Covering Borehamwood
Alongside Borehamwood, we also cover Barnet, Bushey (4 miles to the west) and Potters Bar.
Homes in the East of England
The East of England has a large stock of post-war and modern estate housing alongside period homes in market towns, which makes garage conversions, single-storey extensions and loft conversions popular.
What does a dormer loft conversion involve?
Rear dormers on terraced and semi-detached houses are often permitted development in England. We size the dormer to fit the volume allowance, clad it to suit the house (tile-hanging, render, slate or zinc) and fit out the room and en-suite below.
- Volume calculation and permitted development check
- Steelwork and new floor structure
- Dormer frame, roof covering and cladding
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 |
How is a dormer loft conversion approved in Borehamwood?
In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it 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.
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?
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- 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.
What people ask before starting
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.
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.
Can you visit a house in Borehamwood to quote?
Yes. After a short call we arrange a site visit to measure up and agree what the design needs to do, then send a written price.
Dormer loft conversions near Borehamwood
- Dormer loft conversions in Barnet
- Dormer loft conversions in Bushey
- Dormer loft conversions in Potters Bar
- Dormer loft conversions in Watford
Learn more about dormer loft conversions, or see every project we cover in Borehamwood.

