To build up a screed coat on a roof surface, a granular expanded inorganic material is subjected to an atomized spray of an adhesive consisting of a solution of waterglass and a hardener therefor so as to form a thin film of adhesive on each grain of the material, and the spray coated granular material...http://www.google.com/patents/US4491608?utm_source=gb-gplus-sharePatent US4491608 - Method for applying a screed coat to a roof surface
