Bungalow and upward extensions in Hertfordshire

Covering Hertfordshire

We cover Hertfordshire, including Watford, Hemel Hempstead, Stevenage and St Albans, and the towns around them.

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 included in an upward extension in Hertfordshire?

An upward extension adds a new storey on top of an existing house, most often turning a bungalow into a two-storey or chalet-style home. It can double the floor area without using any of the garden.

Structural survey of walls and foundations
Design and planning or prior approval application
Roof removal and temporary weather protection

What will an upward extension cost?

Use these ranges to budget for bungalow and upward extensions; the survey turns them into a fixed price for the agreed specification.

Bungalow and upward extensions	Guide price incl. VAT
Chalet conversion with dormers (total)	£45,000 to £85,000
New first floor, standard specification	£2,200 to £2,800 per m²
New first floor, good specification	£2,800 to £3,300 per m²
New first floor, high specification	£3,300 to £3,800 per m²

Do you need permission for an upward extension in Hertfordshire?

Projects in England go through two separate checks. Planning (or confirmation that the work is permitted development) comes from the district, borough or unitary council, and building regulations approval comes from the council’s building control team or a registered building control approver. Where work touches a shared wall or digs near a neighbour’s foundations, the Party Wall etc. Act 1996 applies.

In England, Class AA permitted development allows an extra storey on many detached and semi-detached houses built between July 1948 and October 2018, subject to a prior approval application covering design, neighbours’ amenity and other matters. Houses in conservation areas and other protected land need full planning permission, as do most chalet conversions with front dormers.

What should I think about before starting?

The staircase takes space from the ground floor plan.
Neighbours’ light and privacy are the main planning tests.

What are the steps?

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.
Design and fixed price. You get drawings and a written price for the agreed specification before anything is ordered.
Construction and completion. One site lead co-ordinates every trade through to the building control certificate.

What people ask before starting

Can I add a first floor to my bungalow?

Often yes, if the walls and foundations can carry the load and planning allows. We check the structure first.

How much does it cost to add a storey?

Around £2,200 to £3,800 per square metre of new floor including VAT, or £45,000 to £85,000 for a chalet conversion with dormers.

Do you work in Hertfordshire?

Yes. Hertfordshire is within our coverage for bungalow and upward extensions, along with nearby Watford and Hemel Hempstead.

Also covering

Learn more about bungalow and upward extensions, or see every project we cover in Hertfordshire.