Dormer loft conversions in Carshalton

Covering Carshalton

We work in Carshalton (SM5) and the places around it, including Sutton, Mitcham and Morden.

Homes in London

Terraced houses dominate many London neighbourhoods, so most projects involve shared walls, narrow access and a party wall process. Conservation areas are widespread, and some boroughs have their own mansard and basement guidance.

What is a dormer loft conversion?

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.

Lawful development certificate or planning drawings
Steelwork and new floor structure
Dormer frame, roof covering and cladding

What is the guide price for a dormer loft conversion in Carshalton?

Guide prices for dormer loft conversions, including VAT where it applies. Your fixed price is confirmed in writing after the survey.

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

How is a dormer loft conversion approved in Carshalton?

English projects need planning clearance from the local council, building regulations sign-off from building control, and party wall notices where the work is on or near a shared boundary. We prepare and manage all three.

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.

From first call to completion

Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
Price and paperwork. The design is priced line by line, and we submit the planning and building control applications.
We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.

Your questions answered

How much does a dormer loft conversion cost?

Typically £50,000 to £80,000 including VAT, and up to around £90,000 for an L-shaped dormer.

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.

Do you work in Carshalton?

Yes. Carshalton is within our coverage for dormer loft conversions, along with nearby Sutton and Mitcham.

Dormer loft conversions in nearby towns

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