Back-of-house extension drawings for Langley St Mary's homes — the glazed kitchen-diner across the rear, drawn to Slough Borough Council's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check 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. Langley St Mary's contains St Bernard's School, St Mary's Church, Langley conservation areas (St Mary's Church, Langley designated 1977), so materials, fenestration and roof form are assessed against the appraisal, which is where a policy-literate drawing pack earns its keep. Its dominant interwar (1918–1939) 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. In conservation areas such as St Bernard's School and St Mary's Church, Langley those rights are removed, so we confirm your exact address before a line is drawn. A validated householder application in Langley St Mary's is determined against an 8-week statutory target.
St Bernard's School (designated conservation area) and St Mary's Church, Langley (conservation area designated in 1977) — these are the Langley St Mary's pockets our drawings cover most. Heritage designations here include St Bernard's School and St Mary's Church, Langley. Slough Borough Council weighs each proposal against the adopted Slough local plan and Slough Borough Council's design guidance for householder work, where the 2,090 homes here are 36% 1955-1964, 10% 1930-1939, 9% 1965-1972, which is what sets the realistic roof and rear-projection options. On roofs the borough is shallow gabled roofs typical of that period's building and hipped roofs with shallow pitches typical of 1930s building, over late-1950s and early-1960s houses (36% of 2,090 homes), 1930s semi-detached and detached houses (10%) and late-1960s and early-1970s houses (9%).
What is permitted in Langley St Mary's turns on designation first, so that is where we start: St Bernard's School (designated conservation area) and St Mary's Church, Langley (conservation area designated in 1977). 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.
No Article 4 direction is recorded for Slough Borough Council, but Langley St Mary's's 2 conservation areas still limit permitted development on those streets.
On stock, Langley St Mary's is late-1950s and early-1960s houses (36% of 2,090 homes), 1930s semi-detached and detached houses (10%) and late-1960s and early-1970s houses (9%) — which is why shallow gabled roofs typical of that period's building and hipped roofs with shallow pitches typical of 1930s 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. We draw to that record rather than to a national average.
The full build-period split for Langley St Mary's runs pre-1900 1% (30 homes), 1900-1918 1% (20 homes), 1919-1929 2% (50 homes), 1930-1939 10% (210 homes), 1945-1954 0% (10 homes), 1955-1964 36% (760 homes), 1965-1972 9% (190 homes), 1973-1982 7% (140 homes), 1983-1992 3% (70 homes), 1993-1999 0% (10 homes) and 2000-2008 8% (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.
Slough Borough Council also decides for Colnbrook & Poyle, so a decision in Langley 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.
Published figures for Langley St Mary's 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 | Langley St Mary's |
|---|---|
| Dwellings recorded | 2,090 |
| Built pre-1900 | 30 (1%) |
| Built 1900-1918 | 20 (1%) |
| Built 1919-1929 | 50 (2%) |
| Built 1930-1939 | 210 (10%) |
| Built 1945-1954 | 10 (0%) |
| Built 1955-1964 | 760 (36%) |
| Built 1965-1972 | 190 (9%) |
| Built 1973-1982 | 140 (7%) |
| Built 1983-1992 | 70 (3%) |
| Built 1993-1999 | 10 (0%) |
| Built 2000-2008 | 160 (8%) |
| Built before 1919 | 2% |
| Built 1919–1939 | 12% |
| Built 1945–2008 | 64% |
| Conservation areas in Langley St Mary's | 2 (St Bernard's School, St Mary's Church, Langley) |
| 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.
The rear extension is the workhorse of Langley St Mary's home improvement — it is how a dark back kitchen becomes an open family room facing the garden. Because the borough is built largely from late-1950s and early-1960s houses (36% of 2,090 homes), 1930s semi-detached and detached houses (10%) and late-1960s and early-1970s houses (9%), most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what Slough Borough Council scrutinises. The council reads the proposal against the adopted Slough local plan and Slough Borough Council's design guidance for householder work, and the first line an officer draws is the 45-degree splay from the neighbour's nearest window.
So the drawings live or die on geometry. We set the depth against the exact permitted-development figure, hold the eaves and the flat-roof or lantern build-up under the 4-metre height ceiling, and show the projection tested against both the 45-degree plan angle and the 25-degree section angle to the neighbouring windows. Langley St Mary's contains St Bernard's School, St Mary's Church, Langley conservation areas (St Mary's Church, Langley designated 1977), so materials, fenestration and roof form are assessed against the appraisal, so the rear elevation is composed around it rather than corrected after an objection.
Where the property sits in a conservation area — St Bernard's School and St Mary's Church, Langley among Langley St Mary's's — the larger-home extension route is switched off and even a modest rear addition needs consent. No Article 4 direction is recorded for Slough Borough Council, but Langley St Mary's's 2 conservation areas still limit permitted development on those streets. We confirm the designation before the survey.
Many single-storey rear extensions in Langley St Mary's are permitted development and need no application. You will normally need to apply to Slough Borough Council, or use the larger-home prior-approval route, if any of these apply:
We draw the depth, the roof build-up and the daylight splays to each neighbour on the page — the tests Slough Borough Council's officers apply first — and submit a validation-complete pack, whether that is a lawful development certificate, a larger-home prior-approval notice or a full householder application.
Below is Slough Borough Council's real householder decision record, taken from official planning statistics and refreshed as new data lands. Slough Borough Council granted 82% of its householder applications in the year to 31 March 2026, and St Bernard's School shapes what is approved here. Rear extensions turn most often on neighbour daylight and depth, so a drawing pack that proves those tests upfront is decided 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 St Bernard's School and St Mary's Church, Langley, the approved rear extension is typically a single-storey glazed box within the depth limit, roofed either flat with a lantern or in a shallow mono-pitch, and finished in brick or render to match the host wall. On the borough's late-1950s and early-1960s houses (36% of 2,090 homes), keeping the projection to the permitted-development figure often avoids an application entirely; where owners want the full 6 metres, the larger-home route succeeds when the neighbour-consultation period passes without a sustained objection.
The 2,090 homes here are 36% 1955-1964, 10% 1930-1939, 9% 1965-1972, which is what sets the realistic roof and rear-projection options. We keep the extension inside the daylight splays, set any glazed roof below the first-floor cill, and retain the garden depth Slough Borough Council expects — so the back elevation answers the amenity case before a neighbour can lodge one. Two-storey rear extensions we draw with the 7-metre boundary gap and privacy screening resolved on the plan.
We draw rear extensions on every street in the borough. A few of the neighbourhoods where Langley St Mary's back-of-house projects come up most often:
Rear extension drawings for St Bernard's School's designated conservation area — depth-checked, daylight-tested and drawn to Slough Borough Council's guidance.
Rear extension drawings for St Mary's Church, Langley's conservation area designated in 1977 — depth-checked, daylight-tested and drawn to Slough Borough Council's guidance.
How far you can extend at the back in Langley St Mary's depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What Slough Borough Council checks |
|---|---|---|---|
| Standard permitted development | 3m terrace/semi · 4m detached | Lawful development certificate (optional) | Depth, 4m height, materials |
| Larger-home prior approval | 6m terrace/semi · 8m detached | Prior-approval notice + neighbour consultation | Neighbour objections on amenity |
| Full householder application | Beyond the above, or two-storey | Full planning permission | Daylight (45°/25°), bulk, garden retained |
| Conservation area | Case by case | Full planning permission | Character, roof form, boundary treatment |
The larger-home route is switched off on designated land — conservation areas such as St Bernard's School and St Mary's Church, Langley and Article 4 streets need a full application.
A fixed process built around how Slough Borough Council validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your Langley St Mary's postcode and house type. We confirm your conservation and Article 4 status, how much rear-extension depth you have under permitted development, and score your odds against live Slough Borough Council decisions.
We measure the original rear wall, floor and eaves levels, side and rear boundary distances and the neighbours' window positions — the numbers the depth limit and daylight splays depend on.
Chartered designers develop the single or two-storey rear extension to your brief, drawn inside the permitted-development limits or to Slough Borough Council's extension design guidance, with the daylight angles shown.
We submit the certificate, prior-approval notice or application, handle validation and case-officer queries, and revise the drawings free until Slough Borough Council issues its decision.
Often not. 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 Langley St Mary's. You will need to involve Slough Borough Council for anything deeper via the larger-home route, for two-storey rear extensions, and for any rear extension in a conservation area such as St Bernard's School and St Mary's Church, Langley, where those permitted-development rights fall away.
The larger-home extension scheme lets a single-storey rear extension reach 6 metres on a terrace or semi, or 8 metres on a detached house — double the standard allowance. It is not automatic: you submit a prior-approval notification to Slough Borough Council, neighbours are consulted, and if one objects on amenity grounds the council rules on it. It also does not apply on designated land such as Langley St Mary's's conservation areas.
It is the daylight test Slough Borough Council applies to protect neighbours. Drawn on plan, a line at 45 degrees from the midpoint of the neighbour's nearest ground-floor window should not be crossed by your extension; a companion 25-degree line is checked in section. If the projection breaches it, the extension is likely to be shortened or refused, so we test and prove it on the drawings before submission. This applies to your Langley St Mary's address specifically.
A two-storey rear extension almost always needs a full householder application to Slough Borough Council, as it sits outside permitted development on most homes. The council checks that it stays at least 7 metres from the rear boundary, does not overbear the neighbours and avoids new overlooking. We resolve the boundary gap, privacy and daylight on the plans so the application is decided on its merits. This applies to your Langley St Mary's address specifically.
Frequently, yes. If the rear extension involves work to a shared wall, building up to the boundary, or excavating foundations near a neighbour's structure, the Party Wall etc. Act applies and you must serve notice — this is separate from Slough Borough Council's planning decision. We flag it early and can prepare the drawings a party-wall surveyor needs alongside the planning set. This applies to your Langley St Mary's address specifically.
We price each Langley St Mary's rear extension on its own footprint and send a fixed, no-obligation quote within one working day. It covers the full drawing pack with free revisions until Slough Borough Council approves, and we confirm at the outset whether your extension is permitted development, needs prior approval, or a full application. Call 020 7864 7245 to begin.
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