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

Annexe and granny flat plans in Lewisham

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

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Lewisham householder planning by the numbers

Lewisham Council granted 90% of the householder planning decisions it made in its latest published year — 3 points above the 87% England-wide householder average. Policies resist the loss of family-sized houses, so conversions to flats face an added hurdle, which is where a policy-literate drawing pack earns its keep. Its dominant Georgian (1714–1837), Victorian (1837–1901) and Edwardian (1901–1910) housing stock sets the design brief on most streets.

Under Class B, a rear dormer stays permitted development up to 40m³ of added roof volume on a terrace or 50m³ on a semi-detached or detached house, while Class A allows a single-storey rear extension of 3m beyond the original rear wall on a terrace and 4m on a detached house before a full application is needed. Lewisham carries at least one Article 4 direction, and conservation areas including Blackheath, Telegraph Hill and Brockley remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Lewisham is determined against an 8-week statutory target.

Blackheath (grand villas and terraces on the Lewisham side of the heath), Brockley (long Victorian terraces within one of London's largest conservation areas), Telegraph Hill (hilly Victorian terraces framing the two parks), Deptford (Georgian survivals like Albury Street amid dense terraced streets), Forest Hill (Victorian villas and terraces stepping up the slopes) and Sydenham (Victorian terraces and semis toward the Crystal Palace ridge) — these are the Lewisham pockets our drawings cover most. Heritage designations here include Blackheath, Telegraph Hill, Brockley, Deptford High Street and Sydenham. Lewisham Council weighs each proposal against the Lewisham Local Plan and the borough's Alterations and Extensions SPD, where in the Brockley and Telegraph Hill conservation areas original slate roofs and front elevations are closely guarded. Brockley, Forest Hill and Deptford hold large numbers of houses long ago converted into flats and maisonettes, which carry no householder permitted-development rights.. On roofs the borough is London butterfly roofs on the Victorian terraces and gabled roofs on the villas, over Victorian terraces, Victorian and Edwardian villas and converted flats and maisonettes.

Ancillary or separate dwelling — the Lewisham 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. Lewisham 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.

Lewisham is largely Victorian terraces, Victorian and Edwardian villas and converted flats and maisonettes, 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 Lewisham's conservation areas — including Blackheath and Telegraph Hill — 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. Lewisham operates Article 4 directions in conservation areas such as Brockley alongside controls resisting the conversion of family houses into flats, so works that are permitted development elsewhere routinely need an application here.

Annexe accommodation designed for a Lewisham property

When does an annexe need planning permission in Lewisham?

An annexe almost always needs an application to Lewisham 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 Blackheath and Telegraph Hill, where outbuilding rights are curtailed
  • An Article 4 direction applies to your street, removing the relevant permitted-development right

Lewisham annexe decisions — live from council data

Below is Lewisham Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Lewisham grants the large majority of householder applications, though its policy shielding family houses from conversion and its Victorian conservation areas shape roof and rear works street by street. 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, rolling year). Compare every borough on our London approval-rate league table.

90%householder applications approved in Lewisham
87%national average — Lewisham is 3 points above the national average

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What annexes get approved across Lewisham

Across Blackheath, Brockley and Telegraph Hill, 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 victorian 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.

Policies resist the loss of family-sized houses, so conversions to flats face an added hurdle. Where Lewisham 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 Lewisham application

Annexe and granny flat drawings across Lewisham

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

Blackheath

Annexe and granny-flat drawings for Blackheath — grand villas and terraces on the Lewisham side of the heath — planned to stay ancillary and drawn to Lewisham Council's policies.

Brockley

Annexe and granny-flat drawings for Brockley — long Victorian terraces within one of London's largest conservation areas — planned to stay ancillary and drawn to Lewisham Council's policies.

Telegraph Hill

Annexe and granny-flat drawings for Telegraph Hill — hilly Victorian terraces framing the two parks — planned to stay ancillary and drawn to Lewisham Council's policies.

Deptford

Annexe and granny-flat drawings for Deptford — Georgian survivals like Albury Street amid dense terraced streets — planned to stay ancillary and drawn to Lewisham Council's policies.

Forest Hill

Annexe and granny-flat drawings for Forest Hill — Victorian villas and terraces stepping up the slopes — planned to stay ancillary and drawn to Lewisham Council's policies.

Sydenham

Annexe and granny-flat drawings for Sydenham — Victorian terraces and semis toward the Crystal Palace ridge — planned to stay ancillary and drawn to Lewisham Council's policies.

Annexe, outbuilding or new dwelling in Lewisham?

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

What you buildPlanning statusKey testWhat Lewisham 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 Lewisham annexe

A fixed process built around how Lewisham 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 Lewisham.

  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 Lewisham 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 Lewisham Council decides.

Frequently asked questions

Do I need planning permission for an annexe in Lewisham?

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 Lewisham we prepare a full application to Lewisham 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 Lewisham?

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. Lewisham 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.

Can I build a granny flat in the garden in Lewisham?

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 Lewisham, particularly near designated areas such as Blackheath and Telegraph Hill. Lewisham Council is the decision-maker.

Will Lewisham 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 Lewisham address specifically. Lewisham Council is the decision-maker.

Does an annexe need building regulations approval in Lewisham?

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 Lewisham address specifically. Lewisham Council is the decision-maker.

How long does an annexe application take in Lewisham?

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 Lewisham address specifically. Lewisham Council is the decision-maker.

How much do annexe plans in Lewisham cost?

We quote each Lewisham 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 Lewisham Council approves. Call 020 7864 7245 to start.

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