Abstract: A system for heating and ventilating a building which includes a generally peripheral foundation element which supports the external walls of the building. Room air is heated and circulated below the floor and up through floor openings at the external wall. A barrier is connected to the foundation wall so as to span the area enclosed by the foundation wall at a level beneath the floor. Exhaust air is conducted to a region beneath the barrier for surface-enlarged contact with the underside of the barrier. The foundation element and/or the base that supports the foundation element is permeable to air along essentially its full length beneath where the foundation element connects with the barrier and exhaust air flows out through the foundation element or its supporting material while effecting an exchange of heat therewith.

Abstract: A web for trusses, trusses with at least one chord including a cast slab and also chords for a slab in a cast member, manufactured from bar, wire or strip material, which like diagonals in a lattice girder are inclined in relation to the longitudinal direction of the chord, fastened to the chords or to the chord and slab, respectively.