Covering Amersham
We work in Amersham (HP7) and the places around it, including Beaconsfield, High Wycombe and Rickmansworth.
Homes in the South East
Many South East homes are inter-war or post-war semis and detached houses with room for rear and side extensions, while historic town centres and villages bring conservation area and listed building controls.
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
- Staircase, insulation and plasterboard
- En-suite, electrics and fire-protected escape route
What is the guide price for a dormer loft conversion in Amersham?
Indicative costs for dormer loft conversions. London and the South East usually sit towards the top of each range.
| 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 |
What approvals does a dormer loft conversion need in England?
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?
- Dormer cheeks close to a shared wall can trigger the Party Wall Act.
- A flat dormer roof needs proper falls and a quality membrane.
What happens after I enquire?
- Send us the details. Give us a postcode, a rough idea of size and some photos, by phone, form or the guide price tool.
- 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.
Dormer loft conversions: common questions
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.
How long does a dormer conversion take?
Around 8 to 12 weeks on site.
Do you work in Amersham?
Yes. Amersham is within our coverage for dormer loft conversions, along with nearby Beaconsfield and High Wycombe.
Other towns nearby
- Dormer loft conversions in Beaconsfield
- Dormer loft conversions in High Wycombe
- Dormer loft conversions in Rickmansworth
- Dormer loft conversions in Berkhamsted
Learn more about dormer loft conversions, or see every project we cover in Amersham.

