Back-of-house extension drawings for Bevois homes — the glazed kitchen-diner across the rear, drawn to Southampton City Council's depth and daylight limits, delivered in days and revised free until your decision, with a free approval-odds check first.
Southampton City Council granted 92% of the householder planning decisions it made in its latest published year — 5 points above the 87% England-wide householder average. HMO concentration limits are applied street by street, and proposals are refused where the balance of family housing is judged to be lost, which is where a policy-literate drawing pack earns its keep. Its dominant Georgian (1714–1837) and Victorian (1837–1901) 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 Southampton City Council needs a full application. Bevois carries at least one Article 4 direction, and conservation areas including Carlton Crescent and Cranbury Place remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Bevois is determined against an 8-week statutory target.
Bevois Mount (Victorian terraces on the slope above the Inner Avenue, heavily converted), Carlton Crescent (Southampton's finest Regency crescent under strict conservation control), Cranbury Place (early-Victorian villas and terraces in a designated conservation area), Inner Avenue (dense Victorian terraces along the main student corridor), Nicholstown (tightly packed Victorian terraces near St Mary's) and Newtown (mixed Victorian terraces with strong conversion pressure) — these are the Bevois pockets our drawings cover most. Heritage designations here include Carlton Crescent and Cranbury Place. Southampton City Council weighs each proposal against the Southampton City Local Plan / Core Strategy, where the Regency proportions and rendered frontages of Carlton Crescent are policed closely, pushing additions to the rear. A very large share of Bevois's terraces are split into flats and HMOs, so householder permitted-development rights rarely apply.. On roofs the borough is parapet and pitched slate roofs on the Regency terraces and pitched roofs with rear slopes on the Victorian rows, over Regency and early-Victorian terraces around Carlton Crescent and Cranbury Place, later Victorian bay-fronted terraces off the Inner Avenue and much of the terraced stock converted to flats and HMOs.
The rear extension is the workhorse of Bevois home improvement — it is how a dark back kitchen becomes an open family room facing the garden. Because the borough is built largely from Regency and early-Victorian terraces around Carlton Crescent and Cranbury Place, later Victorian bay-fronted terraces off the Inner Avenue and much of the terraced stock converted to flats and HMOs, most back walls sit close to a neighbour on at least one side, and that proximity, not the design, is what Southampton City Council scrutinises. The council reads the proposal against the Southampton City Local Plan / Core Strategy, 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. HMO concentration limits are applied street by street, and proposals are refused where the balance of family housing is judged to be lost, so the rear elevation is composed around it rather than corrected after an objection.
Where the property sits in a conservation area — Carlton Crescent and Cranbury Place among Bevois's — the larger-home extension route is switched off and even a modest rear addition needs consent. Bevois covers some of Southampton's most intense student and HMO streets, and the city-wide HMO Article 4 direction adopted in March 2012 removes the permitted-development right to change a Class C3 house to a small Class C4 HMO, so conversions here need planning permission. We confirm the designation before the survey.
Many single-storey rear extensions in Bevois are permitted development and need no application. You will normally need to apply to Southampton City 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 Southampton City 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 Southampton City Council's real householder decision record, taken from official planning statistics and refreshed as new data lands. Southampton grants around 92% of applications, yet in Bevois the management of HMO concentration is the dominant factor deciding conversion schemes. 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 Bevois Mount, Carlton Crescent and Cranbury Place, 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 regency and early-victorian terraces around carlton crescent and cranbury place, 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 Regency proportions and rendered frontages of Carlton Crescent are policed closely, pushing additions to the rear. We keep the extension inside the daylight splays, set any glazed roof below the first-floor cill, and retain the garden depth Southampton City 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 Bevois back-of-house projects come up most often:
Rear extension drawings for Bevois Mount's Victorian terraces on the slope above the Inner Avenue, heavily converted — depth-checked, daylight-tested and drawn to Southampton City Council's guidance.
Rear extension drawings for Carlton Crescent's Southampton's finest Regency crescent under strict conservation control — depth-checked, daylight-tested and drawn to Southampton City Council's guidance.
Rear extension drawings for Cranbury Place's early-Victorian villas and terraces in a designated conservation area — depth-checked, daylight-tested and drawn to Southampton City Council's guidance.
Rear extension drawings for Inner Avenue's dense Victorian terraces along the main student corridor — depth-checked, daylight-tested and drawn to Southampton City Council's guidance.
Rear extension drawings for Nicholstown's tightly packed Victorian terraces near St Mary's — depth-checked, daylight-tested and drawn to Southampton City Council's guidance.
Rear extension drawings for Newtown's mixed Victorian terraces with strong conversion pressure — depth-checked, daylight-tested and drawn to Southampton City Council's guidance.
How far you can extend at the back in Bevois depends on your house type and the route you take. This is how the options compare.
| Route | Depth allowed | Consent needed | What Southampton City 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 Carlton Crescent and Cranbury Place and Article 4 streets need a full application.
A fixed process built around how Southampton City Council validates and decides rear-extension applications — most drawings are submission-ready within seven days of survey.
Send us your Bevois 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 Southampton City 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 Southampton City 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 Southampton City 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 Bevois. You will need to involve Southampton City 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 Carlton Crescent and Cranbury Place, 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 Southampton City 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 Bevois's conservation areas.
It is the daylight test Southampton City 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 Bevois address specifically.
A two-storey rear extension almost always needs a full householder application to Southampton City 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 Bevois 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 Southampton City 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 Bevois address specifically.
We price each Bevois 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 Southampton City 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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