Two-storey extensions in St Helens
Homeowners in St Helens can use us for the whole project or just the drawings and approvals. Start with a free visit.
St Helens at a glance
- Postcode districts
- WA9 and WA10
- Area
- Merseyside, England
- Price region
- North West England
- Nearest towns
- Haydock (2.4 miles), Rainhill (2.7 miles), Whiston (3.1 miles), Prescot (3.1 miles)
- Distance to Liverpool
- about 10.4 miles
- Approvals
- Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission.
We cover St Helens (WA9 and WA10) and the places around it, including Haydock (2.4 miles), Rainhill (2.7 miles) and Whiston.
Extensions available in St Helens
Two-storey rear extensions
Guide from £53,000 in St Helens, including VAT.
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Two-storey side extensions
From £82,000 in St Helens. Free visit to firm it up.
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Two-storey wraparound extensions
St Helens guide price from £114,500, Standard spec.
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Part single, part two-storey extensions
From £68,500 in St Helens. Free visit to firm it up.
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Extensions over a garage
Guide from £30,000 in St Helens, including VAT.
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First-floor extensions
Our North West England guide starts at £24,000 for this type.
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Two-storey extensions for semi-detached houses
From £53,000 in St Helens. Free visit to firm it up.
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Two-storey extensions for detached houses
St Helens guide price from £82,000, Standard spec.
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Kitchen extensions with bedrooms above
Design, approvals and build for St Helens homes. Guide from £53,000 (before kitchen units).
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Extra bedroom and en-suite extensions
Guide from £53,000 (plus en-suite) in St Helens, including VAT.
Learn moreWhich type suits your house?
Rear, side, wraparound or over the garage: each adds space in a different way. For most houses in Merseyside, one or two of these will clearly suit the plot better than the rest, and we'll tell you which.
Also available in Merseyside
- Two-storey front extensions
- Two-storey extensions for end-of-terrace houses
- Two-storey annexe extensions
- Garage conversions with a room above
- Two-storey extension plans and drawings
- Planning permission for two-storey extensions
- Structural engineering for two-storey extensions
- Building regulations for two-storey extensions
- Party wall notices for extensions
- Design and build two-storey extensions
Rules for St Helens
St Helens is in England. Two-storey rear: up to 3 m deep and 7 m from the rear boundary under permitted development. Side, wraparound and front: planning permission. Householder planning application: £548 (or £575 for applications made from 8 December 2026). Lawful development certificate: £274 (about £288 for applications from 8 December 2026). Councils should decide householder applications within 8 weeks of validation.
The full England rules explained
Questions about extensions in St Helens
Do you cover St Helens?
Yes. We cover St Helens (WA9 and WA10) and the surrounding area, including Haydock and Rainhill. The first site visit is free.
What does a two-storey extension cost in St Helens?
Using our North West England guide, a two-storey rear extension with a 4 m × 3.5 m footprint on two floors (28 m² of new floor space) is about £53,000–£72,000 including VAT. An extension over a garage is about £30,000–£43,500.
Which other places near St Helens do you cover?
Everywhere around it, including Haydock (2.4 miles), Rainhill (2.7 miles) and Whiston (3.1 miles), and the rest of Merseyside.