Dormer, hip-to-gable and mansard loft conversion drawings for Merton homes — prepared to Merton Council's design guidance, delivered in days and revised free until your decision lands, with a free approval-odds score 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.
Merton's roofs set the brief. The borough is built largely from Victorian and Edwardian terraces, detached Wimbledon villas and interwar semi-detached houses, and its lofts sit under pitched and gabled roofs on the terraces and villas and hipped roofs on the interwar semis — the geometry that decides whether a rear dormer, a hip-to-gable or a mansard gives you the headroom you want. Merton Council assesses loft proposals against Merton Local Plan and the council's Design SPD, and its case officers read each roof against the pair next door and the wider street before they read the plans.
That makes drawing quality decisive. We measure ridge and eaves heights, roof pitch and the existing stair, calculate the added volume against the permitted-development limits exactly, and show the workings on the drawings so Merton Council can verify them. The wooded, low-density character of Wimbledon Village and the Common caps bulk and roof enlargement on many plots, so we resolve it on the page rather than leave it for the case officer to raise.
Merton also carries protected streets — Wimbledon Village, John Innes (Merton Park), Mitcham Cricket Green, Cottenham Park and Wimbledon West among them. 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. We check your address against those designations before a line is drawn.
Many Merton loft conversions proceed without planning permission — a rear dormer within the permitted-development volume limits (40 cubic metres on a terrace, 50 on a semi or detached house) is usually lawful. You will normally need a full application to Merton Council if any of these apply:
We draw the roof line, the ridge height and the neighbour's daylight on the page — the relationships Merton Council's officers check first — and submit a validation-complete pack, whether that is a lawful development certificate or a full householder application.
Below is Merton Council's real householder decision record, pulled from official planning statistics and updated 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. Professionally prepared loft drawings anticipate those pressure points before submission, which is why complete, policy-literate packs are decided faster and refused less often than DIY applications.
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 recurring loft is the rear dormer — a box across the back roof slope that turns a cramped attic into a full-height double bedroom and en-suite. On pitched and gabled roofs on the terraces and villas, that is usually the most efficient use of the roof; where the stock is hipped roofs on the interwar semis, a hip-to-gable followed by a rear dormer unlocks far more space, though it needs a full application.
The John Innes estate's Arts and Crafts detailing is protected in fine grain, down to porches, gates and boundary walls. We draw the dormer inside the volume allowance, keep the flat-roof build-up below the ridge, and set the face back from the eaves as the rules require — so the pack answers Merton Council's questions before they are asked. Where permitted-development rights are exhausted or removed, we prepare a householder application composed to the borough's roof-alteration guidance instead.
We draw loft conversions on every street in the borough. A few of the neighbourhoods where Merton roofs come up most often:
Loft conversion drawings for Wimbledon's the leafy Village above Edwardian and Victorian streets — measured, volume-checked and drawn to Merton Council's guidance.
Loft conversion drawings for Merton Park's the John Innes estate of Arts and Crafts and Edwardian houses — measured, volume-checked and drawn to Merton Council's guidance.
Loft conversion drawings for Mitcham's interwar housing wrapped around the historic cricket green — measured, volume-checked and drawn to Merton Council's guidance.
Loft conversion drawings for Raynes Park's grids of Edwardian terraces west of the line — measured, volume-checked and drawn to Merton Council's guidance.
Loft conversion drawings for Colliers Wood's compact Victorian terraces along the Wandle — measured, volume-checked and drawn to Merton Council's guidance.
Loft conversion drawings for Morden's 1930s semi-detached suburbia and the St Helier fringe — measured, volume-checked and drawn to Merton Council's guidance.
The right loft in Merton depends on your roof. This is how the main types compare on planning route and the space they add.
| Loft type | Permitted development? | Space & headroom | What Merton Council checks |
|---|---|---|---|
| Rear dormer | Usually yes, within volume limits | Full-height double room at the back | Volume, set-back from eaves, ridge height |
| Hip-to-gable | No — full application | Extends the whole side of the roof | Roof bulk and the symmetry of the pair |
| Mansard | No — full application | Maximum floor area across the roof | Street character, especially in conservation areas |
| Rooflights only | Usually yes (Class C) | Light and headroom, no extra footprint | Whether rooflights sit within the existing slope |
Route depends on your street — conservation areas such as Wimbledon Village and John Innes (Merton Park) and Article 4 directions can remove permitted-development rights.
A fixed process built around how Merton Council validates and decides householder loft applications — most drawings are submission-ready within seven days of survey.
Tell us your Merton postcode and roof type. We confirm your conservation and Article 4 status, how much permitted-development volume you have left, and score your odds against live Merton Council decisions.
We measure ridge and eaves heights, roof pitch, joist levels and the existing stair — the numbers the volume calculation and head heights depend on.
Chartered designers develop the dormer, hip-to-gable or mansard to your brief, drawn inside the Class B limits or to Merton Council's roof-alteration guidance.
We submit the certificate or application, manage validation and case-officer queries, and revise the drawings free until Merton Council issues its decision.
Often not. A rear dormer within 40 cubic metres on a terrace, or 50 on a semi-detached or detached house, set back from the eaves and no higher than the ridge, is usually permitted development. In Merton the main exceptions are hip-to-gable conversions, dormers visible from the highway, and homes in conservation areas such as Wimbledon Village and John Innes (Merton Park) or on streets with an Article 4 direction. Merton Council is the decision-maker.
Generally no. In conservation areas including Wimbledon Village and John Innes (Merton Park), Class B permitted-development rights for lofts are removed, so a rear dormer that would be lawful elsewhere needs a full application to Merton Council. 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. We check your exact address before drawing.
On pitched and gabled roofs on the terraces and villas, common across Merton, a rear dormer is usually the most efficient conversion and often permitted development. Where the roof is hipped roofs on the interwar semis, a hip-to-gable followed by a rear dormer gains far more usable space but needs planning permission. Our survey confirms which your roof supports before we draw. Merton Council is the decision-maker.
A householder planning application in Merton runs to a statutory eight-week target, and a lawful development certificate to eight weeks as well, though validation can add time if the pack is incomplete. We submit validation-complete drawings and manage case-officer queries to keep the decision on track. Merton Council is the decision-maker.
If your dormer is permitted development, a lawful development certificate from Merton Council is council-stamped proof of that — worth having, because every buyer's solicitor will ask for it when you sell. We prepare and submit the certificate application with the same drawing pack.
Every roof is different, so we quote each Merton project individually — a fixed, no-obligation price back within one working day. The quote covers the full drawing pack with free revisions until Merton Council approves, and we tell you upfront whether your loft qualifies as permitted development. 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.