2026 Build Costs per Square Metre in Southampton (SO14, SO15, SO16, SO17, SO18)
With moving and stamp duty costs remaining high in 2026, homeowners across Southampton City Centre, Ocean Village & St Mary's (SO14), Shirley, Freemantle & Central Station (SO15), Bassett, Lordshill & Southampton Common (SO16), Highfield, Portswood & University Campus (SO17) are choosing open-plan kitchen-diner extensions and structural knock-throughs over relocating. In Southampton, single-storey extension build costs currently average £2,375 – £3,400 per m² depending on glazing specification, foundation depth, and roof lantern design.
On Hire Southampton, we currently track 38 verified Builders & Bricklayers serving Southampton with an average customer rating of 4.72★ across 567 verified reviews (including local specialists such as Bargate, Travis Perkins, MJH Builders Hampshire Limited). Comparing three itemized quotes from vetted local pros ensures you lock in fair 2026 London & South East rates and transparent workmanship warranties.
2026 Southampton Extension, Structural Steel & Kitchen Fit-Out Costs
Verified Market Rates| Job / Service Scope | Typical UK Cost Range | Est. Timeframe | Action |
|---|---|---|---|
| Load-Bearing Wall Knock-Through & RSJ Steel Beam (Southampton) | £3,075 – £5,725 | 2–4 Days | |
| Kitchen Installation Labour & Plumbing/Electrical First-Fix | £3,525 – £7,050 | 5–8 Days | |
| Complete Mid-Range Kitchen Supply & Fit (Units, Quartz, Appliances) | £12,650 – £23,100 | 2–3 Weeks | |
| Single-Storey Rear Extension (20m² Shell to Plaster Finish) | £46,200 – £68,200 | 8–12 Weeks | |
| Side-Return Wraparound Kitchen-Diner Extension (30m² Turnkey) | £70,400 – £103,400 | 12–16 Weeks |
Compare Top-Rated Builders & Bricklayers in Southampton (SO14, SO15, SO16, SO17, SO18)
Southampton City Council Permitted Development, Party Wall Agreements & Building Control
Many rear extensions in Southampton qualify for Permitted Development (up to 3m deep on terraced/semi-detached homes or 4m on detached homes, and up to 6m–8m via Prior Approval in qualifying zones outside conservation areas). However, removing an internal load-bearing wall for a kitchen-diner always requires structural engineer steel calculations and Building Regulations (Approved Documents Part L, Part P & Part A) sign-off from Southampton City Council Building Control.
- Local Authority Jurisdiction: Southampton City Council covers planning applications and building control inspections across SO14, SO15, SO16, SO17, SO18.
- Conservation & Heritage Zones: Old Town, Oxford Street, and Bassett Avenue heritage corridors regulate alterations to Regency stucco terraces, maritime brick warehouses, and mature tree-lined plots.
- Written Quotes & Certification: Always ensure your Southampton contractor includes waste disposal, scaffolding (where required), and final compliance certificates in their written quotation.
Southampton City Council Planning Permission & Building Control Rules
Old Town, Oxford Street, and Bassett Avenue heritage corridors regulate alterations to Regency stucco terraces, maritime brick warehouses, and mature tree-lined plots.
Southampton Builders & Bricklayers & Cost Guide FAQs
How much does a 20m² single-storey kitchen extension cost in Southampton?
Do I need a Party Wall Agreement for a rear extension in Southampton?
How should I structure payments with a builder in Southampton?
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Compare free, no-obligation quotes from 38 vetted Builders & Bricklayers covering SO14, SO15, SO16, SO17, SO18 on Hire Southampton.
