Annexe and granny-flat drawings for Bevois homes — designed to stay ancillary to the main house rather than become a separate dwelling, drawn to Southampton City Council's policies, delivered in days and revised free until your decision.
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.
Councils do not decide annexes on square metres. They decide whether, once built, the accommodation forms part of one planning unit with the main house or a second one beside it. Southampton City Council looks at whether the garden is shared or divided, whether the annexe has its own street access and address, whether the occupier could live there entirely independently, and whether the two households would function as one. That is the whole case, and it is made or lost on the layout.
Bevois is largely 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, which shapes the realistic options: converting part of the existing house, extending it, or building a detached unit in the garden. A detached annexe can sometimes sit under Class E as an outbuilding incidental to the enjoyment of the dwellinghouse — but sleeping accommodation is generally not "incidental", so a garden annexe with a bedroom usually needs its own permission rather than relying on outbuilding rights.
In Bevois's conservation areas — including Carlton Crescent and Cranbury Place — a garden building is also judged on its effect on the character of the area, which limits height and footprint before the use question is reached. 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.
An annexe almost always needs an application to Southampton City Council. Expect one where any of these apply:
We plan the annexe so its relationship to the main house is visible on the page — shared garden, connected access, a layout that reads as one household — and set out the case Southampton City Council has to test, rather than leaving the officer to assume the worst.
Below is Southampton City Council's real householder decision record, drawn 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. Annexe applications are decided on use as much as design, so the supporting case matters as much as the elevations.
Source: MHCLG planning application statistics (householder decisions, England, 1 April 2025 - 31 March 2026). Compare every borough on our London approval-rate league table.
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Across Bevois Mount, Carlton Crescent and Cranbury Place, the annexes that succeed keep one shared garden, take access past the main house rather than from the street, and are modest against the host building — single storey where the plot is overlooked, and set back from boundaries. On regency and early-victorian terraces around carlton crescent and cranbury place, converting an integral garage or a rear ground floor is often approved more readily than a detached garden unit, because the ancillary relationship is self-evident.
HMO concentration limits are applied street by street, and proposals are refused where the balance of family housing is judged to be lost. Where Southampton City Council grants permission, it commonly attaches a condition tying occupation of the annexe to the main dwelling. That condition is not a problem to be avoided — it is usually the mechanism that makes approval possible, and we draft the application on that basis rather than pretending the annexe is something it is not.
We draw annexes across Bevois. A few of the areas where multigenerational schemes come up most often:
Annexe and granny-flat drawings for Bevois Mount — Victorian terraces on the slope above the Inner Avenue, heavily converted — planned to stay ancillary and drawn to Southampton City Council's policies.
Annexe and granny-flat drawings for Carlton Crescent — Southampton's finest Regency crescent under strict conservation control — planned to stay ancillary and drawn to Southampton City Council's policies.
Annexe and granny-flat drawings for Cranbury Place — early-Victorian villas and terraces in a designated conservation area — planned to stay ancillary and drawn to Southampton City Council's policies.
Annexe and granny-flat drawings for Inner Avenue — dense Victorian terraces along the main student corridor — planned to stay ancillary and drawn to Southampton City Council's policies.
Annexe and granny-flat drawings for Nicholstown — tightly packed Victorian terraces near St Mary's — planned to stay ancillary and drawn to Southampton City Council's policies.
Annexe and granny-flat drawings for Newtown — mixed Victorian terraces with strong conversion pressure — planned to stay ancillary and drawn to Southampton City Council's policies.
Three similar buildings, three different consents. This is what separates them.
| What you build | Planning status | Key test | What Southampton City Council checks |
|---|---|---|---|
| Garden room, no sleeping space | Often Class E permitted development | Incidental to the house | Height, footprint, boundary position |
| Annexe used by the household | Full application, usually with a tie condition | Ancillary use | Shared garden and access, layout |
| Self-contained unit, own access | New dwelling — full application | Separate planning unit | Policy on new homes, amenity, parking |
| Converted garage or ground floor | Often permitted, use still assessed | Whether use changes | Independence of the accommodation |
| Annexe on designated land | Full application | Designation | Character and appearance |
The ancillary/separate-dwelling distinction comes from section 55 of the Town and Country Planning Act 1990; outbuilding limits from the GPDO 2015, Schedule 2, Part 1, Class E.
A fixed process built around how Southampton City Council tests the use question as well as the design.
Tell us who the annexe is for and where it would sit on the plot. We confirm designation status and tell you honestly whether the scheme reads as ancillary or as a separate dwelling in Bevois.
We measure the plot, the existing house and the access route, so the shared-garden and shared-access case can be drawn rather than asserted.
Chartered designers develop the annexe to your brief, with the layout, access and garden relationship arranged to support the ancillary case under Southampton City Council's policies.
We submit the application with a supporting statement on use, manage validation and case-officer queries, and revise free until Southampton City Council decides.
Almost always. Sleeping accommodation is generally not "incidental" to the enjoyment of a house, so it falls outside the outbuilding permitted-development right, and any annexe that could function independently raises a change-of-use question under section 55. In Bevois we prepare a full application to Southampton City Council and make the ancillary case explicitly rather than hoping it is not asked.
A shared garden rather than a divided one, access through the main property rather than a separate street entrance, occupation by a member of the same household, and a physical and functional relationship with the main house. Southampton City Council weighs those together — no single feature decides it, but a separate front door and a fenced-off garden together usually settle it against you. This applies to your Bevois address specifically.
Yes, subject to permission. A detached garden annexe is assessed on its scale against the plot, its effect on neighbours and the character of the area, and then on the use question. Keeping it single storey, set in from boundaries and served off the shared garden gives it the best prospect in Bevois, particularly near designated areas such as Carlton Crescent and Cranbury Place. Southampton City Council is the decision-maker.
Commonly, yes — a condition tying occupation of the annexe to the main dwelling, so it cannot be sold or let separately. That is normally what makes approval possible, because it removes the concern that a new independent home is being created without going through housing policy. The condition runs with the land, so it matters at resale, and we explain the implications before you commit. This applies to your Bevois address specifically. Southampton City Council is the decision-maker.
Yes. A new annexe is new habitable accommodation, so structure, fire escape, insulation and ventilation all apply, and a detached annexe close to a boundary raises fire-spread requirements as well. Planning and building control are separate consents with separate submissions — we prepare both so the approved design is the one that can actually be built. This applies to your Bevois address specifically. Southampton City Council is the decision-maker.
A householder application runs to an eight-week statutory target; where the council treats the annexe as creating a new unit it becomes a minor application with a thirteen-week target instead. Which route applies depends on how the use is characterised, which is precisely why the ancillary case is worth making properly at the outset. This applies to your Bevois address specifically. Southampton City Council is the decision-maker.
We quote each Bevois annexe individually, because plot, access and whether you are converting or building new all change the work, and send a fixed, no-obligation quote within one working day. It covers the full drawing pack and supporting statement, with free revisions until Southampton City Council approves. Call 020 7864 7245 to start.
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