Dormer loft conversions in Hanworth

Covering Hanworth

Our coverage around Hanworth (TW13) also includes Feltham, Sunbury-on-Thames and Hounslow.

Homes in London

London projects often mean working on period terraces with neighbours on both sides, tight access through the house and conservation area controls, so careful planning and party wall work matter as much as the build.

What is included in a dormer loft conversion in Hanworth?

A dormer loft conversion builds a box-shaped extension out from the rear slope of the roof, creating vertical walls and full head height across most of the new floor. It is the most popular type of loft conversion because it gives the most usable space for the cost.

Volume calculation and permitted development check
Lawful development certificate or planning drawings
Steelwork and new floor structure

What will a dormer loft conversion cost?

What dormer loft conversions typically cost. These are guide ranges; the written quote for your house replaces them.

Dormer loft conversions	Guide price incl. VAT
Rear dormer, bedroom only	£50,000 to £65,000
Full-width dormer with en-suite	£60,000 to £80,000
L-shaped dormer (over rear outrigger)	£65,000 to £90,000

Planning and building rules in Hanworth

Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 applies.

In England many loft conversions are permitted development: the extra roof volume must stay within 40 m³ on a terraced house or 50 m³ on a semi or detached house, nothing can sit higher than the existing ridge, no dormer can face a road on the main elevation, and side windows must be obscure-glazed and non-opening below 1.7 m. Houses in conservation areas, National Parks and National Landscapes cannot use these roof-extension rights, so dormers there need planning permission (a rooflight-only conversion can still be permitted development), and flats always need permission.

What can change the price or programme?

A flat dormer roof needs proper falls and a quality membrane.
L-shaped dormers are common on Victorian terraces with a rear outrigger.

What are the steps?

Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

What people ask before starting

How long does a dormer conversion take?

Around 8 to 12 weeks on site.

What cladding can a dormer have?

Tile-hanging to match the roof, render, slate, timber or zinc, depending on the house and any planning conditions.

Who deals with the council for a project in Hanworth?

We do. We prepare the drawings, submit planning or permitted development paperwork if needed, and arrange building control inspections.

Dormer loft conversions in nearby towns

Learn more about dormer loft conversions, or see every project we cover in Hanworth.