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 St Helens?
In St Helens, a wraparound extension typically costs £2,050–£3,000 per m² of floor area, including VAT at 20% (standard rate). For a typical 28 m² project that is roughly £57,500–£84,000. We start from a UK-wide guide and adjust it for the North West, where labour and materials are typically about 6% below average. Design, structural calculations and council fees are extra.
| Size or type | Guide range |
|---|---|
| Smaller project (20 m²) | £41,000–£60,000 |
| Typical project (28 m²) | £57,500–£84,000 |
| Larger project (39 m²) | £80,000–£117,000 |
| Rate per m² | £2,050–£3,000 |
The biggest cost drivers are:
- Drainage changes
- Total footprint and the amount of glazing
- Steelwork and propping of the existing house
- Party wall surveyor fees for one or both neighbours
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 St Helens?
Before anything is built in St Helens, we confirm which approvals apply in 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
- Removal of internal and external walls
- Building control completion
- Structural engineer’s design for steels and supports
- Party wall notices and surveyor liaison
- Design and planning application
How long does it take?
Expect 12 to 18 weeks on site. Allow time beforehand for drawings and approvals, usually 3 to 4 months.
Building in St Helens
Terraced streets across the North West often suit rear dormers and single-storey kitchen extensions.
From WA10 outwards, we take on projects throughout St Helens and the surrounding parts of Merseyside.
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
Approvals
Planning or permitted development confirmation, building regulations and any party wall matters.
- 04
Construction and completion
We build, put right any snags and hand over the building control certificate.
Questions about wraparound extensions in St Helens
How much does a wraparound extension cost in St Helens?
In St Helens, a wraparound extension typically costs £2,050–£3,000 per m² of floor area, including VAT at 20% (standard rate). A typical 28 m² project comes to roughly £57,500–£84,000. 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.
Does a wraparound extension need planning permission?
Almost always. Combining side and rear elements usually goes beyond permitted development limits, so a householder planning application is normally made.
How long does a wraparound extension take in St Helens?
Typically 12 to 18 weeks on site. Design and approvals beforehand usually take 3 to 4 months.
Can we keep a separate living room?
Yes. Many clients keep the front room separate and open up only the back of the house.