Abstract: A building kit including lightweight, extruded components made of environmentally acceptable, i.e., organic and mineral, materials. The lightweight components are made of: a) untreated chopped straw, grain chaff, rice husks, rock fibers and/or glass fibers, b) binders, namely cement, lime and/or gypsum, and c) mineral additives. The components include air chambers and reinforcing members and are connected using I-beams, adhesives, nails, etc.