Single-storey extensions in Hemel Hempstead

Covering Hemel Hempstead

Our coverage around Hemel Hempstead (HP3) also includes Berkhamsted (5 miles to the west) and St Albans.

Homes in the East of England

Across the East of England, newer estates often have integral garages and room for rear extensions, while older towns have Victorian terraces and conservation areas that shape what can be built.

What do you get with a single-storey extension?

A single-storey extension adds one level of new floor space to the back or side of a house, usually to open up a kitchen, dining or family room. It is the most common way to gain space without moving, and many can be built without a planning application.

Planning or lawful development certificate where needed
Foundations, drainage and structural steel
First-fix and second-fix electrics, plastering and making good

How much should I budget for a single-storey extension?

Typical ranges for single-storey extensions. Ground conditions, access and specification move the final figure, which we fix in writing before work starts.

Single-storey extensions	Guide price incl. VAT
Standard specification	£2,600 to £3,000 per m²
Good specification	£3,000 to £3,500 per m²
High specification	£3,500 to £4,000 per m²

Planning and building rules in Hemel Hempstead

In England we deal with the council’s planning team for permission or a lawful development certificate, with building control (the council or a registered building control approver) for inspections, and with neighbours under the Party Wall etc. Act 1996 where it applies.

In England a single-storey rear extension can often go ahead under permitted development: up to 3 m deep on an attached house or 4 m on a detached one, no higher than 4 m, with eaves no higher than 3 m within 2 m of a boundary. Deeper extensions, up to 6 m or 8 m, need prior approval from the council first.

What can affect a single-storey extension?

Drains under the footprint may need diverting or a build-over agreement with the water company.
Building on or near a shared boundary usually means serving a party wall notice in England and Wales.

How does the project run?

Tell us about the project. Call, use the guide price tool or send the form with a few photos and a postcode.
Free site visit. We measure up, look at access, drains and the structure, and talk through options and budget.
Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
Build and hand over. Our teams build to the programme, building control inspects, and you get the completion paperwork at the end.

Single-storey extensions: common questions

How much does a single-storey extension cost?

Most single-storey extensions cost about £2,600 to £4,000 per square metre including VAT, depending on specification, glazing and ground conditions. We give a fixed price in writing for the agreed specification after the survey.

Do I need planning permission for a single-storey extension?

Often not in England, if the extension stays within permitted development limits: 3 m deep on an attached house or 4 m on a detached house, and no higher than 4 m. Larger ones need prior approval or a planning application. Wales, Scotland and Northern Ireland have their own rules.

How do I get a price for single-storey extensions in Hemel Hempstead?

Use the guide price tool for a ballpark figure, then book a visit for a fixed written price for the agreed specification.

Also covering

Learn more about single-storey extensions, or see every project we cover in Hemel Hempstead.