Short answer — There is no reliable price per square metre without a site visit: cost depends on the condition of the building, floor area, finish level, share of bespoke work and services to redo. The only sound basis is an itemised quote, line by line, prepared after visiting the site.
The five factors that move the budget
- Condition of the building: sound structure or repairs needed (cracks, damp, roof)?
- Scope: refresh, heavy renovation or full reconfiguration.
- Services: electrics and plumbing kept or redone.
- Finish level: tiling, joinery, kitchen and bathrooms.
- Outdoors: terrace, pool, garden, fencing.
How to read a quote
A good quote separates trades (demolition, structure, services, joinery, finishes, fit-out), states materials with references, lists exclusions and gives a schedule. Beware of a single lump sum with no breakdown: it makes comparison impossible.
How to get a reliable estimate
Prepare photos, plans if you have them, approximate area and the list of desired works, then request a visit. You can also budget in phases: building envelope first, interior next, outdoors last.