The client wanted to create a 21st century country estate," says architect Sander van Schaik, one of the founders of the Rotterdam-based practice De Kort van Schaik, when asked about the design of the House on the Raboes. The plot, located on the banks of the Eemmeer lake, about half an hour west of Amsterdam, is adjacent to a small sailing marina. The area already had a number of architecturally distinct structures as well as a wooden cabin, where the owner liked to spend long summer evenings looking out over the water.
With large doors to reveal the panoramic views and big Dutch skies, it was an idyllic spot. But the cabin was not suited for winter use, and De Kort Van Schaik had to come up with a more robust, year-round solution to give the client a proper home. The accretion of existing structures made fitting in difficult. "In the end, we felt like the building needed to be like a rock, which has landed on site, not something that anchors into the site, but almost loosely lies on the field."
The house's most distinct feature are the rough, board-marked walls made of concrete poured in situ. These solid structures run both internally and externally, forming three rectangular pavilions arranged in a tight, orthogonal cluster. But in situ concrete wasn't actually the architect's first choice of material.
Earlier on in the process, rammed concrete was considered, Van Schaik explains. "Rammed concrete is very tactile, you can see how it has been made and you can feel it and it's different everywhere and it has a certain thickness," he says. "So it's a very honest way of building, an almost traditional way of using concrete."
"Together with the contractor, we started to make a mock up from rammed concrete, and it was just really, really gorgeous," says the architect. "It fit really well in its setting of the reeds and the grass and the clay shores." But the architect and the client were not sure rammed concrete could withstand the wet and frosty winters, so had to lookfor an alternative.
Poured concrete eventually proved to be a suitable work-around, though it involved further experimentation on the contractor's part. At first, they tried a ready mixed concrete, with added die to soften the harsh colours down into a more sympathetic tone. But even this proved too sleek, and did not match the architectural vision. Instead, the architects began to experiment with their own concrete mixes, omitting modern silicone additives that make it easier to remove the moulds, and experimenting with different grades of sand and aggregate. "There's a brown sand from this specific place in Belgium which we added to the concrete to achieve the right colour," explains van Schaik.
One thing that helped facilitate the architect's elaborate search for the perfect material mix was the fact that the client had been a contractor and a developer himself before handing the reins of his company over to his son. "That was perfect because it allowed us to have a very close collaboration," says the architect. It also removed much of the incentive of the contractor to make significant savings by sacrificing build quality during construction.
The results are an impressive melding of quality and sophistication. Despite its solid appearance, the house is actually a double leaf construction with a 120mm gap. Traditional, roughly plastered masonry comprises the inner leaf. This provides space for insulation, but also hides frames for the sliding windows, which, like in the owner's initial smaller cabin, opens its inside completely to the outside to capture the stunning views of the Eemmeer. A roof clad in untreated timber planks echoes the imprints of the boardmarks in the concrete and creates a material continuity.
Inside, the architects also play with transitions between inside and out. The zone between the three pavilions is treated almost as an outside space where the boardmarked concrete walls are carried through. The bedrooms on the other hand, are plastered and whitewashed in a nod to more conventional, and more sheltered domestic interiors. But even within these volumes, the architects have inserted glazed in patios, where walls revert to their rough state, and where skylights flood the space with daylight.
One of these patios has become a bathroom conceived by celebrated, Rotterdam-based industrial designer Sabine Marcelis. Leaving the walls intact, Marcelis clustered all the functions in the center of the room, fashioning a bath, a sink and a shower from freestanding blocks of yellow epoxy resin which sit apart from the building's walls. This space provides a burst of soft colour in the otherwise clean, minimalist interior.
Above all, the house exudes a sense of calm, which feels appropriate in the flat landscape and inland water body over which it captures expansive views. In between the three tectonic volumes of raw concrete, a series of interstitial, highly glazed spaces form moments for everyday living and also blur the lines between indoor and outdoor – a fireplace embedded low in a wall, a skylight beneath which to sit.
The successful use of materials, and the focus on subtle details, down to the exact texture of the concrete, set the project apart. "The concrete is very tactile. You can see how it's made, you can feel it…At first the building's like a monolith, but when you get closer it unfolds and you start to see that the detail is more refined and elaborate.
