Covering Northolt
Northolt sits 11 miles west of London, with Greenford 1 miles to the south and Harrow 3 miles to the north-east.
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 does a dormer loft conversion involve?
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
- Steelwork and new floor structure
- Dormer frame, roof covering and cladding
What is the guide price for a dormer loft conversion in Northolt?
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 Northolt
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.
What can affect a dormer loft conversion?
- Dormer cheeks close to a shared wall can trigger the Party Wall Act.
- A flat dormer roof needs proper falls and a quality membrane.
How does the project run?
- 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.
- Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
- We build it. Work follows an agreed programme, with inspections at each stage and a final sign-off.
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.
How do I get a price for dormer loft conversions in Northolt?
Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.
Also covering
- Dormer loft conversions in Greenford
- Dormer loft conversions in Harrow
- Dormer loft conversions in Southall
- Dormer loft conversions in Brent
Learn more about dormer loft conversions, or see every project we cover in Northolt.

