Loft conversion drawings in Barnet

What the national rules allow in a Barnet loft

Under permitted development, a loft is limited by volume: 40 m³ (terrace house) / 50 m³ (any other house) additional roof volume. Earlier roof additions count. The enlargement also may not go higher than the existing roof, and the front slope is protected: No enlargement beyond the plane of a roof slope that forms the principal elevation and fronts a highway.

The design must also keep to the eaves line: Original eaves maintained; enlargement set at least 0.2 m from the eaves measured up the roof slope, so far as practicable (not required for hip-to-gable or roofs joining a rear/side extension). A balcony is not allowed: No verandah, balcony or raised platform. Inside a conservation area the position changes: Class B roof enlargements are not permitted development on article 2(3) land.

Heritage, Article 4 directions and the Green Belt

Barnet has 16 conservation areas and publishes 15 Article 4 directions, mapped across 48 areas. Historic England records 651 list entries here. Any of these can mean a loft that would be permitted elsewhere needs an application, so we look the address up before we quote a route.

About 28 per cent of the borough is Green Belt, and the council publishes 718 tree preservation orders, which we also check.

Barnet's decisions and appeals

Barnet decided 1,361 householder applications in its latest published year. It granted 80.2 per cent and decided 95.1 per cent within eight weeks or an agreed extension. Those figures cover all householder work, not only lofts.

The Planning Inspectorate figures show how often the council's refusals are tested. Over the latest five-year period, 413 householder appeals were decided, and 50.6 per cent were allowed. That is a borough-wide figure for all householder appeals, so it is context and not a forecast. It does tell us that a refusal on a loft is not always final, and that a clear, well-evidenced application is worth the effort first time.

Permitted development or planning permission for a Barnet loft

If the house is outside every constraint above and the loft stays within the limits, a Lawful Development Certificate in Barnet confirms it in writing. If not, the work needs householder permission, drawn as in our planning drawings in Barnet. Listed houses are separate again, as they need their own consent for most roof alterations.

Stairs, fire safety and what the drawings include

The building regulations apply either way. Where full stair headroom is not available: Loft conversions where 2.0 m cannot be achieved: 1.9 m at the centre of the stair, 1.8 m at the side (half width). A new storey above the stated height needs protection: New storey above 4.5 m by loft conversion: protect the full escape route with fire-resisting doors (min E 20) and partitions (min REI 30). Our building regulations drawings in Barnet carry that detail.

A Barnet loft set shows existing and proposed plans, the stair, a section through the roof, all elevations and the location and block plans. The price starts at £695 with VAT included. A second chartered technologist checks every sheet, and we redraw free of charge if the council asks for changes.

Other services and neighbouring councils

To plan a specific roof shape, see dormer loft conversion drawings in Barnet or L-shaped dormer drawings in Barnet. Adding to the back too? See house extension drawings in Barnet. The overview is architectural drawings in Barnet. Compare the rules next door in Brent and Camden.