Building services in Harrow
House extensions
- Single-storey extensions
- Double-storey extensions
- Side extensions
- Side return extensions
- Wraparound extensions
- Kitchen extensions
- Orangeries
- Glazed and contemporary extensions
- Porches
Loft conversions
- Dormer loft conversions
- Hip-to-gable loft conversions
- Mansard loft conversions
- Rooflight loft conversions
- Bungalow loft conversions
Garage, basement and barn conversions
New build homes
Renovations and structural work
Design and approvals
Guide prices in Harrow
| Project | Guide range (inc VAT) |
|---|---|
| Dormer loft conversions | £62,500–£88,500 for a typical rear dormer with en-suite |
| Hip-to-gable loft conversions | £71,500–£101,500 for a hip-to-gable with rear dormer |
| Garage conversions | £23,500–£39,000 for a single integral garage |
| House renovations | £1,150–£2,350 per m² for a medium to full renovation |
| Structural alterations and knock-throughs | £5,750–£12,500 for a typical knock-through with steel beam |
| Porches | £8,500–£21,000 from a 3 m² porch to a small front extension |
The guide for Harrow reflects typical costs in London, roughly 30% above the UK-wide figure.
Planning permission in Harrow
In England a single-storey rear extension is often permitted development: broadly up to 3 metres deep on a semi-detached or terraced house and 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary, and covering no more than half the garden. The larger home extension scheme allows up to 6 or 8 metres if you notify the council first and neighbours have a chance to comment. In conservation areas, National Parks and National Landscapes the larger home extension route, side extensions and cladding are not permitted development. Flats and houses whose rights have been removed need a planning application, and listed buildings need listed building consent.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
About building in Harrow
Victorian and Edwardian terraces dominate many London streets, which is why side return, wraparound and mansard projects are so common here.
Our Harrow coverage includes postcode districts HA2, and we also work in nearby places such as Wembley, Pinner and Northolt.
How it works
- 01
Free visit
We look at the property, talk through what you want and measure up. There is no charge and no obligation.
- 02
Design and pricing
Design options, then a fixed quote based on the chosen drawings and specification.
- 03
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions from homeowners in Harrow
Do I need planning permission for an extension in Harrow?
In England a single-storey rear extension is often permitted development: broadly up to 3 metres deep on a semi-detached or terraced house and 4 metres on a detached house, no higher than 4 metres, with eaves no higher than 3 metres within 2 metres of a boundary, and covering no more than half the garden. The larger home extension scheme allows up to 6 or 8 metres if you notify the council first and neighbours have a chance to comment. In conservation areas, National Parks and National Landscapes the larger home extension route, side extensions and cladding are not permitted development. Flats and houses whose rights have been removed need a planning application, and listed buildings need listed building consent.
Is the home visit free?
Yes. The first visit to discuss your project and measure up for a quote is free, with no obligation.
Do you work in Harrow?
Yes. We take on extensions, loft conversions, conversions, renovations and new builds across Harrow, including postcodes HA2.
How much does a loft conversion cost in Harrow?
A rear dormer loft conversion in Harrow typically costs £62,500–£88,500 for a typical rear dormer with en-suite, including VAT.
How much does an extension cost in Harrow?
A single-storey extension in Harrow typically costs £2,550–£3,750 per m² of floor area, and a double-storey extension £2,150–£3,250 per m² of floor area (both floors), including VAT.