Mansard drawings for Merton terraces — the rebuilt roof with a steep, near-vertical rear slope that adds a full storey of loft, drawn to Merton Council's roofline and streetscape rules, delivered in days and revised free until your decision, with a free approval-odds check first.
Merton 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 wooded, low-density character of Wimbledon Village and the Common caps bulk and roof enlargement on many plots, which is where a policy-literate drawing pack earns its keep. Its dominant Victorian (1837–1901), Edwardian (1901–1910) and interwar (1918–1939) housing stock sets the design brief on most streets.
The permitted-development ceilings are fixed: 40m³ of new roof volume for a terraced loft and 50m³ for a semi or detached house under Class B, plus a 3m single-storey rear extension on a terrace or 4m on a detached house under Class A. Merton carries at least one Article 4 direction, and conservation areas including Wimbledon Village, John Innes (Merton Park) and Mitcham Cricket Green remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Merton is determined against an 8-week statutory target.
Wimbledon (the leafy Village above Edwardian and Victorian streets), Merton Park (the John Innes estate of Arts and Crafts and Edwardian houses), Mitcham (interwar housing wrapped around the historic cricket green), Raynes Park (grids of Edwardian terraces west of the line), Colliers Wood (compact Victorian terraces along the Wandle) and Morden (1930s semi-detached suburbia and the St Helier fringe) — these are the Merton pockets our drawings cover most. Heritage designations here include Wimbledon Village, John Innes (Merton Park), Mitcham Cricket Green, Cottenham Park and Wimbledon West. Merton Council weighs each proposal against Merton Local Plan and the council's Design SPD, where the John Innes estate's Arts and Crafts detailing is protected in fine grain, down to porches, gates and boundary walls. Pockets of Wimbledon and Colliers Wood hold converted Victorian flats and maisonettes, which carry no householder permitted-development rights of their own.. On roofs the borough is pitched and gabled roofs on the terraces and villas and hipped roofs on the interwar semis, over Victorian and Edwardian terraces, detached Wimbledon villas and interwar semi-detached houses.
The mansard is the maximum-volume loft, and Merton's stock is where it belongs — the borough runs to Victorian and Edwardian terraces, detached Wimbledon villas and interwar semi-detached houses, 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. Merton Council assesses it against Merton Local Plan and the council's Design 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. The wooded, low-density character of Wimbledon Village and the Common caps bulk and roof enlargement on many plots, and on a roof this prominent that is the argument that has to be won on the page.
Much of Merton's terraced stock is designated — Wimbledon Village, John Innes (Merton Park), Mitcham Cricket Green, Cottenham Park and Wimbledon West among the areas — and there a mansard is judged on whether it restores or respects the historic roofline. Merton has withdrawn permitted-development rights on parts of the John Innes and Wimbledon Village conservation areas through Article 4 directions, so alterations that would be automatic elsewhere need a householder application here. Some terraces already have a consistent mansard line an addition can follow; others do not, and we establish which before drawing.
A mansard in Merton always needs a full application to Merton 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 Merton Council's officers check first — and submit a validation-complete householder application.
Below is Merton Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Merton consents the large majority of householder schemes, yet the leafy Wimbledon conservation areas and the uniform villa streets set close limits on how far roofs and side additions can go. 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.
Tell us about your project and get a fixed, no-obligation quote back within one working day. If you don't need planning permission at all, we'll tell you that too — for free.
Across Wimbledon, Merton Park and Mitcham, 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 victorian and edwardian terraces, this is the single biggest volume the roof can give — close to a full floor.
The John Innes estate's Arts and Crafts detailing is protected in fine grain, down to porches, gates and boundary walls. 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 Merton 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 Merton mansards come up most often:
Mansard loft drawings for Wimbledon's the leafy Village above Edwardian and Victorian streets — roofline-matched, slate-detailed and drawn to Merton Council's guidance.
Mansard loft drawings for Merton Park's the John Innes estate of Arts and Crafts and Edwardian houses — roofline-matched, slate-detailed and drawn to Merton Council's guidance.
Mansard loft drawings for Mitcham's interwar housing wrapped around the historic cricket green — roofline-matched, slate-detailed and drawn to Merton Council's guidance.
Mansard loft drawings for Raynes Park's grids of Edwardian terraces west of the line — roofline-matched, slate-detailed and drawn to Merton Council's guidance.
Mansard loft drawings for Colliers Wood's compact Victorian terraces along the Wandle — roofline-matched, slate-detailed and drawn to Merton Council's guidance.
Mansard loft drawings for Morden's 1930s semi-detached suburbia and the St Helier fringe — roofline-matched, slate-detailed and drawn to Merton 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 Merton.
| Loft type | Planning route | Space gained | What Merton 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 Wimbledon Village and John Innes (Merton Park), a mansard is judged on how it sits within the protected roofline of the terrace.
A fixed process built around how Merton Council validates and decides mansard applications — most drawings are submission-ready within seven days of survey.
Send us your Merton 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 Merton 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 Merton 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 Merton 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 Merton Council on every street, designated or not. On a terrace in a conservation area such as Wimbledon Village and John Innes (Merton Park) 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. Merton'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. Merton 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 Merton, a mansard is chosen when a dormer or hip-to-gable will not give enough room. Merton 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, Merton 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 Merton 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 Merton 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 Merton Council approves, and we confirm the roofline case at the outset. Call 020 7864 7245 to start.
Answer five quick questions and get a free planning score for your exact address — instantly. Then, if you want the full picture, unlock the detailed analysis: your council's live approval rates, local precedents, constraints on your street and a step-by-step route to permission.
Same fixed quotes, same fast drawings — wherever your project is.