The office facilities and visitor centre for De Slufter, the worlds's largest dredging sludge depot, have been combined as a single concrete mass suggestive of both an air-raid shelter and a rock formation. Standing at the highest point of the coastal dyke (Slufterdijk), the relatively small building is easily picked out in the vast surroundings. It is entirely of concrete to hold its own in the extreme and aggressive climate of wind, salt and sand. Even the roof and the undulating balcony are of concrete. The insulation package is on the inner side of the building; the windows are set unmediated in a concrete rebate.