Building services in Westminster
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 Westminster
| Project | Guide range (inc VAT) |
|---|---|
| Kitchen extensions | £2,900–£4,400 per m² including a mid-range kitchen |
| Dormer loft conversions | £62,500–£88,500 for a typical rear dormer with en-suite |
| 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 |
Prices across London are typically 30% above the UK average for this kind of work, which is reflected in the range for Westminster.
Planning permission in Westminster
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 Westminster
Many London boroughs have conservation areas and detailed design guides, so early design advice saves time at the planning stage.
We work across Westminster and neighbouring areas such as Bermondsey, Brixton and Battersea. Postcodes we cover in Westminster include SW1.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions from homeowners in Westminster
Do you work in Westminster?
Yes. We take on extensions, loft conversions, conversions, renovations and new builds across Westminster, including postcodes SW1.
Do I need planning permission for an extension in Westminster?
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.
How much does a loft conversion cost in Westminster?
A rear dormer loft conversion in Westminster typically costs £62,500–£88,500 for a typical rear dormer with en-suite, including VAT.
Is the home visit free?
Yes. The first visit to discuss your project and measure up for a quote is free, with no obligation.
How much does an extension cost in Westminster?
A single-storey extension in Westminster 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.