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Annexe and granny flat plans in East Southsea — self-contained accommodation ancillary to a family home
East Southsea · Annexe & Granny Flat Drawings

Annexe and granny flat plans in East Southsea

Annexe and granny-flat drawings for East Southsea homes — designed to stay ancillary to the main house rather than become a separate dwelling, drawn to Portsmouth City Council's policies, delivered in days and revised free until your decision.

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What the data says about planning in East Southsea

Portsmouth City Council granted 88% of the householder planning decisions it made in its latest published year — 1 point above the 87% England-wide householder average. The tightly repeating terrace rhythm means roof and rear additions are read against a long, uniform street frontage, which is where a policy-literate drawing pack earns its keep. Its dominant Victorian (1837–1901) and Edwardian (1901–1910) 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 Portsmouth City Council needs a full application. East Southsea carries at least one Article 4 direction, and conservation areas including East Southsea, The Terraces and Rochester Road remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in East Southsea is determined against an 8-week statutory target.

Rochester Road (late-Victorian and Edwardian brick terraces with many original features), Highland Terrace (nineteen mid-Victorian terraced houses with long front gardens), Festing Road (Edwardian terraces running down toward the seafront), Devonshire Avenue (grid of bay-fronted Victorian terraces), Waverley Road (wider Victorian houses near Canoe Lake) and Albert Road (east) (Victorian terraces behind the eastern shopping parade) — these are the East Southsea pockets our drawings cover most. Heritage designations here include East Southsea, The Terraces, Rochester Road and Highland Terrace. Portsmouth City Council weighs each proposal against the Portsmouth Local Plan and the council's Houses in Multiple Occupation SPD, where original brick detailing, sash windows and front-garden walls are the character that alterations must respect in the conservation areas. Many East Southsea terraces have been converted to flats and bedsits, which sit outside householder permitted-development rights.. On roofs the borough is pitched slate roofs on the brick terraces and valley and butterfly roofs behind parapet frontages, over late-Victorian and Edwardian brick terraces, mid-Victorian terraces with long front gardens and converted flats.

Ancillary or separate dwelling — the East Southsea test

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. Portsmouth 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.

East Southsea is largely late-Victorian and Edwardian brick terraces, mid-Victorian terraces with long front gardens and converted flats, 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 East Southsea's conservation areas — including East Southsea and The Terraces — 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. The city-wide Article 4 direction applies here too, removing permitted-development rights for small HMO conversions, so the late-Victorian brick terraces of Rochester Road and its neighbours need a planning application before a family house becomes a shared house.

Annexe accommodation designed for a East Southsea property

When does an annexe need planning permission in East Southsea?

An annexe almost always needs an application to Portsmouth City Council. Expect one where any of these apply:

  • The accommodation includes sleeping space, so it is not incidental under Class E
  • There is a separate entrance from the street rather than through the shared garden
  • The garden would be divided so each part serves one unit
  • The annexe has its own kitchen, utilities and postal address
  • It would be let, sold or occupied by someone unconnected to the main household
  • The property is on designated land such as East Southsea and The Terraces, where outbuilding rights are curtailed
  • An Article 4 direction applies to your street, removing the relevant permitted-development right

East Southsea annexe decisions — live from council data

Below is Portsmouth City Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Portsmouth approves the large majority of householder applications in East Southsea, with refusals turning on uniform terrace character, front-garden loss and the concentration of shared houses. 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.

89%householder applications approved in Portsmouth
87%national average — Portsmouth is 2 points above the national average

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What annexes get approved across East Southsea

Across Rochester Road, Highland Terrace and Festing Road, 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 late-victorian and edwardian brick terraces, 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.

The tightly repeating terrace rhythm means roof and rear additions are read against a long, uniform street frontage. Where Portsmouth 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.

Annexe drawing pack prepared for a East Southsea application

Annexe and granny flat drawings across East Southsea

We draw annexes across East Southsea. A few of the areas where multigenerational schemes come up most often:

Rochester Road

Annexe and granny-flat drawings for Rochester Road — late-Victorian and Edwardian brick terraces with many original features — planned to stay ancillary and drawn to Portsmouth City Council's policies.

Highland Terrace

Annexe and granny-flat drawings for Highland Terrace — nineteen mid-Victorian terraced houses with long front gardens — planned to stay ancillary and drawn to Portsmouth City Council's policies.

Festing Road

Annexe and granny-flat drawings for Festing Road — Edwardian terraces running down toward the seafront — planned to stay ancillary and drawn to Portsmouth City Council's policies.

Devonshire Avenue

Annexe and granny-flat drawings for Devonshire Avenue — grid of bay-fronted Victorian terraces — planned to stay ancillary and drawn to Portsmouth City Council's policies.

Waverley Road

Annexe and granny-flat drawings for Waverley Road — wider Victorian houses near Canoe Lake — planned to stay ancillary and drawn to Portsmouth City Council's policies.

Albert Road (east)

Annexe and granny-flat drawings for Albert Road (east) — Victorian terraces behind the eastern shopping parade — planned to stay ancillary and drawn to Portsmouth City Council's policies.

Annexe, outbuilding or new dwelling in East Southsea?

Three similar buildings, three different consents. This is what separates them.

What you buildPlanning statusKey testWhat Portsmouth City Council checks
Garden room, no sleeping spaceOften Class E permitted developmentIncidental to the houseHeight, footprint, boundary position
Annexe used by the householdFull application, usually with a tie conditionAncillary useShared garden and access, layout
Self-contained unit, own accessNew dwelling — full applicationSeparate planning unitPolicy on new homes, amenity, parking
Converted garage or ground floorOften permitted, use still assessedWhether use changesIndependence of the accommodation
Annexe on designated landFull applicationDesignationCharacter 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.

Four steps to an approved East Southsea annexe

A fixed process built around how Portsmouth City Council tests the use question as well as the design.

  1. 1

    Free approval check

    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 East Southsea.

  2. 2

    Measured survey

    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.

  3. 3

    Annexe design & drawings

    Chartered designers develop the annexe to your brief, with the layout, access and garden relationship arranged to support the ancillary case under Portsmouth City Council's policies.

  4. 4

    Submission & follow-through

    We submit the application with a supporting statement on use, manage validation and case-officer queries, and revise free until Portsmouth City Council decides.

Frequently asked questions

Do I need planning permission for an annexe in East Southsea?

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 East Southsea we prepare a full application to Portsmouth City Council and make the ancillary case explicitly rather than hoping it is not asked.

What makes an annexe ancillary rather than a separate dwelling in East Southsea?

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. Portsmouth 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 East Southsea address specifically.

Can I build a granny flat in the garden in East Southsea?

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 East Southsea, particularly near designated areas such as East Southsea and The Terraces. Portsmouth City Council is the decision-maker.

Will Portsmouth City Council attach conditions to an annexe permission?

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 East Southsea address specifically. Portsmouth City Council is the decision-maker.

Does an annexe need building regulations approval in East Southsea?

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 East Southsea address specifically. Portsmouth City Council is the decision-maker.

How long does an annexe application take in East Southsea?

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 East Southsea address specifically. Portsmouth City Council is the decision-maker.

How much do annexe plans in East Southsea cost?

We quote each East Southsea 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 Portsmouth City Council approves. Call 020 7864 7245 to start.

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