Abstract: A process for producing lightweight, panel or block-shaped gypsum building materials with a pore structure, in particular wall panels, wherein calcium sulphate alpha-hemihydrate, water in a slightly more than stoichiometric quantity, setting retarders and/or accelerators and additives are mixed to form a pourable suspension and subjected to suitable forming. The ground calcium sulphate alpha-hemihydrate, having a Blaine specific surface area greater than 2000 cm.sup.2 /g, is combined if appropriate, with calcium sulphate beta-hemihydrate in a quantity of up to about 30% by weight relative to the calcium sulphate alpha-hemihydrate, and mixed before forming with a surfactant foam of a defined apparent density in the range from 40 to 80 kg/m.sup.3 and a uniform defined pore size, in a quantity for adjusting the apparent density of the gypsum building material to a defined value in the range from 300 to 1200 kg/m.sup.3.