Prodn. of temp.-resistant, highly loadable building material (I) comprises mixing at least 70 (wt.)% coarse and/or finely ground mica with a flake size less than 5 mm, binders and solvent and moulding and drying the mixt. USE/ADVANTAGE - (I) is used for prodn. of fireproof roof bearers and supports, doors and panels and of boats (claimed). (I) has very high tensile, compression and impact strength and very high resistance to temp., acids etc. and is produced from a very cheap starting material, using very small amts. of energy. It is lightweight and anisotropic. The surface properties and self-alignment of the mica flakes under gravitation gives the best thermal insulation property and greatest impact strength in the direction perpendicular to the surface of panels. In contrast to asbestos fibres, mica is not carcinogenic, so that (I) can be recycled without health hazard. Boats made from (I) are resistant to corrosion by sea water.