Extending your home in Borehamwood
We design and build house extensions for homes in Borehamwood and the surrounding Hertfordshire area, with guide prices adjusted for the region.
- Postcode districtsWD6, WD7
- Price regionEast of England (×1.06)
- Planning rulesEngland
- Site visitFree, no obligation
Borehamwood and surrounding towns
We cover Borehamwood and the postcode districts WD6, WD7. We also work in nearby Bushey (4 miles), Potters Bar (5 miles), Watford (5 miles), St Albans (7 miles), Hatfield (8 miles). Barnet, in Greater London, is roughly 3 miles from Borehamwood and also on our list.
Which extension suits a Borehamwood home?
Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.
Start by comparing wraparound extensions, double-storey extensions and bungalow extensions: between them they cover most of the layouts we see requested for houses like these.
Popular extension prices in Borehamwood
Prices on this page use our East of England factor of ×1.06, include VAT at 20% and cover the build; your written price follows a survey and agreed drawings.
| Extension type | Example size | Standard spec (inc VAT) |
|---|---|---|
| Extensions over a garage | 12 m² | £26,500 – £34,500 |
| Orangery extensions | 16 m² | £47,000 – £59,500 |
| Side return extensions | 11 m² | £27,500 – £35,000 |
| Wraparound extensions | 25 m² | £60,500 – £77,000 |
| Double-storey extensions | 32 m² | £61,000 – £80,000 |
| Kitchen extensions | 20 m² | £44,500 – £56,500 |
Approvals for an extension in Borehamwood
In England a single-storey rear extension can usually go up to 3 m beyond the original rear wall of a semi-detached or terraced house, or 4 m on a detached house, without a planning application, provided it is no more than 4 m high, keeps eaves to 3 m within 2 m of a boundary and, with other buildings, covers no more than half the land around the original house. The larger home extension prior approval scheme raises those depths to 6 m and 8 m, with neighbours notified and a 42-day decision.
In England a two-storey rear extension is permitted development only if it projects no more than 3 m from the original rear wall, sits at least 7 m from the rear boundary, matches the roof pitch and uses obscure, non-opening side windows upstairs. Most two-storey extensions therefore go through a householder planning application, which costs £548 from 1 April 2026 and normally takes about 8 weeks.
In a conservation area, national park, National Landscape, the Broads or a World Heritage Site the permitted development limits are tighter (no side or two-storey extensions without an application). Listed homes need listed building consent, and if permitted development rights have been removed, any extension needs an application.
If the work involves a shared wall, building on the boundary, or digging foundations within 3 m (sometimes 6 m) of a neighbour's building, the Party Wall etc. Act 1996 applies and notice must be served before work starts: two months for work to a party wall, one month for new walls on the boundary and for excavations.
Applications are decided by the local planning authority (your district, borough or unitary council).
Every extension type in Borehamwood
- Porch extensions · from £4,200
- Kitchen extensions · from £28,500
- Side extensions · from £23,000
- Annexe extensions · from £58,000
- Conservatory replacement extensions · from £21,000
- Glass box extensions · from £31,500
- Pitched roof extensions · from £23,500
- Double-storey extensions · from £40,000
- Extension plans and drawings · from £1,250
- Bedroom extensions · from £27,500
- Planning permission for extensions · from £350
- Single-storey rear extensions · from £22,000
- Building regulations for extensions · from £950
- Timber frame extensions · from £22,000
- Wraparound extensions · from £38,000
- Bungalow extensions · from £27,500
- Orangery extensions · from £31,500
- Side return extensions · from £19,000
- Utility and boot room extensions · from £14,500
- Flat roof extensions · from £22,000
- Extensions over a garage · from £25,000
- Home office extensions · from £16,500
Free site visit
We visit your Borehamwood home, measure up, talk through what you want and check the planning position.
Design and approvals
Drawings are prepared and agreed with you, then submitted for the right planning route and building regulations approval.
Fixed written price
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Work is carried out to the agreed programme, inspected by building control and signed off at the end.
Questions about extensions in Borehamwood
How much does an extension cost in Borehamwood?
Using our East of England factor (×1.06), a standard-spec single-storey extension of 20 m² is a guide £43,000 to £55,500 including VAT, and a 32 m² two-storey extension £61,000 to £80,000. Your written price follows the survey.
Do I need planning permission for an extension in Borehamwood?
Not always. It depends on the size, position and your property's history. Many single-storey rear extensions in England are permitted development or can use prior approval.
Do you handle building regulations?
Yes. We prepare the drawings and calculations, submit them and book inspections, ending with a completion certificate.
Who do I contract with?
Your contract is with S&K Property Investments and Improvement Ltd, which designs and manages the project and the build teams who carry it out.
Do you cover all of Borehamwood?
Yes, including the surrounding parts of Hertfordshire. Site visits are free and there is no obligation.
Book a free site visit in Borehamwood
We will measure up, check the planning position and give you honest guide figures.
- Free, no-obligation site visit
- Planning route checked before you spend on drawings
- Written price once the design is agreed
- Building control sign-off at the end
Prefer to talk? Call 0800 088 6341 or .
Book a free site visit
Tell us a little about the project and we will arrange a time.