Almost every conversation about a new house arrives sooner or later at the same sentence: "I heard people are building for such and such per square metre." The figure usually comes from a forum, a neighbour, or an article that quotes it to the nearest few euros. And it is almost always unusable. Not because it is too high or too low, but because nobody says what was divided by what. The same house yields three different per-square-metre prices depending on which area you put in the denominator, and three more depending on what you count in the numerator. The result looks like a fact, when it is the ratio of two undefined numbers.
Let me say the unwelcome part immediately: this article contains no table of euros per square metre. Not because it is a trade secret, but because any figure I wrote here without knowing your plot, the size and shape of your house and the standard of finish you want would be an invention shaped like a fact. That is exactly what most pages answering this question do, which is why their numbers disagree with each other. I would rather show you how to arrive at your own figure. That is the only one worth anything.
Which area are you actually dividing by
The first thing nobody states is the definition of area. At least three are in common use and they give materially different answers for the same house:
- Gross external floor area, measured to the outer face of the external walls, counting every storey, the structure itself, the stairs and the garage. It is the largest number, so it produces the lowest price per square metre.
- Usable floor area, the sum of room areas measured between finished surfaces. It is smaller, because the walls drop out, so the price per square metre rises automatically.
- Heated or living area, which excludes the garage, the plant room, terraces and unheated storage. It is the smallest, and gives the highest price per square metre.
For an ordinary family house with a garage, the gap between the first and the third definition is substantial. If two contractors use different definitions, their figures cannot be compared even if they are building the identical house for identical money. So the first question to anyone who quotes a rate per square metre is always the same: per which area.
What the figure usually contains and what it almost never does
The second problem is scope of supply. The word "house" means something different to everyone, and the boundary tends to sit wherever it suits the person quoting.
| Item | Included in a quoted rate? | Note |
|---|---|---|
| Structure and roof | Almost always | The core of every offer; only the execution differs. |
| Windows, doors, insulation, facade | Usually | If not, the price is for a shell, not for a house. |
| Services, heating, ventilation, electrics | Often | The heat source and heat recovery are frequently carved out. |
| Finishes, tiling, flooring, sanitaryware | Unreliably | The most common place for an offer to stay silent. |
| Kitchen and fitted joinery | Almost never | Yet it is one of the most expensive interior items. |
| The plot | Never | And its price varies between locations more than the building does. |
| Utility connections and the work to build them | Almost never | Driven by distance to the mains, not by the size of the house. |
| Groundworks, retaining, drainage | Rarely | On a slope or in groundwater this is a chapter of its own. |
| Paving, driveway, fencing, landscaping | Almost never | Typically the unpleasant surprise at the end of the job. |
| Design, approvals, site supervision | Never | A different supply, from a different supplier. |
| Tax and contingency | Unclear | Always confirm whether the sum is stated with or without tax. |
Walk that list through an actual offer and you usually discover you have been comparing a weathertight shell against a house ready to move into. The difference is not in how good the firms are, but in where they drew the line.
Why a small house costs more per square metre than a large one
This surprises most people. A smaller house costs less in total but more per square metre. The reason is simple: the expensive parts of a house do not shrink in proportion to the floor area. The kitchen, the bathrooms, the plant room with the heat source, the entrance, the stairs and the services core are nearly as demanding in a house of 110 square metres as in one of 180. Divide their cost across fewer metres and each metre carries more.
The same logic applies to foundations and the roof. Halve the house and neither the roof area nor the foundation structure halves, because what changes is the footprint, not the number of layers and details. So when someone defends a rate by saying they saw it on a bigger house, they are comparing things that are not comparable.
Geometry decides more than it appears to
At the same floor area, two houses can need materially different quantities of material and labour. What governs this is the building compactness factor, the ratio of envelope area to heated volume. A compact two-storey house on a simple rectangular footprint has less roof, less foundation and less facade than a sprawling bungalow with the same usable area. Less envelope means less material, fewer details, less scaffolding, fewer thermal bridges and lower running costs later.
Roof complexity adds to it. Every change of direction, valley, dormer and penetration is craft work with a flashing detail that cannot be rushed. Two houses of identical area, one under a single roof plane and one under an articulated assembly, will never carry a comparable rate per square metre, even if the same person builds both from the same materials.
Standard of finish: the widest spread of all
Clients who assume the structure decides the price are mistaken. The structural system and the envelope have a sensible range; what you put inside the house does not. The same shell can be completed very plainly or very richly, and the gap between those two ends is wider than the gap between any two structural solutions. It runs through windows and shading, floors and tiling, sanitaryware and taps, the heat source and ventilation, fitted joinery, lighting, and how precisely everything is to be set out.
The practical consequence: a rate per square metre that someone quotes is above all a statement about their standard of finish, not about the market. That is why two honest figures can differ several times over without anyone lying.
Region, access and programme
Labour prices are not uniform across Slovakia, and the difference between a regional city and a rural district shows up in every trade item. Add the accessibility of the plot: a narrow approach with no room for a crane or a mixer truck, a slope, rock subsoil, a high water table or a long run to the mains are costs with no relation whatsoever to the size of the house. This is precisely why utility connections can never be estimated from square metres. Programme matters too: a build pushed into a short schedule or into the wrong season costs more than the same build with time in hand.
What moves the number most
| Driver | How strongly it moves the rate | When you decide it |
|---|---|---|
| Standard of finish and equipment | Strongest of all | Continuously, from concept through to purchases on site |
| Scope of supply (where "the house" ends) | Very strongly | When setting the brief for offers, before comparing prices |
| Geometry, compactness and roof | Strongly | At concept stage; changing it later is expensive |
| Size of the house | Strongly, but in the opposite direction to expectation | At concept stage |
| Plot, subsoil and access | Strongly and unpredictably | Before you buy the plot |
| Building services and heat source | Moderately | Between concept and the technical design |
| Region and trade availability | Mildly to moderately | Before you buy the plot |
| Programme and season | Mildly | When planning the schedule |
Instead of multiplying by metres: an estimate that firms up
A budget is not made from one number at the outset but from three documents that arrive in order, each narrowing the uncertainty of the last.
- An indicative cost estimate is produced with the concept design. It works from volume, structural system and the chosen standard, and its output is a range, not a sum. It exists so you can decide whether the brief fits your frame at all, and so the house can be made smaller or simpler while doing so is still free.
- A bill of quantities is derived from the implementation project. It lists the constructions and works with measured quantities and no prices. Only this document makes offers comparable, because everyone is pricing the same items.
- A contractor's tender is the only real number. It comes from a specific firm pricing that bill of quantities on a specific date, and it is binding to the extent that its basis is binding.
The order of operations follows from that. If all you have is an idea, ask for a range and treat it as a range. If you have a design, ask for an itemised construction budget. Which document appears when is set by the design phases, and the related architect's fee is a subject in itself, which I cover in the guide to what an architect costs.
What to ask when someone quotes you a rate
- Which area is the figure calculated against, and does it include the garage and the plant room?
- Which trades and supplies are inside it, and which are not?
- Is it stated with or without tax?
- Which actual house is it derived from, and what were its shape, size and standard?
- What year is it from, and does it reflect today's material and labour prices?
- What document sits behind it: an estimate, a priced bill of quantities, or a signed contract?
If most of those go unanswered, the figure is not a price. It is an anecdote.