House extensions in Hemel Hempstead
We design and build house extensions for homes in Hemel Hempstead and the surrounding Hertfordshire area, with guide prices adjusted for the region.
- Postcode districtsAL3, HP1, HP2, HP3, WD4, WD5
- Price regionEast of England (×1.06)
- Planning rulesEngland
- Site visitFree, no obligation
Approvals for an extension in Hemel Hempstead
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 single-storey side extension can be permitted development if it is no more than 4 m high and no wider than half the width of the original house. Two-storey side extensions, and any side extension on designated land such as a conservation area, need a householder planning application.
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.
Building regulations approval is separate from planning. In England you can use the council's building control team or a registered building control approver; a full plans application gets the drawings checked before work starts, and the inspector signs the work off with a completion certificate.
Applications are decided by the local planning authority (your district, borough or unitary council).
Guide prices for Hemel Hempstead
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) |
|---|---|---|
| Orangery extensions | 16 m² | £47,000 – £59,500 |
| Side return extensions | 11 m² | £27,500 – £35,000 |
| Double-storey extensions | 32 m² | £61,000 – £80,000 |
| Conservatory replacement extensions | 14 m² | £31,500 – £41,000 |
| Kitchen extensions | 20 m² | £44,500 – £56,500 |
Covering Hemel Hempstead and nearby
We cover Hemel Hempstead and the postcode districts AL3, HP1, HP2, HP3, WD4, WD5. The same team covers Berkhamsted (5 miles), St Albans (5 miles), Harpenden (6 miles), Watford (7 miles), Rickmansworth (8 miles), all within easy reach. Chesham, in Buckinghamshire, is roughly 7 miles from Hemel Hempstead and also on our list.
Which extension suits a Hemel Hempstead home?
Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.
Depending on the plot, double-storey extensions and bungalow extensions are often the strongest options, with wraparound extensions worth considering where there is room.
Every extension type in Hemel Hempstead
- Utility and boot room extensions · from £14,500
- Pitched roof extensions · from £23,500
- Single-storey rear extensions · from £22,000
- Porch extensions · from £4,200
- Side extensions · from £23,000
- Wraparound extensions · from £38,000
- Orangery extensions · from £31,500
- Home office extensions · from £16,500
- Extensions over a garage · from £25,000
- Double-storey extensions · from £40,000
- Planning permission for extensions · from £350
- Building regulations for extensions · from £950
- Extension plans and drawings · from £1,250
- Bedroom extensions · from £27,500
- Annexe extensions · from £58,000
- Flat roof extensions · from £22,000
- Glass box extensions · from £31,500
- Timber frame extensions · from £22,000
- Side return extensions · from £19,000
- Conservatory replacement extensions · from £21,000
- Bungalow extensions · from £27,500
- Kitchen extensions · from £28,500
Free site visit
It starts with a visit to your house to measure, check access and talk through ideas and budget.
Design and approvals
We produce the drawings and structural design, and manage the approvals so they are in place before work starts.
Fixed written price
We confirm the build price in writing, based on the approved drawings and the finishes you have chosen.
Build and sign-off
We build it with one project manager, book the building control inspections and hand over the completion certificate.
Questions about extensions in Hemel Hempstead
How much does an extension cost in Hemel Hempstead?
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 Hemel Hempstead?
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.
Can I get a price before anyone visits?
Yes. This page shows guide prices adjusted for Hemel Hempstead, and the guide-price tool gives a range for your own size and finish in about a minute.
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.
Book a free site visit in Hemel Hempstead
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.