Foundation is a crisis under our feet: 'Half a million properties at risk'

Cracking facades, subsiding homes and rising repair costs: the foundation problem in the Netherlands is slowly but surely developing into a bigger and bigger problem.

According to figures from the Kennis Centrum Aanpak Funderingsproblem (KCAF) approximately 120,000 homes suffer from foundation damage, representing an estimated repair task of 11 billion euros. And although steps have been taken from the government with the National Program to Address Foundation Problems, broad societal urgency is yet to be seen. "As long as no houses are collapsing, the real political pressure often comes late," says Jaap Estié of the Nederlandse Vereniging Aannemers Funderingswerken (NVAF).

A problem that is slowly getting bigger

According to Frank van Lier, director of the KCAF, the problem threatens to get worse if insufficient action is taken. The KCAF talks about possibly half a million properties at risk over time due to subsidence, drought and falling groundwater levels. "If we do nothing, a huge number of properties are going to have problems," says Van Lier. "But with prevention, you can potentially prevent 30 percent of the damage."

Anyone thinking of foundation problems quickly thinks of old tilting canal-side houses on centuries-old pile foundations eaten away by pile worm. The problem is broader, however, and affects older homes built on wood as well as those founded on steel. That is, without piles, directly on the foundation. The risks are particularly high in parts of North and South Holland, Friesland, Groningen and Rotterdam-Rijnmond due to weak soils and varying groundwater levels.

According to experts, the greatest technical risks are in wooden pile foundations that become dry for long periods of time. At the same time, the greatest number of problem cases are precisely in homes founded on steel, simply because there are more of them. There, uneven subsidence and changing soil conditions cause cracks and subsidence.

According to Estié, moreover, the urgency is often not felt until visible damage occurs. "Many foundations are not addressed until cracks really appear or structural problems become visible. Technically, you should often intervene much earlier."

Capacity falls short

One of the biggest challenges is the limited repair capacity. According to KCAF, about 1,000 properties a year are currently being addressed. This is insufficient, according to Van Lier. "In order to keep the problem manageable, you have to move toward 7,500 properties per year in recovery capacity," he states.

This requires not only more executive capacity, but also more foundation specialists, inspectors, structural engineers and researchers. Both KCAF and NVAF emphasize that training and knowledge development must be scaled up quickly.

There is also a practical problem: foundation repair is technically complex and often drastic for residents. During work, residents regularly have to leave their homes temporarily. Housing corporations in particular run into complicated logistical and financial issues. "You need replacement housing, financing AND residents who want to cooperate," says Estié. "That makes it much more than just a technical problem."

Financing also varies greatly depending on the situation. Corporations have different options than private homeowners, while mixed housing blocks with different owners make decision-making extra complicated. According to Estié, this regularly delays projects by years.

Awareness is slowly growing

In recent years, attention to foundation risks does grow. Since April 1, stricter requirements have applied for appraisers to explicitly include foundation risks in appraisal reports. According to Van Lier, this is an important first step.

As a result, when homes are sold, insight into possible foundation problems arises sooner. Yet, according to him, there is still a lot of uncertainty in the market. For example, an official "foundation label" does not exist. KCAF therefore advocates a national housing passport: a file linked to the home that contains information on foundation, maintenance, asbestos and other construction risks.

"That file should move with the house to a new owner," says Van Lier. "Then you get much more transparency." Experts say better data is crucial. Currently, a complete national picture of foundation risks is still lacking. Municipalities, knowledge institutions and market parties do collect more and more data through quick scans and surveys, but that information is still fragmented.

Insufficient financial room

Even residents often lack a sense of urgency. Reinder van der Wel of foundation specialist Van Dijk Maasland sees this every day in Rotterdam neighborhoods with foundations from the early twentieth century. According to him, the first signs are often visible in the house itself: leaning, recurring cracks and doors or windows that continue to jam, even after repeated touch-ups. Yet many owners wait a long time before intervening.

"Five years of delay between initial suspicion and actual implementation is really no exception," says Van der Wel. "Certainly not when several homeowners share one foundation together."

According to him, especially in vulnerable neighborhoods, there is another, social problem at play. Residents simply do not have enough financial room to pay for costly foundation repair. "Those people sometimes stick their heads in the sand. Not because they don't want to see it, but because they have no alternative," he says. "That's where the government really has a role to play."

Government takes first steps

The government now recognizes the seriousness of the problem through the National Approach to Foundation Problems (NAF). Quartermaster Christel Lange was also appointed to coordinate the approach. Still, stakeholders feel the pace is too slow. According to Van Lier, the current funding is mostly temporary. The national government previously made some 60 to 70 million euros available, but structural funding is still lacking.

According to various estimates, the total repair task is heading toward 11 to 12 billion euros. In addition, experts point to an administrative problem: homeowners remain legally responsible for their foundations, while causes such as groundwater management are often beyond their control. According to them, municipalities and water boards therefore have a much larger role to play than they often do now.

"It is actually not a question of whether the problem will occur, but when," says Van Lier.

According to Van der Wel, moreover, the government needs to start targeting future problem neighborhoods much sooner. He cites examples of Rotterdam neighborhoods where houses have subsided to the point where repair is hardly profitable.

"You have to look now at where the problems will be in 30 years," he says. "Then you can still give residents perspective instead of intervening only when a neighborhood is actually already lost."

Technology is developing rapidly

Within the management of foundation problems, prevention plays a major role. But what exactly does this look like? Examples include active groundwater management, infiltration systems and techniques to limit soil movement. Rotterdam, for example, is experimenting with solutions to better regulate groundwater levels at the neighborhood level.

In addition, new technical innovations for foundation reinforcement and soil improvement are emerging. According to Van der Wel, foundation repair has now become "high-tech work. "Many people still think of foundation repair as simple piling, but in reality it involves complex structures under existing buildings that must remain upright during the work," he says.

Technically, he says, almost anything is possible, provided the repair is properly designed and executed. Modern techniques range from new concrete pile foundations to clever steel structures and customized solutions where existing floors can be preserved.

According to Van Dijk Maasland, smart design adaptations can sometimes reduce the costs of large projects by 20 percent, without concessions to safety or lifespan. "The minimum standard should always be the Building Code," says Van der Wel. "But within those frameworks you can design much smarter than in the past."

A long-term task

The challenge now lies not only in technology, but mainly in organization, financing and awareness. Knowledge and repair methods are developing rapidly, but many neighborhoods are still at the beginning of a long-term approach.

"You have to look ahead," says Van der Wel. "Not wait until a neighborhood really gets into trouble, but rather determine what you will be up against in 20 or 30 years." For the construction industry, that means a growing demand for specialist knowledge, cooperation and preventive measures in the coming years: even before foundation problems become visible.