Earth House - Structural Engineering

Structural Engineering

Structures, which are designed as integral arches, can be constructed as stiff individual objects or by means of a sprayed concrete procedure. Arches made of sprayed concrete provide for free and organic shapes, allowing rooms to become suffused with light. The sprayed concrete procedure was first used by natural scientist Carl Akeley in 1911. Akeley patented a device able to spray fine-grained concrete. While sprayed concrete is mainly applied in underground engineering and tunnel construction, Friedrich Kiesler was the first to use this technique for the construction of buildings. Swiss architect Peter Vetsch improved the technique over several years. To date, he has built over 40 earth houses using sprayed concrete, and he can therefore be considered the leading authority in this area of expertise. The sprayed concrete is applied to a finely meshed metal stretch net which is welded onto the supporting armature. The curvatures are bent and formed according to the intended shape of the building. A 20 cm thick polyurethane solid-foam-insulation is sprayed onto the outside of the arches, protecting the house from low or high temperatures. A fleece filter mat is then laid on top of this and the building is covered with a thick layer of soil some 80 cm to 3 metres thick. The foundation of the buildings designed by Peter Vetsch are built conventionally. The interior walls of an earth house are furnished using loam rendering which provides superior humidity compensation. The loam rendering is finally coated with lime-white cement paint.