Craftsmanship under the ground

One mistake can have major consequences

Foundation problems are a growing problem in the Netherlands. Aging wooden pile foundations and changing groundwater levels are taking their toll. Repairing these vulnerable foundations requires thoughtful engineering and the controlled handling of risks. “It is precisely at the front end that you make the difference,” suggests Reinder van der Wel of Van Dijk Maasland, who in a recent project managed to save as much as 20 percent by revising the entire foundation plan.

About 90 percent of our projects are in Rotterdam, says Van der Wel. “Based on an extensive inventory, we develop a technically sound plan that is as economically optimal for the customer as possible. We offer this for a fixed price. Only after awarding the contract do we start the further elaboration: structural calculations, drawings and permit applications.”

Special drainage methodology

Foundation repair always involves risks, especially if drainage is involved. In areas with wooden pile foundations, prolonged drying can be detrimental. “Traditional well drilling with vacuum and filters can increase the load on existing, already weakened piles. That's why we use a proprietary method for drainage,” says Van der Wel. “We pull a trench and provide a controlled discharge via a bell pump of the water flowing into the trench. For a deeper trench, we first apply a layer of gravel as drainage, then build up from there. In this way we limit the impact on the groundwater level and minimize risks to adjacent properties.”

Design smarter, execute better

According to Van der Wel, the real difference Van Dijk Maasland makes is at the front end. “By combining the knowledge of both structural engineer and contractor, we often arrive at more efficient plans than traditional designs. For example, we saved as much as 20 percent in one project for a housing association by revising the entire foundation plan, even though the original plan had already been worked out and accepted. We almost always work on a fixed-price basis. That means we bear the risk. That is precisely why we invest heavily in preparation and work transfer.”

Always customized

Infra projects are often cast in traditional RAW specifications; with foundation repair, this is never the case. “We create a thorough plan for each project. And that doesn't always consist of the same solution or the same technique. Sometimes we apply our own pile systems, sometimes just an alternative if it's more efficient,” Van der Wel emphasizes. “And another important issue involved in foundation repair is the execution risks. The old foundation is always in bad shape, but the extent of it you only see after excavation. We are lucky to have experienced professionals who can anticipate unexpected situations and, from Van Dijk Maasland, have access to the right tools that you don't buy in a hardware store.”

Foundation repair is specialized work, that much is clear. “One mistake can have major consequences. So always call in an expert,” Van der Wel advises in conclusion.