On this page
Costs and included work
For prefabricated extension costs, compare the scope first: foundation, opening into the existing building, building envelope and finish level. A price is useful only when supply and finishing work are clearly defined.
| Work / price basis (from) | Starting indication | Scope |
|---|---|---|
| Extension: general budget indication | From € 2,200 per m² | Market indication; specify foundations, structure, finishes and VAT in the quotation. |
Market indications checked on 2 October 2026, not fixed Multi Concurrent tariffs. The stated work and unit apply; the quotation confirms the total, VAT and any additional work.
What affects your total?
Ground conditions, span, glazing, connections to the house and access determine the work. Kitchens, sanitary fittings, building services and interior finishes are included only when specified.
What to send with your request
Send dimensions, photos of the facade and garden, the proposed layout and available drawings. Include your postcode, preferred schedule and the elements that must remain, so the scope can be assessed.
What arrives from the factory?
Confirm whether the supplied elements include frames, insulation, internal finishes or services. Different systems reach site at different stages of completion. Compare written specifications rather than the term “prefab” alone.
Prepare the site
Foundations, the facade opening and any required structural support remain project-specific. Assess the delivery route, crane position and space for installation before committing to production.
Allow for finishing
Ask who completes electrical work, heating, plastering, flooring and decoration. Temporary protection and reinstating the garden or access route should also be identified.
Compare complete budgets
Separate production, transport, lifting, foundations, assembly and finishing. Use the extension cost guide as a general starting point, and confirm the actual scope and VAT in the project quote.