What does the construction year tell you about a house?

What is the ‘original construction year’?

In the BAG, the original construction year (oorspronkelijk bouwjaar) is the year in which the building was completed. Later alterations or a renovation do not change that year. For some old buildings, the construction year is an estimate by the municipality.

Construction periods in broad terms

• Before 1945: often solid walls or early cavity walls, with little or no insulation. In peat areas and the west of the country, frequently a timber pile foundation.
• 1945 – 1975: post-war reconstruction and system building, with many walk-up flats and terraced houses; insulation was still limited.
• 1975 – 1992: after the oil crisis, insulation requirements were introduced; cavity walls were increasingly insulated and double glazing became standard.
• After 1992: the Building Decree (Bouwbesluit) set national requirements for insulation and ventilation, among other things, which became stricter over the years.

These are broad outlines. A lot may have been altered in an individual home. The energy label and a building survey give a better picture of its current condition.

Construction year and foundations

For homes built before around 1970, a foundation on timber piles or a shallow foundation without piles (‘op staal’) is common in certain regions. That says nothing about the condition of a specific foundation, but it is a reason to ask about it. Read more in Foundation problems: what to look out for.