Aerial view of London suburban rooftops and rear gardens across a borough like Barnet

Barnet · London

Double Storey Extension Drawings in Barnet

Fixed-fee, MCIAT-chartered double storey extension drawings for Barnet homeowners — London Borough of Barnet validation and local constraints handled from the start.

Barnet's housing is dominated by interwar semi-detached suburbia across Finchley, Hendon and Edgware — homes ideal for hip-to-gable and dormer loft conversions and rear extensions, which frequently qualify as permitted development on semi-detached houses within the volume limits. But the borough also contains Hampstead Garden Suburb, one of the most tightly controlled residential areas in the country, so the correct route depends entirely on which part of Barnet you are in rather than on the house type alone.

Within the Suburb, an Article 4 direction removes almost all permitted development rights — one of the most far-reaching in London — and the Hampstead Garden Suburb Trust must also consent to external changes in parallel with the London Borough of Barnet. The borough's other conservation areas, Mill Hill, Monken Hadley, Totteridge and Finchley Church End, apply their own controls on 1930s semi character and front elevations, and the greens at Totteridge and Monken Hadley add further sensitivity. Elsewhere, Barnet's interwar semis usually retain permitted development rights for rear extensions and lofts.

We tailor Barnet applications to the specific area: straightforward permitted-development lofts and extensions across Finchley and Edgware, confirmed with a Lawful Development Certificate where they qualify, and carefully evidenced full applications within the Suburb and conservation areas. In the Suburb we handle both tracks — a design-led planning application to Barnet and the Trust's requirements — since approval there depends on respecting the Arts-and-Crafts character precisely. The fee is fixed and agreed up front, typically around 30% below an architect's charge for the same council-accepted drawings, with free redraws until Barnet approves. Drawing to the validation checklist, and turning drawings around in roughly seven days, keeps most householder applications inside the statutory eight-week determination, with the elevations and materials detail the council expects.

Proposed floor plan

Barnet

Planning in Barnet: what to know before you apply

The Hampstead Garden Suburb Article 4 direction is among the most far-reaching in London, controlling almost all external alterations and requiring Hampstead Garden Suburb Trust consent in parallel with planning. Elsewhere, Barnet's 1930s semis usually retain permitted development rights for rear extensions and lofts.

Typical Barnet housing stock

1930s semi-detached suburbia across Finchley, Hendon and Edgware, with the nationally significant Arts-and-Crafts housing of Hampstead Garden Suburb.

Areas we regularly draw for in Barnet

Finchley · Edgware · Hendon · Golders Green · Mill Hill · Chipping Barnet · Whetstone

What the numbers say about Barnet planning decisions

These are London Borough of Barnet’s own reported figures, published by government rather than estimated by us. They are what we design against — a borough that refuses one householder application in five needs a different drawing package from one that refuses one in twenty.

Permitted development in Barnet

Larger householder extensions put to London Borough of Barnet under the prior-approval route, and lawful-development certificates decided, over eight quarters.

Prior approval not requiredWent ahead without a full application	364
Prior approval granted	30
Prior approval refused	210
Granted where a decision was neededFrom 240 determinations	12%
Building upwards, prior approval refused	0
Certificates of lawful development decided	1,664

Source: Ministry of Housing, Communities and Local Government (PS1 district planning application statistics). Open Government Licence v3.0 Extracted 2026-08-16.

What removes permitted development in Barnet

Live entries on the national planning registers for London Borough of Barnet. Article 4 directions withdraw permitted development rights, so a project inside one needs a full application rather than prior approval. Revoked and expired entries are excluded.

Article 4 directions in force	15
Areas they coverOne direction can cover many separate areas	48
Conservation areasPermitted development is already narrower inside one	16

Source: MHCLG Planning Data Platform. Open Government Licence v3.0 Extracted 2026-08-16.

Double Storey Extension Drawings for Barnet homes: the package and the process

At first-floor level the drawings have to answer for daylight, privacy and massing. That means proposed elevations showing every new window with its position relative to the boundary, a section taken through the extension and the neighbouring building, and a roof form drawn to sit below the existing ridge rather than compete with it.

We draw the neighbouring property alongside your own, because the officer's assessment is comparative — the effect on their windows and outlook is the test. Setting the first floor in from the boundary, and showing that set-back as a dimension, resolves most objections before consultation begins.

At first floor the boundary relationship decides everything. A detached house has room to set the addition in on both sides; a semi has one shared wall and one clear flank; a mid-terrace can usually only go to the rear, where the effect on both neighbours has to be drawn.

Do I need planning permission for a double storey extension in London?

Almost always. Permitted development rights for two-storey extensions are far more restrictive than for single-storey work, particularly on how close the new structure can come to a boundary and how closely its roof pitch and eaves height must match the existing house, so most double storey projects are drawn and submitted as full householder planning applications rather than relying on permitted development.

Where the property sits in a conservation area or is subject to an Article 4 direction, any remaining permitted development allowance for a second storey is typically removed entirely, reinforcing the need for a full application. We check your property's status and your borough's design guidance before drawing.

How do councils control the impact of a double storey extension on neighbours?

Because a second storey introduces new windows and massing at first-floor level, London boroughs apply design guidance aimed specifically at protecting neighbouring light, privacy and outlook.

The 45-degree rule, tested at neighbouring windows, to check the extension does not block an unreasonable amount of daylight
A common design expectation that a two-storey side extension is set in roughly 1 metre from the shared boundary, rather than built hard against it
A first floor commonly set back from the ground floor front elevation, so the upper storey reads as subordinate to the main house from the street
Obscure or high-level glazing on flank walls facing directly into a neighbour's garden or windows, to limit overlooking

Matching the roofline and materials

Planning officers assess a double storey extension heavily on how convincingly it reads as part of the original house rather than an addition bolted onto the side. Our drawings match ridge height, roof pitch, eaves detail and brick or render finish to the existing building wherever the design brief allows, which is consistently one of the strongest factors in securing approval without delay or redesign. Where a subtly contrasting material is proposed instead — a different brick tone, or a zinc or slate roof against a tiled original — we set it out clearly on the elevations so the design intent reads as deliberate rather than a mismatch, which is how most London boroughs prefer a genuine design statement to be presented.

Extending once vs twice: single versus double storey
Option	What it adds	Typical fee
Single-storey rear extension	A ground-floor kitchen-diner only, may qualify for permitted development	see Rear Extension Drawings, from £1,100
Double storey side or rear extension	Two rooms across two floors, usually needs full planning	Full Planning pack ~£1,600–£2,400
Double storey + Building Regulations (structural)	Combined pack including structural calculations for two-floor loads and foundations	Planning + Building Regs pack ~£2,200–£3,850
Wraparound (rear + side return)	Combines two single-storey extensions into one L-shaped ground floor	see Wraparound Extension Drawings, from £2,200

Sheet from a double storey extension drawings package prepared for a Barnet property, drawn to London Borough of Barnet validation standards — A sheet from the double storey extension drawings package we submit to London Borough of Barnet.

Local Areas

Double Storey Extension Drawings across Barnet

Also in Barnet

Planning Permission Planning Drawings Architectural Drawings Building Regulations Drawings Loft Conversion Drawings Double Storey Extension Drawings across London

FAQ

Double Storey Extension Drawings in Barnet — FAQs

How much does a double storey extension cost to design in London?+

Double storey extension drawings start from £2,400, covering full planning permission and structural design for the additional floor. A combined planning and building regulations package with full structural calculations runs up to around £3,850, fixed and agreed upfront.

Do I need planning permission to add a second storey?+

In almost all cases, yes. Permitted development rights for two-storey extensions are much tighter than for single-storey work, particularly around boundary distance and roof matching, so we design double storey projects on the assumption a full householder planning application is required.

Will a double storey extension overlook my neighbour's garden?+

That is exactly what planning officers check, using the 45-degree daylight rule alongside boundary set-in and first-floor set-back guidance. Where a new flank window would look directly into a neighbour's garden, we typically specify obscure or high-level glazing to address it before submission rather than after an objection.

Do I need an architect for a double storey extension?+

No. DrawingsDirect is an MCIAT-chartered architectural technologist practice, producing the same council-accepted drawings and in-house structural coordination as an architect, for a fixed fee typically around 30% lower, with structural calculations for the additional floor produced by the same team rather than a separately appointed engineer.

How long does it take to get double storey extension drawings?+

Drawings are typically ready around 7 days from survey. A householder planning application then has a statutory 8-week determination period once submitted.

Do I need planning permission for a loft or extension in Barnet?+

Across Finchley, Edgware and Hendon, Barnet's 1930s semis usually keep permitted development rights for rear extensions and hip-to-gable or dormer lofts, so a full application isn't always needed. The major exception is Hampstead Garden Suburb, where an Article 4 direction removes almost all permitted development rights. We check your address first and confirm permitted development with a Lawful Development Certificate where it applies.

What is different about building in Hampstead Garden Suburb?+

The Suburb has one of the most far-reaching Article 4 directions in London: almost all external alterations need planning permission, and the Hampstead Garden Suburb Trust must also consent to changes in parallel with the council. We handle both tracks — a carefully evidenced planning application to Barnet and the Trust's design requirements — since approval there depends on respecting the Arts-and-Crafts character precisely.

Is a hip-to-gable loft conversion allowed on my Barnet semi?+

Usually, yes. The borough's abundant interwar semis are well suited to hip-to-gable and dormer conversions, which frequently qualify as permitted development on semi-detached homes within the volume limits. Outside conservation areas and the Suburb, this is often the quickest route. We confirm eligibility, then produce the planning and building-regulations drawings.

How long does Barnet take to decide an application?+

Barnet determines most householder applications within the statutory eight-week period once validated; Suburb and conservation cases can involve additional consultation. We prepare Barnet submissions to the validation checklist, with the elevations and materials detail the council expects, to avoid the drawing queries that are the usual cause of delay.

How much do Barnet planning drawings cost?+

We agree a fixed fee before we start, typically around 30% below an architect's fee for the same council-accepted drawings, with free redraws until Barnet approves. A straightforward Finchley loft and a Hampstead Garden Suburb application differ in the evidence required, so we quote once we have seen the project and know which route applies.

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