Single-storey extensions in Welwyn Garden City

Covering Welwyn Garden City

Welwyn Garden City sits 6 miles north-east of St Albans, with Hatfield 3 miles to the south and Hertford 6 miles to the east.

Homes in the East of England

The East of England has a large stock of post-war and modern estate housing alongside period homes in market towns, which makes garage conversions, single-storey extensions and loft conversions popular.

What is 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.

Measured survey and design drawings
Planning or lawful development certificate where needed
Foundations, drainage and structural steel

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

Guide prices for single-storey extensions, including VAT where it applies. Your fixed price is confirmed in writing after the survey.

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 Welwyn Garden City

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?

Building on or near a shared boundary usually means serving a party wall notice in England and Wales.
Kitchens and doors have long lead times, so we order them early.

What happens after I enquire?

Start with a conversation. A short call or the online form is enough for us to understand what you want to build.
Survey at your house. We look at the existing structure, services and access, and agree what the design needs to achieve.
Drawings, approvals, written quote. We prepare the design, apply for the approvals it needs, and give you a fixed price in writing.
Construction and completion. One site lead co-ordinates every trade through to the building control certificate.

Your questions answered

Do you need to dig up the drains?

Sometimes. If a public sewer runs under the extension, the water company has to agree a build-over or a diversion. We check this at survey stage.

Will the brick match?

We source the closest available match for colour, size and texture and agree a sample panel with you before laying.

How do I get a price for single-storey extensions in Welwyn Garden City?

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

Single-storey extensions near Welwyn Garden City

Learn more about single-storey extensions, or see every project we cover in Welwyn Garden City.