Side extensions in Berkhamsted
A side extension in Berkhamsted starts with the right design and the right approval route. We take care of both, then build it with our own project management.
- Guide price in BerkhamstedFrom £23,000 inc VAT
- PlanningSingle storey can be permitted development
- Build time10–18 weeks on site
- Postcode districtsHP4
Planning and approvals in Berkhamsted
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.
Before any drawing is finalised we check whether the house is listed, in a conservation area or subject to an Article 4 direction.
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.
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).
Covering Berkhamsted
Postcode districts we cover around Berkhamsted include HP4. We also work in nearby Hemel Hempstead (5 miles), Rickmansworth (9 miles), Harpenden (10 miles), St Albans (10 miles).
Just over the Buckinghamshire border, Chesham is about 4 miles away. Across the East of England many houses sit on generous plots, and single-storey and wraparound extensions are a natural fit.
What should I budget for a side extension in Berkhamsted?
Labour and material costs vary across the UK, so for Berkhamsted we use our East of England factor (×1.06). The ranges include VAT and exclude design, structural and council fees.
Typical rates in Berkhamsted: £1,860 to £3,600 per m² including VAT, depending on specification.
| Size | Essential | Standard | Premium |
|---|---|---|---|
| 2.5 m × 5 m 12 m² | £23,000 – £28,000 | £26,000 – £34,000 | £33,000 – £43,500 |
| 3 m × 6 m 18 m² | £33,000 – £40,500 | £39,000 – £51,000 | £49,500 – £65,000 |
| 3 m × 8 m 24 m² | £44,500 – £53,500 | £52,000 – £67,500 | £66,000 – £86,500 |
Want a range for your exact size? The guide-price tool takes about a minute.
Is a side extension right for your house?
- Houses where the rear garden is small
- Detached and semi-detached houses with side land
- Homes needing a utility, study or ground-floor bedroom
Councils often prefer side extensions to sit slightly back from the front of the house with a lower roof, so the original building still reads clearly. We design to those principles from the start to avoid redesigns.
What happens next
Site visits are free and there is no obligation. Where drawings are needed, the design stage is priced in writing before it starts.
Free site visit
We visit your Berkhamsted home, measure up, talk through what you want and check the planning position.
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
The price is fixed in writing once the design is settled, with a clear programme and payment stages.
Build and sign-off
Our team builds the extension, keeps you updated weekly and finishes with building control sign-off.
Questions people ask about side extensions
Can I see a price before committing to anything?
Yes. The guide prices on this page are adjusted for Berkhamsted, and the guide-price tool gives a range for your own size. After the survey you get a written price before anything is agreed.
How long does a side extension take to build in Berkhamsted?
On site, typically 10 to 18 weeks once approvals are in place. Before that, allow 6–14 weeks design and approvals.
Do I need building regulations approval in Berkhamsted?
Yes. Almost every extension needs it, whatever the planning route. We prepare the drawings and book the inspections.
Can I build over my driveway?
Yes, if the foundations work and you keep any parking the council requires. Drains and services under drives are common, so we check before design.
How much does a side extension cost?
Our guide range is about £1,860 to £3,600 per m² including VAT, depending on specification, so a standard 18 m² single-storey side extension lands around £39,000 to £51,000 in Berkhamsted.
Book a free site visit in Berkhamsted
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.