target. That decision record, not a national figure, is what we design to.
The full build-period split for Colnbrook & Poyle runs pre-1900 5% (160 homes), 1900-1918 1% (30 homes), 1919-1929 2% (50 homes), 1930-1939 7% (220 homes), 1945-1954 0% (10 homes), 1955-1964 9% (290 homes), 1965-1972 13% (410 homes), 1973-1982 19% (610 homes), 1983-1992 15% (480 homes), 1993-1999 2% (60 homes) and 2000-2008 19% (580 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.
Slough Borough Council also decides for Langley St Mary's, so a decision in Colnbrook & Poyle 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 Colnbrook & Poyle and Slough Borough Council. These are the numbers that decide what is realistic on your street, so we work from them rather than from national averages.
| Measure | Colnbrook & Poyle |
|---|---|
| Dwellings recorded | 3,130 |
| Built pre-1900 | 160 (5%) |
| Built 1900-1918 | 30 (1%) |
| Built 1919-1929 | 50 (2%) |
| Built 1930-1939 | 220 (7%) |
| Built 1945-1954 | 10 (0%) |
| Built 1955-1964 | 290 (9%) |
| Built 1965-1972 | 410 (13%) |
| Built 1973-1982 | 610 (19%) |
| Built 1983-1992 | 480 (15%) |
| Built 1993-1999 | 60 (2%) |
| Built 2000-2008 | 580 (19%) |
| Built before 1919 | 6% |
| Built 1919–1939 | 9% |
| Built 1945–2008 | 78% |
| Conservation areas in Colnbrook & Poyle | 1 (Colnbrook) |
| Conservation areas district-wide | 5 |
| Article 4 directions recorded | 0 |
| Householder applications decided | 417 |
| Householder applications granted | 82% |
| Decided within 8 weeks | 42% |
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 Slough Borough Council's own, from MHCLG live table PS2 for the year to 31 March 2026.
Colnbrook & Poyle's roofs set the brief. The borough is built largely from 1970s and early-1980s houses (19% of 3,130 homes), 2000s houses and apartments (19%) and 1980s estate houses (15%), and its lofts sit under shallow trussed roofs typical of 1970s building and trussed-rafter roofs typical of 2000s building — the geometry that decides whether a rear dormer, a hip-to-gable or a mansard gives you the headroom you want. Slough Borough Council assesses loft proposals against Slough Borough Council's adopted local plan and its householder design guidance, and its case officers read each roof against the pair next door and the wider street before they read the plans.
That makes drawing quality decisive. We measure ridge and eaves heights, roof pitch and the existing stair, calculate the added volume against the permitted-development limits exactly, and show the workings on the drawings so Slough Borough Council can verify them. Colnbrook & Poyle contains the Colnbrook conservation area, so materials, fenestration and roof form are assessed against the appraisal, so we resolve it on the page rather than leave it for the case officer to raise.
Colnbrook & Poyle also carries protected streets — Colnbrook among them. No Article 4 direction is recorded for Slough Borough Council, but Colnbrook & Poyle's 1 conservation area still limit permitted development on those streets. We check your address against those designations before a line is drawn.
Many Colnbrook & Poyle loft conversions proceed without planning permission — a rear dormer within the permitted-development volume limits (40 cubic metres on a terrace, 50 on a semi or detached house) is usually lawful. You will normally need a full application to Slough Borough Council if any of these apply:
We draw the roof line, the ridge height and the neighbour's daylight on the page — the relationships Slough Borough Council's officers check first — and submit a validation-complete pack, whether that is a lawful development certificate or a full householder application.
Below is Slough Borough Council's real householder decision record, pulled from official planning statistics and updated as new data lands. Slough Borough Council granted 82% of its householder applications in the year to 31 March 2026, and Colnbrook shapes what is approved here. Professionally prepared loft drawings anticipate those pressure points before submission, which is why complete, policy-literate packs are decided faster and refused less often than DIY applications.
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 Colnbrook and Colnbrook with Poyle, the recurring loft is the rear dormer — a box across the back roof slope that turns a cramped attic into a full-height double bedroom and en-suite. On shallow trussed roofs typical of 1970s building, that is usually the most efficient use of the roof; where the stock is trussed-rafter roofs typical of 2000s building, a hip-to-gable followed by a rear dormer unlocks far more space, though it needs a full application.
The 3,130 homes here are 19% 1973-1982, 19% 2000-2008, 15% 1983-1992, which is what sets the realistic roof and rear-projection options. We draw the dormer inside the volume allowance, keep the flat-roof build-up below the ridge, and set the face back from the eaves as the rules require — so the pack answers Slough Borough Council's questions before they are asked. Where permitted-development rights are exhausted or removed, we prepare a householder application composed to the borough's roof-alteration guidance instead.
We draw loft conversions on every street in the borough. A few of the neighbourhoods where Colnbrook & Poyle roofs come up most often:
Loft conversion drawings for Colnbrook's designated conservation area — measured, volume-checked and drawn to Slough Borough Council's guidance.
Loft conversion drawings for Colnbrook with Poyle's civil parish within Colnbrook & Poyle — measured, volume-checked and drawn to Slough Borough Council's guidance.
The right loft in Colnbrook & Poyle depends on your roof. This is how the main types compare on planning route and the space they add.
| Loft type | Permitted development? | Space & headroom | What Slough Borough Council checks |
|---|---|---|---|
| Rear dormer | Usually yes, within volume limits | Full-height double room at the back | Volume, set-back from eaves, ridge height |
| Hip-to-gable | No — full application | Extends the whole side of the roof | Roof bulk and the symmetry of the pair |
| Mansard | No — full application | Maximum floor area across the roof | Street character, especially in conservation areas |
| Rooflights only | Usually yes (Class C) | Light and headroom, no extra footprint | Whether rooflights sit within the existing slope |
Route depends on your street — conservation areas such as Colnbrook and Article 4 directions can remove permitted-development rights.
A fixed process built around how Slough Borough Council validates and decides householder loft applications — most drawings are submission-ready within seven days of survey.
Tell us your Colnbrook & Poyle postcode and roof type. We confirm your conservation and Article 4 status, how much permitted-development volume you have left, and score your odds against live Slough Borough Council decisions.
We measure ridge and eaves heights, roof pitch, joist levels and the existing stair — the numbers the volume calculation and head heights depend on.
Chartered designers develop the dormer, hip-to-gable or mansard to your brief, drawn inside the Class B limits or to Slough Borough Council's roof-alteration guidance.
We submit the certificate or application, manage validation and case-officer queries, and revise the drawings free until Slough Borough Council issues its decision.
Often not. A rear dormer within 40 cubic metres on a terrace, or 50 on a semi-detached or detached house, set back from the eaves and no higher than the ridge, is usually permitted development. In Colnbrook & Poyle the main exceptions are hip-to-gable conversions, dormers visible from the highway, and homes in conservation areas such as Colnbrook or on streets with an Article 4 direction. Slough Borough Council is the decision-maker.
Generally no. In conservation areas including Colnbrook, Class B permitted-development rights for lofts are removed, so a rear dormer that would be lawful elsewhere needs a full application to Slough Borough Council. No Article 4 direction is recorded for Slough Borough Council, but Colnbrook & Poyle's 1 conservation area still limit permitted development on those streets. We check your exact address before drawing.
On shallow trussed roofs typical of 1970s building, common across Colnbrook & Poyle, a rear dormer is usually the most efficient conversion and often permitted development. Where the roof is trussed-rafter roofs typical of 2000s building, a hip-to-gable followed by a rear dormer gains far more usable space but needs planning permission. Our survey confirms which your roof supports before we draw. Slough Borough Council is the decision-maker.
A householder planning application in Colnbrook & Poyle runs to a statutory eight-week target, and a lawful development certificate to eight weeks as well, though validation can add time if the pack is incomplete. We submit validation-complete drawings and manage case-officer queries to keep the decision on track. Slough Borough Council is the decision-maker.
If your dormer is permitted development, a lawful development certificate from Slough Borough Council is council-stamped proof of that — worth having, because every buyer's solicitor will ask for it when you sell. We prepare and submit the certificate application with the same drawing pack. This applies to your Colnbrook & Poyle address specifically.
Every roof is different, so we quote each Colnbrook & Poyle project individually — a fixed, no-obligation price back within one working day. The quote covers the full drawing pack with free revisions until Slough Borough Council approves, and we tell you upfront whether your loft qualifies as permitted development. Call 020 7864 7245 to start.
Answer five quick questions and get a free planning score for your exact address — instantly. Then, if you want the full picture, unlock the detailed analysis: your council's live approval rates, local precedents, constraints on your street and a step-by-step route to permission.
Same fixed quotes, same fast drawings — wherever your project is.