Single-storey, double-storey, rear and side extension drawings for Barnet homes — measured to Barnet Council's design guidance, delivered in days and revised free until your decision, with a free approval-odds check before you commit.
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.
Barnet homes come in a handful of recurring shapes, and each one points to a different extension. The borough is built largely from 1930s semi-detached houses, Hampstead Garden Suburb cottages and houses and postwar and detached homes, so a Victorian terrace usually wants a rear or side-return infill, while an interwar semi has room for a wider single-storey wrap or a two-storey side addition. Barnet Council judges every one of them against Barnet Local Plan and the Residential Design Guidance SPD, weighing footprint, height and the impact on the house next door before it looks at the elevations.
That is why the drawings decide the outcome. We set the extension depth against the permitted-development limits precisely, keep the eaves and ridge within the allowances, and plot the 45-degree daylight lines to the neighbours' windows so the case officer can see the amenity test is passed. Hampstead Garden Suburb schemes are assessed against the Suburb's own design code as well as council policy, so we design around it from the first sketch rather than discover it at validation.
Barnet also protects whole streets — Hampstead Garden Suburb, Mill Hill, Monken Hadley, Totteridge and Finchley (Church End) among them. 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. On designated land the larger-home extension route and most side extensions stop being permitted development, so we confirm your address against those layers before drawing a line.
Plenty of Barnet extensions are permitted development and need no planning application — a single-storey rear extension within the depth and height limits is the common case. You will normally need to apply to Barnet Council if any of these apply:
We draw the footprint, the ridge and eaves heights and the neighbours' daylight on the page — the relationships Barnet Council's officers weigh first — and submit a validation-complete pack, whether that is a lawful development certificate, a prior-approval notification or a full 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 complete, policy-literate extension pack anticipates those pressure points before submission, which is why professionally drawn applications are decided faster and refused less often than DIY ones.
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 Finchley, Golders Green and Hendon, the extension that lands most often is the single-storey rear addition — a glazed kitchen-diner across the back of the house, kept within the permitted-development depth or taken to a full application where the ground floor wants more. On the borough's 1930s semi-detached houses, a side-return infill frequently pairs with it to square off the plan; on wider postwar and detached homes, a two-storey side or rear extension can add a bedroom above without swallowing the garden.
Roof form and the symmetry of paired 1930s houses are decisive for lofts. We size the extension to the amenity and daylight tests, match the roof and materials to the host house, and keep enough garden to satisfy Barnet Council's space standards — so the scheme answers the borough's questions before an objection can raise them. Where permitted-development rights are used up or removed, we prepare the householder application to the council's extension design guidance instead.
We draw extensions on every street in the borough. A few of the neighbourhoods where Barnet projects come up most often:
Extension drawings for Finchley's 1930s semis around Church End — footprint-checked, daylight-tested and drawn to Barnet Council's guidance.
Extension drawings for Golders Green's Edwardian and interwar houses near Hampstead Garden Suburb — footprint-checked, daylight-tested and drawn to Barnet Council's guidance.
Extension drawings for Hendon's interwar semi-detached estates — footprint-checked, daylight-tested and drawn to Barnet Council's guidance.
Extension drawings for Mill Hill's detached houses and the Mill Hill conservation area — footprint-checked, daylight-tested and drawn to Barnet Council's guidance.
Extension drawings for Edgware's Metroland semis with hipped roofs — footprint-checked, daylight-tested and drawn to Barnet Council's guidance.
Extension drawings for Totteridge's large plots within the Green Belt and conservation area — footprint-checked, daylight-tested and drawn to Barnet Council's guidance.
The right extension in Barnet depends on your house type and how much garden you can give up. This is how the main options compare on planning route and what they add.
| Extension type | Permitted development? | What it adds | What Barnet Council checks |
|---|---|---|---|
| Single-storey rear | Often, within 3m/4m depth (6m/8m via prior approval) | Bigger kitchen-diner across the back | Depth, height, neighbour daylight (45°) |
| Side-return infill | Sometimes, if within width and height limits | Squares off an L-shaped ground floor | Width vs the original house, glazing to boundary |
| Two-storey rear/side | No — full application | Extra bedroom or bathroom above | Bulk, overlooking, 7m rear-boundary gap |
| Wraparound (rear + side) | No — full application | Whole-width open-plan ground floor | Combined footprint and garden retained |
Route depends on your street — conservation areas such as Hampstead Garden Suburb and Mill Hill and Article 4 directions can remove permitted-development rights.
A fixed process built around how Barnet Council validates and decides householder extension applications — most drawings are submission-ready within seven days of survey.
Tell us your Barnet postcode and house type. We confirm your conservation and Article 4 status, how much permitted-development depth you have left, and score your odds against live Barnet Council decisions.
We measure the existing footprint, floor and eaves levels, boundary distances and the neighbours' window positions — the numbers the depth limits and daylight tests depend on.
Chartered designers develop the single-storey, two-storey or side extension to your brief, drawn inside the permitted-development limits or to Barnet Council's extension design guidance.
We submit the certificate, prior-approval notice or application, manage validation and case-officer queries, and revise the drawings free until Barnet Council issues its decision.
Not always. A single-storey rear extension up to 3 metres deep on a terrace or semi, or 4 metres on a detached house, and no higher than 4 metres, is usually permitted development. In Barnet you will need to apply to Barnet Council for two-storey extensions, side extensions wider than half the house, anything forward of the front wall, deeper rear extensions under the larger-home prior-approval route, and any extension in a conservation area such as Hampstead Garden Suburb and Mill Hill.
Standard permitted development allows 3 metres on a terraced or semi-detached house and 4 metres on a detached one. The larger-home extension scheme can double that to 6 or 8 metres, but it needs a prior-approval notification to Barnet Council and a neighbour-consultation period, and it does not apply on designated land such as Barnet's conservation areas. We confirm which route your property qualifies for before drawing.
Two-storey and double-storey extensions almost always need a full householder application to Barnet Council, because they fall outside permitted development on most homes. The council looks closely at bulk, overlooking of neighbours and the 7-metre gap a two-storey rear extension must keep from the rear boundary. We design to those tests and show the daylight and privacy angles on the drawings.
A householder planning application in Barnet runs to a statutory eight-week target, a larger-home prior-approval notification to around six weeks including the neighbour-consultation period, and a lawful development certificate to eight weeks. Incomplete submissions stall at validation, so we submit a complete pack and manage officer queries to keep the decision on schedule. Barnet Council is the decision-maker.
Yes — planning permission and building regulations are separate consents, and almost every extension needs both. Planning governs whether you can build it; building control governs how it is built, covering structure, insulation, drainage and fire safety. We prepare the building-regulations drawings alongside the planning set so Barnet Council's building control or an approved inspector can sign the work off.
Every house and brief is different, so we price each Barnet extension individually and send a fixed, no-obligation quote back within one working day. It covers the full drawing pack with free revisions until Barnet Council approves, and we tell you upfront whether your extension qualifies as permitted development. Call 020 7864 7245 to get started.
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Same fixed quotes, same fast drawings — wherever your project is.