Mansard drawings for Barnet terraces — the rebuilt roof with a steep, near-vertical rear slope that adds a full storey of loft, drawn to Barnet Council's roofline and streetscape rules, delivered in days and revised free until your decision, with a free approval-odds check first.
Barnet Council granted 86% of the householder planning decisions it made in its latest published year — 1 point below the 87% England-wide householder average. Hampstead Garden Suburb schemes are assessed against the Suburb's own design code as well as council policy, which is where a policy-literate drawing pack earns its keep. Its dominant Edwardian (1901–1910), interwar (1918–1939) and postwar (1945–1970) housing stock sets the design brief on most streets.
Class A and Class B set the thresholds — a rear dormer to 40m³ on a terrace or 50m³ on a semi or detached, and a single-storey rear extension to 3m on a terrace or 4m on a detached house — beyond which Barnet Council needs a full application. Barnet carries at least one Article 4 direction, and conservation areas including Hampstead Garden Suburb, Mill Hill and Monken Hadley remove those rights outright, so we confirm your exact address before a line is drawn. A validated householder application in Barnet is determined against an 8-week statutory target.
Finchley (1930s semis around Church End), Golders Green (Edwardian and interwar houses near Hampstead Garden Suburb), Hendon (interwar semi-detached estates), Mill Hill (detached houses and the Mill Hill conservation area), Edgware (Metroland semis with hipped roofs) and Totteridge (large plots within the Green Belt and conservation area) — these are the Barnet pockets our drawings cover most. Heritage designations here include Hampstead Garden Suburb, Mill Hill, Monken Hadley, Totteridge and Finchley (Church End). Barnet Council weighs each proposal against Barnet Local Plan and the Residential Design Guidance SPD, where roof form and the symmetry of paired 1930s houses are decisive for lofts. On roofs the borough is hipped roofs on the Metroland semis and steep tiled roofs in the Garden Suburb, over 1930s semi-detached houses, Hampstead Garden Suburb cottages and houses and postwar and detached homes.
The mansard is the maximum-volume loft, and Barnet's stock is where it belongs — the borough runs to 1930s semi-detached houses, Hampstead Garden Suburb cottages and houses and postwar and detached homes, 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. Barnet Council assesses it against Barnet Local Plan and the Residential Design Guidance 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. Hampstead Garden Suburb schemes are assessed against the Suburb's own design code as well as council policy, and on a roof this prominent that is the argument that has to be won on the page.
Much of Barnet's terraced stock is designated — Hampstead Garden Suburb, Mill Hill, Monken Hadley, Totteridge and Finchley (Church End) among the areas — and there a mansard is judged on whether it restores or respects the historic roofline. Hampstead Garden Suburb is one of London's most tightly controlled conservation areas, with an Article 4 direction and its own Trust scheme of management — most external changes there need consent. Some terraces already have a consistent mansard line an addition can follow; others do not, and we establish which before drawing.
A mansard in Barnet always needs a full application to Barnet 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 Barnet Council's officers check first — and submit a validation-complete householder application.
Below is Barnet Council's real householder decision record, drawn from official planning statistics and refreshed as new data lands. Barnet grants a strong share of householder applications, but its Garden Suburb and Metroland conservation areas apply detailed roof- and frontage-design controls that shape loft and extension schemes. 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 Finchley, Golders Green and Hendon, 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 1930s semi-detached houses, this is the single biggest volume the roof can give — close to a full floor.
Roof form and the symmetry of paired 1930s houses are decisive for lofts. 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 Barnet 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 Barnet mansards come up most often:
Mansard loft drawings for Finchley's 1930s semis around Church End — roofline-matched, slate-detailed and drawn to Barnet Council's guidance.
Mansard loft drawings for Golders Green's Edwardian and interwar houses near Hampstead Garden Suburb — roofline-matched, slate-detailed and drawn to Barnet Council's guidance.
Mansard loft drawings for Hendon's interwar semi-detached estates — roofline-matched, slate-detailed and drawn to Barnet Council's guidance.
Mansard loft drawings for Mill Hill's detached houses and the Mill Hill conservation area — roofline-matched, slate-detailed and drawn to Barnet Council's guidance.
Mansard loft drawings for Edgware's Metroland semis with hipped roofs — roofline-matched, slate-detailed and drawn to Barnet Council's guidance.
Mansard loft drawings for Totteridge's large plots within the Green Belt and conservation area — roofline-matched, slate-detailed and drawn to Barnet 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 Barnet.
| Loft type | Planning route | Space gained | What Barnet 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 Hampstead Garden Suburb and Mill Hill, a mansard is judged on how it sits within the protected roofline of the terrace.
A fixed process built around how Barnet Council validates and decides mansard applications — most drawings are submission-ready within seven days of survey.
Send us your Barnet 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 Barnet 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 Barnet 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 Barnet 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 Barnet Council on every street, designated or not. On a terrace in a conservation area such as Hampstead Garden Suburb and Mill Hill 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. Barnet'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. Barnet 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 Barnet, a mansard is chosen when a dormer or hip-to-gable will not give enough room. Barnet 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, Barnet 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 Barnet 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 Barnet 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 Barnet Council approves, and we confirm the roofline case at the outset. Call 020 7864 7245 to start.
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