Mansard drawings for Southwark terraces — the rebuilt roof with a steep, near-vertical rear slope that adds a full storey of loft, drawn to Southwark Council's roofline and streetscape rules, delivered in days and revised free until your decision, with a free approval-odds check first.
Southwark Council granted 89% of the householder planning decisions it made in its latest published year — 2 points above the 87% England-wide householder average. Mansards and roof extensions on terraces are assessed against the established roofline and the conservation-area appraisal, which is where a policy-literate drawing pack earns its keep. Its dominant Georgian (1714–1837), Victorian (1837–1901) 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. Southwark carries at least one Article 4 direction, and conservation areas including Camberwell Grove, Dulwich Village and Bermondsey Street remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Southwark is determined against an 8-week statutory target.
Camberwell (Georgian and Victorian terraces around Camberwell Grove), Dulwich (villas and the Dulwich Village conservation area under the Dulwich Estate), Bermondsey (warehouse conversions and terraces off Bermondsey Street), Peckham (Victorian terraces including the Holly Grove enclave), Nunhead (modest Victorian terraces near Nunhead Green and the cemetery) and Walworth (dense Georgian and Victorian terraces threaded through large estates) — these are the Southwark pockets our drawings cover most. Heritage designations here include Camberwell Grove, Dulwich Village, Bermondsey Street, Holly Grove and Nunhead Green. Southwark Council weighs each proposal against the Southwark Plan and the borough's Residential Design Standards SPD, where the borough runs detailed basement and residential design standards on top of the usual tests. Camberwell, Peckham and the warehouse quarters around Bermondsey are heavily subdivided into flats, none of which hold householder permitted-development rights.. On roofs the borough is butterfly and parapet roofs on the terraces and flat and pitched roofs on the former warehouses, over Georgian and Victorian terraces, former warehouse and industrial conversions and Dulwich villas and postwar estates.
The mansard is the maximum-volume loft, and Southwark's stock is where it belongs — the borough runs to Georgian and Victorian terraces, former warehouse and industrial conversions and Dulwich villas and postwar estates, and on a period terrace a mansard rebuilds the roof at roughly seventy degrees to create almost a full new floor rather than the part-height room a dormer returns. Southwark Council assesses it against the Southwark Plan and the borough's Residential Design Standards SPD, and because the whole roof changes shape the test is the street: whether the new profile continues the terrace or breaks it.
That is what the drawings have to settle. We set the mansard behind the original parapet or eaves, hold it to the ridge height of neighbouring mansards where the terrace already has them, and detail the slate face, the dormer windows within it and the party walls to both sides so the addition reads as part of the row. Mansards and roof extensions on terraces are assessed against the established roofline and the conservation-area appraisal, and on a roof this prominent that is the argument that has to be won on the page.
Much of Southwark's terraced stock is designated — Camberwell Grove, Dulwich Village, Bermondsey Street, Holly Grove and Nunhead Green among the areas — and there a mansard is judged on whether it restores or respects the historic roofline. Southwark carries numerous Article 4 directions across conservation areas such as Camberwell Grove and Bermondsey Street, while the Dulwich Estate's scheme of management adds a separate layer of consent in Dulwich. Some terraces already have a consistent mansard line an addition can follow; others do not, and we establish which before drawing.
A mansard in Southwark always needs a full application to Southwark Council — rebuilding the roof puts it well outside permitted development. These are the points the council weighs:
We draw the new roof behind the parapet, the slope and ridge matched to the terrace, the slate face and dormer windows, and the party walls to both neighbours — the roofline and streetscape relationships Southwark Council's officers check first — and submit a validation-complete householder application.
Below is Southwark Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Southwark grants most householder applications, but heavy conservation-area coverage, its basement policies and the Dulwich Estate's scheme of management dictate what is achievable in many neighbourhoods. A mansard is decided on roofline and streetscape, so a scheme drawn to continue the terrace is cleared faster and refused less often than one that fights it.
Source: MHCLG planning application statistics (householder decisions, rolling year). Compare every borough on our London approval-rate league table.
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Across Camberwell, Dulwich and Bermondsey, the mansard that goes through is the one that disappears into the row: set behind the parapet, its ridge matched to neighbouring mansards, the front slope in natural slate with traditional dormer windows, and the whole storey reading as though the terrace was always that height. On the borough's georgian and victorian terraces, this is the single biggest volume the roof can give — close to a full floor.
The borough runs detailed basement and residential design standards on top of the usual tests. We follow any established mansard line on the terrace, keep the slope and materials traditional, and where a row has none yet, draw a design that could set the pattern rather than break it — the argument Southwark Council needs to grant on a roof this visible.
We draw mansard roofs on the period-terrace streets across the borough. A few of the neighbourhoods where Southwark mansards come up most often:
Mansard loft drawings for Camberwell's Georgian and Victorian terraces around Camberwell Grove — roofline-matched, slate-detailed and drawn to Southwark Council's guidance.
Mansard loft drawings for Dulwich's villas and the Dulwich Village conservation area under the Dulwich Estate — roofline-matched, slate-detailed and drawn to Southwark Council's guidance.
Mansard loft drawings for Bermondsey's warehouse conversions and terraces off Bermondsey Street — roofline-matched, slate-detailed and drawn to Southwark Council's guidance.
Mansard loft drawings for Peckham's Victorian terraces including the Holly Grove enclave — roofline-matched, slate-detailed and drawn to Southwark Council's guidance.
Mansard loft drawings for Nunhead's modest Victorian terraces near Nunhead Green and the cemetery — roofline-matched, slate-detailed and drawn to Southwark Council's guidance.
Mansard loft drawings for Walworth's dense Georgian and Victorian terraces threaded through large estates — roofline-matched, slate-detailed and drawn to Southwark Council's guidance.
A mansard wins the most space of any loft but asks the most of the planning case. This is how it compares in Southwark.
| Loft type | Planning route | Space gained | What Southwark Council checks |
|---|---|---|---|
| Mansard | Always a full application | Close to a full extra storey | Roofline, streetscape, terrace match |
| Rear dormer | Often permitted development | A room across the back slope | Volume and eaves set-back |
| Hip-to-gable | Full application | Full width where the roof is hipped | Balance with the paired neighbour |
| Rooflights only | Usually permitted development | Light and headroom, no new shape | Rooflights within the existing slope |
In conservation areas such as Camberwell Grove and Dulwich Village, a mansard is judged on how it sits within the protected roofline of the terrace.
A fixed process built around how Southwark Council validates and decides mansard applications — most drawings are submission-ready within seven days of survey.
Send us your Southwark postcode and terrace type. We confirm your conservation and Article 4 status, check whether the row already has a mansard line to follow, and score your odds against live Southwark Council decisions.
We measure the parapet, ridge and party walls, and the roofline of the neighbouring houses — the numbers the new slope, its height and the terrace match depend on.
Chartered designers develop the rebuilt roof to your brief, drawn to Southwark Council's roof-alteration and conservation guidance with the slope, slate face, dormers and party walls detailed on the page.
We submit the householder application, manage validation and case-officer queries, and revise the drawings free until Southwark Council issues its decision.
Always. A mansard rebuilds the roof into a steep rear slope with a flat top, and that wholesale change of roof shape is well outside permitted development — so it needs a full householder application to Southwark Council on every street, designated or not. On a terrace in a conservation area such as Camberwell Grove and Dulwich Village the roofline is protected, so the design is scrutinised more closely still.
It is a rebuilt roof with a steep, near-vertical rear slope and a small flat top, which creates almost a full extra storey inside — far more than a dormer returns. Southwark's period terraces are the classic mansard candidates, and where a row already carries mansards a new one that matches the line is the most likely of all lofts to be approved despite being the largest. Southwark Council is the decision-maker.
Because it reshapes the whole roof rather than adding a box to it. The steep slope pushes the walls out almost to vertical and the flat top lifts the ceiling, so the usable floor runs nearly the full footprint of the house at head height — close to a complete storey. That is why, in Southwark, a mansard is chosen when a dormer or hip-to-gable will not give enough room. Southwark Council is the decision-maker.
It can, but the case is harder. Where a terrace already has a consistent mansard line, matching it is straightforward; on an unbroken row, Southwark Council weighs whether your mansard would break the skyline or could set an acceptable pattern for the street. We draw the design to sit within the terrace and make that argument on the elevations rather than leave it to chance.
Almost certainly, on both sides. A mansard rebuilds the roof up to and across the party walls with the neighbours either side, so the Party Wall etc. Act applies to each and notice must be served before work starts — separately from Southwark Council's planning decision. We detail both party walls on the drawings and flag the notices early so surveyors can be appointed without holding up the build.
We price each Southwark mansard individually, because the terrace, the roofline match and the party-wall detailing vary street to street, and send a fixed, no-obligation quote within one working day. It covers the full drawing pack with free revisions until Southwark Council approves, and we confirm the roofline case at the outset. Call 020 7864 7245 to start.
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