Measuring Basements According to NEN 2580

Measuring basements under NEN 2580 might seem straightforward, but there are specific rules that must be followed. Basements can be classified as either “usable residential area” or “other internal space,” depending on accessibility, height, and intended use. Let’s break down these rules step by step.

1. Accessibility

To be included in the usable floor area, a basement must be accessible to people. Crawl spaces, technical recesses, or other inaccessible parts of a basement are not measured. A space where you can normally walk and use the floor area is included.

2. Height Requirements

The net height of the basement determines its classification:

• Net height < 2 meters: The basement is categorized as “other internal space” because it is unsuitable for regular use.
• Net height ≥ 2 meters: A basement with a net height of 2 meters or more can qualify as usable residential area if it meets other criteria, such as insulation and climate control.

3. Daylight and Window Wells

A basement with a window well (koekoek) can be counted as residential area, but only if the well has a minimum height of 2 meters and a floor area of 4 m² or more. Smaller window wells or windowsills are excluded from the calculation.

4. Intended Use

If the basement is only suitable for storage, it will be classified as “other internal space.” However, a basement designed and equipped as a living or hobby room can count as residential area if it meets all structural criteria.

By carefully applying these rules, you can ensure an accurate calculation of the usable floor area in basements.

Explainer Video: How to Calculate Living Area and Other Areas
Would you like to quickly and easily learn how to calculate the living area and other surface areas of a home? Watch this video!