The question always arrives with a number in front: "how much does a 100-square-metre house cost?". And the honest answer starts by flagging a trap: the price per square metre is not constant. A 200 m² house does not cost twice a 100 m² one. It costs considerably less than twice.
Here are the three full budgets, calculated on the same basis: upper-mid specification, turnkey, serviced plot with a gentle slope, taxes excluded and then added.
Why the square metre gets cheaper as the house grows
Because some items do not grow with floor area. The kitchen has the same appliances at 100 as at 200 m². Bathrooms may go from one to two, not from one to four. The water connection costs what it costs. Design and site supervision grow, but not proportionally. Foundations and roof do grow, but they are the items that absorb size best.
The result, measured on real budgets for this construction system:
| Floor area | Turnkey build | €/m² of build | Total, everything in | Real €/m² |
|---|---|---|---|---|
| 100 m² | €215,000 | €2,150 | €272,000 | €2,720 |
| 150 m² | €292,500 | €1,950 | €366,000 | €2,440 |
| 200 m² | €370,000 | €1,850 | €459,000 | €2,295 |
The column that matters is the last one. And the lesson: doubling the floor area does not double the budget, it multiplies it by 1.69.
The breakdown, item by item
100 m² house — €272,000 excluding the plot
- Turnkey build at €2,150/m²: €215,000
- 10 % VAT on the build: €21,500
- Design and site supervision: €17,500 plus VAT
- Geotechnical and topographic surveys: €1,600
- Permit and construction tax (3.5 % + 1 % of material execution): €8,100
- Water, power and drainage connections: €5,000
A well-resolved 100 m² house is three bedrooms, two bathrooms, a living-kitchen and a porch. It is the size where every decision shows most: here one extra bathroom or a badly resolved metre of corridor eats the budget.
150 m² house — €366,000 excluding the plot
- Turnkey build at €1,950/m²: €292,500
- 10 % VAT: €29,250
- Design and supervision: €23,400 plus VAT
- Surveys: €1,800
- Permit and construction tax: €11,000
- Connections: €5,500
It is the most requested size in Spain — the real average for approved detached housing is around 190 m², but the median of what gets built to order sits very close to 150. It allows four bedrooms, two or three bathrooms, a study and a generous living area.
200 m² house — €459,000 excluding the plot
- Turnkey build at €1,850/m²: €370,000
- 10 % VAT: €37,000
- Design and supervision: €29,600 plus VAT
- Surveys: €2,000
- Permit and construction tax: €13,900
- Connections: €6,500
From here the house usually grows over two floors, and that makes it cheaper: less roof and less foundation per built square metre.
What these figures do not include
Worth writing down before signing anything:
- The plot. Between 15 % and 40 % of the total depending on the province, plus transfer tax or VAT, notary and land registry.
- External works: fencing, access, garden, irrigation.
- Pool: €25,000 to €60,000 depending on type and size.
- Earthworks and retaining walls if the plot has a steep slope.
- Loose furniture — fitted furniture is included — and appliances not named in the specification.
How to compare three quotes without getting it wrong
The usual mistake is comparing prices per metre. Three better questions:
- Does the specification carry brands and models? If an item says "top-quality aluminium windows" and does not say which profile, it is not priced: it is estimated.
- Is VAT in or out? 10 % on the build is tens of thousands of euros.
- What happens with variations? A closed budget that does not say how changes are valued is not a closed budget.
For the full breakdown of the nine items in a budget, see the guide on what it costs to build a house in Spain. And if what worries you is how all this is paid for, the self-build mortgage guide explains how a bank finances it.
Frequently asked questions
How much does it cost to build a 100 m² house in Spain?
Around €272,000 with everything included except the plot: build, VAT, design, site supervision, permit, municipal taxes and connections. The build alone is around €215,000.
And a 150 m² one?
Around €366,000 excluding the plot, which is roughly €2,440 per square metre in real terms. The build alone comes to about €292,500.
Is it cheaper to build on one floor or two?
Two. For the same floor area, two storeys spread the same foundation and the same roof over twice the surface, and that cuts the cost per metre by 5 % to 10 %.
How much is a square metre of a timber house?
The same range as a conventional house of equivalent quality: €1,850 to €2,150/m² of build depending on size, and €2,300 to €2,700/m² in real terms with taxes and fees.
Do these prices include the kitchen?
Yes, full kitchen with appliances and fitted wardrobes. It is written item by item in our specification document: it is the check we recommend on any offer.
Ask for yours, on your plot
These three budgets are for getting your bearings, not for deciding. The number that matters comes from your actual plot, its slope, its connections and what the planning rules allow. We give it to you in the first meeting: write to us or book a meeting.
