Dormer loft conversions in Northamptonshire

Covering Northamptonshire

We cover Northamptonshire, including Northampton, Corby, Kettering and Wellingborough, and the towns around them.

Homes in the East Midlands

Across the East Midlands you find everything from city terraces to modern estates and stone villages, so the right extension depends a lot on the street and the materials around it.

What goes into 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
Staircase, insulation and plasterboard

How much should I budget for a dormer loft conversion?

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 Northamptonshire

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?

Dormer cheeks close to a shared wall can trigger the Party Wall Act.
L-shaped dormers are common on Victorian terraces with a rear outrigger.

How does the project run?

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
We visit and measure. A surveyor checks the house, the boundaries and the ground, and discusses what is realistic.
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

Is a dormer permitted development?

Rear dormers in England often are, within the 40 m³ (terrace) or 50 m³ (semi or detached) volume allowance. Front dormers facing a road are not.

How long does a dormer conversion take?

Around 8 to 12 weeks on site.

Do you work in Northamptonshire?

Yes. Northamptonshire is within our coverage for dormer loft conversions, along with nearby Northampton and Corby.

Also covering

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