New house design drawings for a large plot in Totteridge N20, London Borough of Barnet

Totteridge · N20 · Barnet

Dormer Loft Conversion Drawings in Totteridge N20

Fixed-fee, MCIAT-chartered dormer loft conversion drawings for Totteridge (N20) homeowners — London Borough of Barnet validation and local constraints handled from the start.

Totteridge (N20) runs along a green ridge of large detached houses, former farmhouses and villas on deep plots with paddocks and mature trees, and that semi-rural grain shapes the generous but carefully judged extensions we draw here.

Because the conservation area has carried Article 4 directions since 1970 that remove PD rights for extensions, roofs, porches and outbuildings, we check the boundary and any Green Belt overlap before advising whether a scheme needs a full application.

Proposed floor plan

Totteridge N20

Totteridge (N20) — planning at a glance

Council: London Borough of Barnet
Postcode district: N20
Planning portal: View the Barnet planning portal
Housing stock: Large detached houses, former farmhouses and villas set along the ridge of Totteridge Lane and Totteridge Village, on deep plots with paddocks, mature trees and green verges giving the area its semi-rural character.
Article 4: The Totteridge Conservation Area has carried Article 4 directions since shortly after designation in 1970, removing permitted-development rights for extensions, roof and porch alterations and outbuildings across the area.
Conservation: Totteridge Conservation Area
Sample streets: Totteridge Lane · Totteridge Village · Grange Avenue · Barnet Lane
Local constraints: Totteridge Article 4 directions remove permitted-development rights for extensions, roof alterations, porches and outbuildings across the conservation areaThe semi-rural ridge setting with Green Belt land nearby constrains footprint, height and outbuilding schemesMature trees, verges and paddock boundaries bring tree-protection and landscape-character considerations on larger schemes

Planning in Totteridge (N20): what to know before you apply

Totteridge extensions almost always run as full householder applications to Barnet, since the long-standing Article 4 directions remove the permitted-development route across the conservation area. We prepare a heritage-and-landscape-aware set, checking tree constraints and any Green Belt overlap before submission.

Typical Totteridge housing stock

Large detached houses, former farmhouses and villas set along the ridge of Totteridge Lane and Totteridge Village, on deep plots with paddocks, mature trees and green verges giving the area its semi-rural character.

Streets we regularly draw for in Totteridge

Totteridge Lane · Totteridge Village · Grange Avenue · Barnet Lane

What N20 is actually built of

Measured from 391 classified residential buildings in N20, not from a description of the area.

Totteridge N20 housing mix

Residential building form across the N20 postcode district, from 391 classified buildings.

Attached on more than one side	23%
Attached on one side	54%
Detached	24%
Median building footprint	93 m²
Addresses per buildingAbove about 2 means flats and maisonettes dominate	1.42
Buildings classified	391

Source: Ordnance Survey National Geographic Database (derived statistics). Contains OS data © Crown copyright and database right 2026. Contains Royal Mail data © Royal Mail copyright and database right 2026. Extracted 2026-08-17.

Dormer Loft Conversion Drawings for Totteridge (N20) homes: the package and the process

A rear dormer is drawn to a tight set of geometric tests: the volume it adds, its set-back from the eaves, whether it sits below the ridge line, and how it meets the roof slope at the sides. Each of those is a dimension on the drawing rather than a description, because that is how the case is assessed.

Side-facing windows and the cheek treatment are where dormer schemes most often attract conditions. We show glazing type and opening restrictors on the elevations, and detail the cheeks and roof junction on the section, so the approved drawing is one your builder can work from without reinterpretation.

The rear roof slope is the whole opportunity. A house with a rear outrigger can carry an L-shaped dormer over both roofs, while a simple double-pitch roof takes a box dormer and nothing more — and a shallow pitch may not give usable height under either.

Is a rear dormer loft conversion permitted development in London?

A single rear dormer is the loft conversion most likely to qualify as permitted development in London, provided it stays within the volume allowance — 40 cubic metres for terraced houses, 50 cubic metres for detached and semi-detached homes. The dormer must not extend beyond the highest part of the existing roof, should be set back from the eaves where practical, and is normally finished in materials that match the existing roof. Where the numbers work, we recommend a Lawful Development Certificate rather than a full planning application, because it is faster and gives you a legal record that the work was lawful.

Box dormer or L-shaped dormer — which suits a London terrace?

A box dormer is a simple flat-roofed addition set into the rear roof slope, adding headroom and floor area over the main roof void. An L-shaped dormer links that main-slope dormer to a second dormer over the rear closet wing — the small rear addition found on most Victorian and Edwardian London terraces — and is popular because it captures far more usable space over the stairwell for a similar planning risk. Both are generally assessed the same way for permitted development, but the closet-wing element of an L-shaped dormer needs its own structural support, which we detail on the drawings and coordinate with the structural calculations.

Box dormer: single flat-roofed addition on the main rear slope
L-shaped dormer: main-slope dormer combined with a closet-wing dormer
Both are typically finished in matching brick, tile-hung or render to suit the host roof

Do front dormers need planning permission?

Permitted development for roof alterations generally excludes elevations that front a highway, so a dormer on the front roof slope facing the street almost always needs a full householder planning application, even where a rear dormer on the same house would be permitted development. Front dormers are also more visible to the council and to neighbours, so proportion, materials and set-back from the ridge and eaves carry more weight in the assessment. We draw front dormers to sit comfortably within the roofline rather than dominating it, which is what most validation teams are looking for, and where a front dormer alone will not deliver the space you need, we assess whether combining it with a rear dormer or rebuilding the rear slope as a mansard makes more sense.

Typical dormer loft conversion drawing packages
Dormer type	Typical route	Structural scope	Fee from
Single rear box dormer	Permitted development / LDC	Standard joist and beam upgrade	£1,100
L-shaped rear dormer	Permitted development / LDC	Additional closet-wing support	£1,300
Front dormer	Householder planning	Standard joist and beam upgrade	£1,600
Dormer in a conservation area	Householder planning	Standard joist and beam upgrade	£1,600

Sheet from a dormer loft conversion drawings package drawn for a Totteridge property in N20, showing the existing and proposed arrangement at scale — A sheet from the dormer loft conversion drawings package we submit to London Borough of Barnet for Totteridge (N20) properties.

Also in Totteridge N20

Planning Permission Planning Drawings Architectural Drawings Building Regulations Drawings Loft Conversion Drawings Dormer Loft Conversion Drawings across Barnet Dormer Loft Conversion Drawings across London

FAQ

Dormer Loft Conversion Drawings in Totteridge N20 — FAQs

How much do dormer loft conversion drawings cost in London?+

A single rear box dormer on the permitted development route typically starts around £1,100 for a full drawing set. L-shaped and front dormers cost more because of the extra structural design and, for front dormers, the planning application itself — we quote a fixed fee once we have seen your roof.

Is my dormer definitely permitted development?+

Not automatically — it depends on the volume you are adding, which elevation the dormer sits on, and whether a conservation area or Article 4 direction applies to your address. We check this free before recommending a route, and if a previous loft or roof extension has already used up part of your allowance, we factor that into the calculation too.

How long do dormer loft conversion drawings take?+

Typically around 7 days from survey to a full drawing set delivered to your online portal, whether you are going down the Lawful Development Certificate route or full planning.

Will I need an architect for a dormer loft conversion?+

No — as MCIAT-chartered architectural technologists we produce the same council-accepted drawings an architect would, typically at a lower fee, with structural calculations coordinated in-house.

What if my roof suits a different loft conversion type?+

If your roof is hipped, a hip-to-gable conversion may add more space than a dormer alone; if you are in a conservation area needing a full rebuild of the roof slope, a mansard may suit better. We assess your roof against all three before recommending one.

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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Tell us your Totteridge (N20) address and ambition — we'll confirm feasibility, local constraints and a fixed fee within one working day.