Annexe and granny-flat drawings for Longthorpe homes — designed to stay ancillary to the main house rather than become a separate dwelling, drawn to Peterborough City Council's policies, delivered in days and revised free until your decision.
Peterborough 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 setting of Thorpe Hall and the scheduled Longthorpe Tower constrains bulk and outlook on nearby plots, 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.
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. Longthorpe carries at least one Article 4 direction, and conservation areas including Longthorpe, City Centre and Castor remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Longthorpe is determined against an 8-week statutory target.
Longthorpe village (medieval church, Longthorpe Tower and cottages inside the conservation area), Thorpe Hall (the 17th-century hall and its protected parkland setting), Netherton (1970s New Town township housing to the north), Ravensthorpe (postwar and later suburban housing west of the centre), Thorpe Wood (wooded fringe and golf course edge with lower-density housing) and Castor & Ailsworth (stone-built conservation villages on the western approach) — these are the Longthorpe pockets our drawings cover most. Heritage designations here include Longthorpe, City Centre, Castor and Ailsworth. Peterborough City Council weighs each proposal against the Peterborough Local Plan (2019), where the Nene Park and river washland to the south bring flood-risk and landscape tests on the low-lying edge. On roofs the borough is hipped roofs on the interwar and postwar semis and stone and clay-tile roofs in the historic village core, over historic village core around Longthorpe Tower and Thorpe Hall, interwar and postwar detached and semi-detached houses and larger executive housing on the western fringe.
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. Peterborough 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.
Longthorpe is largely historic village core around Longthorpe Tower and Thorpe Hall, interwar and postwar detached and semi-detached houses and larger executive housing on the western fringe, 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 Longthorpe's conservation areas — including Longthorpe and City Centre — 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 Longthorpe conservation area, designated in 1969 and taking in the parkland setting of Thorpe Hall and the medieval Longthorpe Tower, removes permitted-development rights on its historic streets under the council's conservation controls.
An annexe almost always needs an application to Peterborough 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 Peterborough City Council has to test, rather than leaving the officer to assume the worst.
Below is Peterborough City Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Peterborough approves the large majority of householder applications, with Longthorpe's heritage assets and the Nene Park setting the main pressure points on the village edge. 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 Longthorpe village, Thorpe Hall and Netherton, 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 historic village core around longthorpe tower and thorpe hall, 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 setting of Thorpe Hall and the scheduled Longthorpe Tower constrains bulk and outlook on nearby plots. Where Peterborough 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 Longthorpe. A few of the areas where multigenerational schemes come up most often:
Annexe and granny-flat drawings for Longthorpe village — medieval church, Longthorpe Tower and cottages inside the conservation area — planned to stay ancillary and drawn to Peterborough City Council's policies.
Annexe and granny-flat drawings for Thorpe Hall — the 17th-century hall and its protected parkland setting — planned to stay ancillary and drawn to Peterborough City Council's policies.
Annexe and granny-flat drawings for Netherton — 1970s New Town township housing to the north — planned to stay ancillary and drawn to Peterborough City Council's policies.
Annexe and granny-flat drawings for Ravensthorpe — postwar and later suburban housing west of the centre — planned to stay ancillary and drawn to Peterborough City Council's policies.
Annexe and granny-flat drawings for Thorpe Wood — wooded fringe and golf course edge with lower-density housing — planned to stay ancillary and drawn to Peterborough City Council's policies.
Annexe and granny-flat drawings for Castor & Ailsworth — stone-built conservation villages on the western approach — planned to stay ancillary and drawn to Peterborough City Council's policies.
Three similar buildings, three different consents. This is what separates them.
| What you build | Planning status | Key test | What Peterborough 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 Peterborough 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 Longthorpe.
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 Peterborough City Council's policies.
We submit the application with a supporting statement on use, manage validation and case-officer queries, and revise free until Peterborough 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 Longthorpe we prepare a full application to Peterborough 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. Peterborough 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 Longthorpe 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 Longthorpe, particularly near designated areas such as Longthorpe and City Centre. Peterborough 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 Longthorpe address specifically. Peterborough 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 Longthorpe address specifically. Peterborough 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 Longthorpe address specifically. Peterborough City Council is the decision-maker.
We quote each Longthorpe 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 Peterborough City Council approves. Call 020 7864 7245 to start.
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