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House Extension Cost Guide — Manchester
A straightforward breakdown of what a house extension actually costs in Manchester and the North West, what changes the price, and how to budget before you get a formal quote.
Typical Costs
What does a house extension cost?
Single-storey extension
£2,500–£3,000
per m², standard finish
Double-storey extension
£2,200–£2,700
per m², standard finish
Wraparound / side return
£2,700–£3,200
per m², standard finish
What changes the price
- Size & footprint Larger extensions cost more in total but the price per m² usually drops slightly, since groundworks and roof structure don't scale exactly with floor area.
- Structural complexity Removing load-bearing walls, steel beams, and working around existing drainage or foundations all add cost before any finishing work starts.
- Finish level Standard fittings vs. bespoke joinery, underfloor heating, bi-fold or sliding glass doors, and higher-spec kitchens can shift the total significantly.
- Planning route Permitted Development is faster and cheaper than full planning permission — projects needing a full application carry extra time and fees.
- Site access Restricted access, shared driveways, or working in a terrace can increase labour time and material handling costs.
- Party wall notices Side-return and wraparound extensions often run along a shared boundary, which can trigger a Party Wall etc. Act notice — check with our free Party Wall Checker before finalising your budget or timeline.
These are indicative estimates for budgeting purposes, not a fixed quote, and exclude VAT and professional fees (architect, structural engineer, Building Regulations). Final pricing depends on the drawings and full scope of works agreed for your specific project, and can vary from these ranges once a site visit and detailed design are complete — get in touch for a detailed, itemised quote.
Common Questions
House extension costs, explained
No — these are indicative ranges to help you budget before speaking to us. Your actual price depends on the specifics of your project, and we always provide a detailed, itemised written quote after a site visit, not a generic estimate.
Yes — planning and Building Regulations costs, where required, are itemised separately in your written quote rather than hidden inside the build cost, so you can see exactly what you're paying for. Not sure if your project needs planning permission at all? Our free Planning Permission Checker gives an indicative answer in under two minutes.
Furniture, most appliances, and external landscaping beyond the immediate build area are typically excluded unless specifically requested and priced in. VAT and professional fees (architect, structural engineer, Building Regulations) also sit outside the core build cost — see the note below the cost table above.
Staying within Permitted Development limits avoids planning application time and fees, keeping the design simple (avoiding complex rooflines or structural changes) reduces labour cost, and agreeing the full specification before work starts avoids costly mid-project changes.
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Areas We Cover
Based in Manchester, working across the wider North West on design & build, windows & doors, and networks & security projects.
- Manchester
- Salford
- Stockport
- Trafford
- Bolton
- Bury
- Oldham
- Rochdale
- Warrington
- Cheshire