How Much Does a House Extension Cost in Edinburgh? [2025 Guide]
When homeowners ask me, “How much will my extension cost?”, the honest answer is: It depends.
But that doesn’t mean you should go in blind — here’s what you really need to know about the true costs of extending your home in Edinburgh, whether you’re in Morningside, Grange, Colinton, Trinity, Bartnon or anywhere else in the city.
Average Build Costs for House Extensions in Edinburgh
In 2025, you can expect the typical build cost for a single-storey rear extension in Edinburgh to range from £3,000 – £4,000 per square metre, including VAT but excluding professional fees, statutory fees, and most finishes.
What does this cover?
This usually includes the construction shell, structure, roof, insulation, windows and doors, plasterwork, and basic electrics/plumbing. Any alteration works to the existing house whether that is upgrading of the existing property or wall removals to gain access to the new extension would be an additional cost.
It does not include your kitchen, bathrooms, flooring, fitted joinery, or landscaping — so you’ll need to budget for these separately.
Rough examples:
Small 20m² kitchen extension → £60,000 – £80,000+ (build cost incl. VAT, excl. finishes)
Larger 35m² open-plan extension → £105,000 – £140,000+ (build cost incl. VAT, excl. finishes)
A two-storey extension usually costs around 50–70% more than a single-storey extension, as you’re adding extra structure, rooms, and finishes.
What Affects the Cost?
No two projects are the same, but here are the biggest factors that affect cost:
Type & age of property — Older stone homes, tenements, and listed buildings often need extra structural work, matching materials, or specialist detailing.
Site conditions & access — Narrow lanes, shared gardens, or tricky access can increase labour costs.
Design & specification — Large glazed doors, vaulted ceilings, or high-quality finishes add cost but can add real value too.
Location & local rules — Many areas like Colinton, Grange, Morningside and Marchmont are conservation areas — so you may have stricter planning and materials requirements.
Other Costs to Factor In
Homeowners often forget to include these:
Professional fees — for your architect, structural engineer, measured surveys and any specialist consultants.
Planning & Building Warrant fees — paid directly to Edinburgh City Council.
Kitchens, bathrooms & finishes — these can easily add £20,000–£50,000+ depending on your choices.
Contingency — always allow at least 10–15% for unexpected discoveries once building work starts.
Does Cost Vary by house type and Area?
Yes — your location and property type can make a big difference.
Grange, Morningside, Marchmont: Conservation areas often require more detailed design and higher-quality finishes.
Colinton, Blackford, Trinity: Larger plots can mean bigger extensions, but older properties may need more structural work.
Leith, Portobello: Tight sites and compact plots can limit size but smart design still adds value.
Key Takeaway
Ballpark build cost in Edinburgh 2025: £3,000 – £4,000 per m² (incl. VAT, excl. professional fees & finishes).
Add extra budget for your kitchen, flooring, landscaping, professional fees and a sensible contingency.
How to Get a Realistic Budget for Your Home
No two extensions are the same — that’s why an early feasibility study is worth its weight in gold.
A good architect will help you:
Develop realistic costs
Navigate planning and conservation requirements
Prioritise what adds real value
Avoid surprises once you’re on site
MDA Studio can arrange for an independent Cost Consultant to provide a cost estimate for the works prior to proceeding with a planning application
Thinking of Extending?
I work with homeowners across Grange, Morningside, Colinton and beyond — helping you design a beautiful, practical extension that truly works for your family and your budget.
Get in touch for a friendly, no-obligation chat about what’s possible