Patent ID: 7981335

Claim:
A method for the manufacture of a concrete roof tile comprising the steps of: a) admixing a cementitious composition comprising: water, sand, pigment, reactive fine filler, cement and additives; characterized in that in step a): a1) the water, sand, pigment, reactive fine filler, cement and an air entraining agent are mixed under atmospheric pressure; and, a2) a super-plasticiser is then added to the cementitious composition, which is thereafter mixed in a second step in a partial vacuum; b) feeding the mixed cementitious composition into a reusable mold to form green-state roof tile; c) curing the green-state roof tile in a curing station; d) de-molding the cured roof tile, e) conveying the cured roof tile through a surface preparation zone where the upper surface, in use, of the roof tile is prepared to facilitate subsequent application thereto of a surface coating; f) conveying the cured roof tile through a coating zone where the cured building roof tile is provided with a surface coating on its prepared upper surface, and g) the surface preparation of said upper surface includes the application of a primer coat thereto.