Flat lintels are an often used and effective method of bridging over wall openings. They consist of a composite system of tension chord and the overlying masonry, which is only considered in regulations in this combined construction. The special features of the construction and design are explained in the present article through the example of aerated concrete flat lintels, with the verification of loadbearing capacity being described and explained based on the latest regulations in technical approvals taking into account the relevant European structural design codes and their national annexes.