What is a wraparound extension?
A wraparound extension combines a side return and a rear extension into one L-shaped addition. It gives the largest possible ground floor, often creating an open-plan kitchen, dining and living space across the whole width of the house.
How much does a wraparound extension cost in Hertfordshire?
In Hertfordshire, a wraparound extension typically costs £2,350–£3,400 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £66,000–£95,000. Prices across the East of England are typically 6% above the UK average for this kind of work, which is reflected in the range for Hertfordshire. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £47,000–£68,000 |
| Typical project (28 m²) | £66,000–£95,000 |
| Larger project (39 m²) | £91,500–£132,500 |
| Rate per m² | £2,350–£3,400 |
The biggest cost drivers are:
- Party wall surveyor fees for one or both neighbours
- Access for materials on terraced streets
- Steelwork and propping of the existing house
- Total footprint and the amount of glazing
A guide range is only a starting point: the guide price tool gives an instant figure for your size, and a free survey turns it into a fixed quote.
Do you need planning permission for a wraparound extension in Hertfordshire?
Approvals for a wraparound extension in Hertfordshire follow the rules for England. In England a wraparound extension combines side and rear elements, which normally takes it outside permitted development, so a householder planning application is made.
Building regulations approval comes from the council’s building control service or a registered building control approver. The work is inspected at key stages, such as foundations, drainage and insulation, and a completion certificate is issued at the end.
If the answer is not clear-cut, we can apply for formal confirmation before you commit to the build.
What we handle
From survey to sign-off, the job normally involves:
- Underfloor heating option, electrics and plastering
- Party wall notices and surveyor liaison
- Structural engineer’s design for steels and supports
- Removal of internal and external walls
- Walls, roof and glazing
- Building control completion
How long does it take?
The build itself usually takes 12 to 18 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in Hertfordshire
Many towns in the East of England have estates built since the 1970s, where garage conversions and rear extensions are popular.
Towns we cover in Hertfordshire include Watford, Hemel Hempstead, Stevenage, St Albans, Welwyn Garden City and Cheshunt.
How it works
- 01
Visit and measured survey
A free visit to understand the project, check access and take measurements.
- 02
Drawings and written quote
We prepare the design and give you a written, itemised quote with inclusions and exclusions.
- 03
Permissions sorted
Applications, building control and neighbour arrangements, all before the start date.
- 04
Build and handover
Work follows the agreed programme, with inspections along the way and a completion certificate at the end.
Questions about wraparound extensions in Hertfordshire
Will both neighbours be affected?
Usually only the neighbour on the side return side, but rear foundations near either boundary can trigger party wall notices.
How long does it take to build?
Around 12 to 18 weeks on site after approvals. Design, planning and party wall matters usually take 3 to 4 months beforehand.
Do you build wraparound extensions in Hertfordshire?
Yes. We build wraparound extensions across Hertfordshire, including postcodes AL1, AL10, AL2, AL3 and AL4. Every project starts with a free home visit.
How much does a wraparound extension cost in Hertfordshire?
In Hertfordshire, a wraparound extension typically costs £2,350–£3,400 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £66,000–£95,000. Your fixed price depends on the survey and drawings.
What about the old back addition?
The side wall of the back addition is usually removed and replaced with a steel beam, so the old kitchen joins the new space.