L-shaped dormer drawings in Richmond upon Thames

Designations: the Richmond reality check

The council publishes 85 conservation areas, and Historic England lists 819 buildings inside the borough. One World Heritage Site, Kew Gardens, also falls within the boundary: the count is 1. Together they mean a large share of houses sit under some form of protection.

In a conservation area the national rule is: Class B roof enlargements are not permitted development on article 2(3) land. So wherever your house sits inside one of those areas, an L-shaped dormer is a full householder application with design and heritage justification, not a certificate.

Even outside the designated areas the borough is protective of roofscapes, which is why we show the dormer from the street, the garden and the neighbouring plot on the elevation sheets.

What Richmond decides, and how fast

The council handled 1,302 householder applications in the latest period and granted 83.3 per cent. It decided 98.3 per cent inside eight weeks or an agreed extension in the latest figures.

Treat those numbers as context. They describe every kind of householder scheme, from a porch to a basement, and not L-shaped dormers alone. What they do show is that a well-prepared roof application is processed promptly and is far from hopeless.

The thing that moves the odds on your own house is the drawings: a clear junction detail, honest materials, and a roof plan that proves the new volume sits within the original ridge.

Detailing the join, stair and fire route

Richmond officers want to see how the L meets the outrigger. Here the roof-join condition helps: Eaves-retention and 0.2 m set-back do not apply where the enlargement joins the original roof to the roof of a rear or side extension. We draw it as a single clean face to the garden, with tile or zinc cheeks chosen to match the existing roof.

Height cannot exceed the existing ridge: No part higher than the highest part of the existing roof. We dimension the ridge of the dormer against the original on the section so the officer can read it in a glance.

Behind the cladding sit the Building Regulations. The stair rule where full headroom is impossible is: 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). Adjoining owners on a Richmond terrace need notice too: Party structure notice at least 2 months before work. We prepare both sets of drawings together.

Costs and what the Mayor's levy means in Richmond

We do not publish a standard price for L-shaped work. After a free constraints check we give a fixed quote, VAT included, and we redraw at no charge if the council asks for changes.

The Mayoral levy for the borough falls in band 1, at £96.97 per square metre this year, and the borough also charges its own levy: £418.41/m² (Residential Higher Band); £317.99/m² (Residential Lower Band). Whether either applies to your dormer depends on the floor area the scheme creates, and our next-steps pack sets out the position.

Timing in Richmond is shaped by the designations more than by the council's speed. A heritage statement, a measured survey and, in some streets, pre-application advice all come before submission, so we ask for access to the roof space and the outrigger in the first week. With that done, the drawings are normally ready about a week after the survey, and the application can go in as soon as you have signed off the design.

Next steps and nearby boroughs

A simpler roof can be enough: compare dormer loft conversion drawings in Richmond upon Thames, or hip-to-gable loft conversion drawings in Richmond upon Thames if your semi has a hipped flank. The wider picture is in architectural drawings in Richmond upon Thames.

The same service is available over the river in Wandsworth, in Kingston upon Thames and in Hounslow. The general guide to the roof type is L-shaped dormer drawings.