Two-storey extensions in Southsea
We design, get approval for and build two-storey extensions in Southsea and the surrounding area. Choose the type of extension below or book a free site visit.
Southsea at a glance
- Postcode districts
- PO4 and PO5
- Area
- Hampshire, England
- Price region
- South East England
- Nearest towns
- Portsmouth (1.1 miles), Gosport (1.9 miles), Cosham (4.5 miles), South Hayling (5 miles)
- Distance to Southampton
- about 16 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 Southsea (PO4 and PO5) and the places around it, including Portsmouth (1.1 miles), Gosport (1.9 miles) and Cosham.
Extensions available in Southsea
Two-storey rear extensions
For homes in Southsea: typical guide from £61,500.
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Two-storey side extensions
From £94,500 in Southsea. Free visit to firm it up.
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Two-storey wraparound extensions
Design, approvals and build for Southsea homes. Guide from £132,500.
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Part single, part two-storey extensions
Design, approvals and build for Southsea homes. Guide from £79,000.
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Extensions over a garage
For homes in Southsea: typical guide from £34,500.
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First-floor extensions
Design, approvals and build for Southsea homes. Guide from £27,500.
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Two-storey extensions for semi-detached houses
From £61,500 in Southsea. Free visit to firm it up.
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Two-storey extensions for detached houses
Design, approvals and build for Southsea homes. Guide from £94,500.
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Kitchen extensions with bedrooms above
Our South East England guide starts at £61,500 (before kitchen units) for this type.
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Extra bedroom and en-suite extensions
Guide from £61,500 (plus en-suite) in Southsea, including VAT.
Learn moreWhich type suits your house?
If you're not sure which type fits, that's what the free visit is for. We'll sketch the realistic options for your house in Southsea, with a rough idea of the approval route and cost for each.
Also available in Hampshire
- 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 Southsea
Southsea 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 Southsea
Do you cover Southsea?
Yes. We cover Southsea (PO4 and PO5) and the surrounding area, including Portsmouth and Gosport. The first site visit is free.
What does a two-storey extension cost in Southsea?
Using our South East 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 £61,500–£83,000 including VAT. An extension over a garage is about £34,500–£50,500.
Which other places near Southsea do you cover?
Everywhere around it, including Portsmouth (1.1 miles), Gosport (1.9 miles) and Cosham (4.5 miles), and the rest of Hampshire.