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What is a row house under OIB?

In everyday speech, every house in a row is a row house. For the OIB guidelines it is a term with five conditions, and it decides whether the project falls into building class 2. Piloti checks the five conditions one by one against your project.

Definition from the OIB-Richtlinien, Begriffsbestimmungen, May 2023 edition, in our own translation.

In short

Under the OIB definitions, a row house (Reihenhaus) is a building with more than two dwellings or business units built directly against each other, not stacked, separated by a vertical wall, each with no more than 400 m² gross floor area and its own entrance from outside; for the building class, the escape level of each unit is considered separately. Piloti checks the conditions against your project and classifies the building class.

Try it with a real questionChecked: September 2026

Row house (Reihenhaus)

“Building with more than two self-contained dwellings or business units built directly against each other, not arranged one above the other, separated from each other by at least one vertical wall, each with no more than 400 m² gross floor area of the above-ground storeys and each with its own entrance from outside for every dwelling or business unit. For classification into a building class under OIB guideline 2, each dwelling or business unit is to be considered separately with regard to the escape level.”
Own translation of “OIB-Richtlinien, Begriffsbestimmungen, Ausgabe Mai 2023”

How Piloti helps

Piloti checks the conditions of the definition against your project and classifies the building class, with the citation. If a value is missing, such as a unit’s area or the escape level of the highest house, it asks for it. The “Brandschutz” way of working then clarifies the requirements for the walls between the units.

The conditions, read one by one

  • More than two units: a semi-detached pair with two units is not a row house under this definition.
  • Built directly against each other and not stacked: stacked maisonettes do not qualify, even if they look like a row from outside.
  • Separated by at least one vertical wall and self-contained: each unit on its own, not parts of a shared dwelling.
  • No more than 400 m² gross floor area of the above-ground storeys each: a single larger unit costs the whole row its status.
  • Its own entrance from outside for every unit: a shared staircase does not fit the definition.

What this means for the building class

The definition of building class 2 expressly names row houses: with no more than three above-ground storeys, an escape level of no more than 7.00 m and units of no more than 400 m² gross floor area each. Unlike other buildings, what counts is not the total area of the row but the area of each unit.

The escape level is considered separately for each unit. On a slope, a row can therefore contain houses with different escape levels, and whether the row as a whole meets the conditions has to be answered house by house.

Row house is not closed building pattern

Development plans speak of open, semi-detached or closed building patterns. That is state and municipal plot development law and says how one builds to the plot boundary. Whether a building is a row house in the sense of the OIB guidelines is decided by the definition above alone. The two questions have to be settled separately.

Good to know

Piloti takes areas and heights from your documents; the classification remains your decision. It reads the building pattern under the development plan from the plan as soon as it is in the project.

Questions

Is a semi-detached pair a row house?

Not under the OIB definitions: a row house requires more than two units built against each other. A semi-detached pair with two units is therefore classified under the general building class rules.

Which building class is a row house?

With no more than three above-ground storeys, an escape level of no more than 7.00 m and units of no more than 400 m² gross floor area each, it falls into building class 2. If a unit exceeds these values, the classification has to be checked again.

How is the escape level measured for a row house?

Separately for each dwelling or business unit, as the definition expressly says. It is measured as usual from the top of the floor of the highest above-ground storey to the adjoining ground after completion, on average.

What requirements apply to the walls between row houses?

They are in OIB guideline 2 in the edition that applies in the state, depending on the building class. State law can add further requirements, for example on sound insulation under OIB guideline 5.

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