Kitchen Extension Cost in Portsmouth: 2026 Price Guide
30 Jul 2026
Portsmouth is England's only island city, built on Portsea Island, and that geography has shaped its housing more directly than almost anywhere else in the country - with nowhere to sprawl outward, the Victorian terraces packed across Southsea, Fratton and Landport are some of the tightest and most densely built in southern England, with noticeably smaller plots than a comparable city with room to expand.
| Extension size | Typical cost | Notes |
|---|---|---|
| Small (up to 15m²) | £18,000-£31,000 | Common across the island's terraces |
| Medium (15-25m²) | £31,000-£49,000 | Typical rear extension |
| Large (25m²+) | £49,000+ | Rare given typical plot sizes |
Why plot size dominates every Portsmouth quote
Because the city is physically confined to Portsea Island (plus Portsmouth's mainland districts like Cosham and Drayton), Victorian and Edwardian developers packed housing in tightly across Southsea, Fratton and Landport, leaving many rear gardens genuinely small by national standards. A "large" extension in Portsmouth terms is often what would be a medium extension elsewhere, simply because there's less garden to build into before hitting the boundary.
Southsea's conservation areas, which cover a significant share of the city's most desirable Victorian and Regency-influenced streets, add materials and roofline scrutiny on top of the space constraint - worth checking your property's status with Portsmouth City Council before finalising a design.
What's actually driving the price
- Plot size. The island's tight Victorian plots mean garden space, not budget, is often the real limit on how large an extension can be.
- Access. Narrow terraced streets across Fratton and Landport typically have no side access, meaning materials and spoil go through the house.
- Foundations. Much of the island's housing was built quickly to accommodate the naval workforce, on shallower footings than current standards require.
Frequently asked
Do I need planning permission for a rear extension in Portsmouth? Often not if it stays within permitted development limits, though Southsea's conservation area status can restrict this further, and small plot sizes mean it's easier to exceed the limits than in a city with more garden space. Check with Portsmouth City Council's planning portal first.
How long does a typical Portsmouth kitchen extension take? Around 9-12 weeks for a medium single-storey extension, longer for terraced properties without side access.
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