We live on a houseboat, as you might have gleaned by now. It is raised a couple of feet above the water, resting on a carefully designed series of caissons, blocks of high-density polystyrene covered in concrete. It’s a remarkable technology that will in all likelihood provide a great floating foundation for our houseboat for fifty to eighty years. The caissons are joined together in a rigid steel grid – a rebar skeleton – that creates a floating platform on which the house rests. The...