Recognising foundation problems before you buy

Why the foundation is the biggest risk

With almost any other defect the rule is: annoying, but manageable. A kitchen costs what it costs, so does a roof. Foundation repair is different, because the amounts are an order of magnitude higher and the work cannot be postponed once it becomes necessary. That is why it pays to look at this before your offer, not after.

When is the risk elevated?

• Built before roughly 1970: in areas with soft soil, large parts of North and South Holland, Utrecht, Friesland, Groningen and Zeeland.
• A timber pile foundation. When the piles fall dry the wood can be attacked by fungi; this is called pile rot.
• A low or strongly fluctuating groundwater level in the area.
• Neighbouring properties where repairs have already been carried out. Foundation problems are rarely limited to one property in a terrace.
• Recent large construction projects or dewatering in the immediate vicinity.

You can research this yourself: municipalities increasingly publish foundation risk maps, and the Dutch knowledge centre for foundation problems (KCAF) maintains national information. Also simply ask the neighbours whether foundation repairs have been done in the street, that is often the fastest route to an honest answer.

Signs in and on the property

• Cracks in facades running diagonally and across several storeys, especially at window corners.
• Doors and windows that stick on one side of the house.
• A sloping floor or visible fall (put a marble down).
• Pulled-away skirting boards or extensions sinking away from the main building.
• A wet or musty crawl space, or conversely a strikingly dry one with a timber foundation.

Important: none of these signs is proof. Old houses have cracks, and not every crack is settlement damage. Conversely, a house with a tidy facade can still have an affected foundation. Treat these signs as a reason to investigate, not as a conclusion.

What surveys exist?

There is an escalating scale:

1. Desk research: year of construction, foundation type, soil map, groundwater level and known reports in the area. Cheap and often informative already.
2. Visual inspection / floor levelling survey: measuring whether and how far the house has settled.
3. Foundation survey with an inspection pit: the foundation is actually exposed and the piles are assessed. This gives certainty and costs accordingly more.

The outcome is usually expressed as a remaining service life: the number of years the foundation is expected to last. That figure is exactly what you need to decide whether you buy, and at what price.

And if repairs are needed?

Foundation repair is disruptive and expensive, but it is not a reason to walk away by definition, certainly not if it is reflected in the price. What you want to know: what is the remaining service life, what is the estimated repair method, and is there a joint approach in the street (which often saves a considerable amount). With an association, this topic should also appear in the MJOP and in the minutes.

The amounts mentioned are indications and vary widely by property, method and region. If you have a concrete suspicion, always seek advice from a foundation specialist.