A roofing tile comprising: (a) a substrate comprising: i) sand of a diameter of 4 mm or less; ii) a binder based on Portland cement and (b) a coating disposed on said substrate, said coating resulting from hydration and hardening of a mixture comprising: i) a hydraulic binder comprising at least 35% by weight of alumina, where the hydraulic binder comprises: - at least 60% by weight of a source of calcium aluminate comprising a calcium aluminate cement having an alumina content higher than 35%, and - no more than 1% by weight of sulfate, - less than 50 parts by weight of fly ash for 100 parts of calcium aluminate cement or 20-50 parts of other pozzolanic material having an alumina content of at least 20% by weight for 100 parts of calcium aluminate cement, ii) 50-200 parts by weight of sand for 100 parts of calcium aluminate cement; where the sand has a grading of 0.6 mm or less; iii) less than 10 parts by weight of fine limestone filler for 100 parts of calcium aluminate cement; iv) less than 6 parts by weight of pigment for 100 parts of calcium aluminate cement; v) less than 1.5 parts by weight of superplasticizer for 100 parts of calcium aluminate cement; vi) less than 1.5 parts by weight of rheology modifier for 100 parts of calcium aluminate cement; vii) less than 0.3 parts by weight of retarder for 100 parts of calcium aluminate cement; viii) less than 0.3 parts by weight of defoamer for 100 parts of calcium aluminate cement; ix) less than 0.2 parts by weight of thickener for 100 parts of calcium aluminate cement; the parts of iv)-vii) being expressed in terms of solids contents; and the parts by weight of viii) being expressed in terms of active component; the sulfate content in the mixture not exceeding 1% by weight and wherein the hydration is obtained with a water to calcium aluminate source ratio of less than 0.4. (a) a substrate comprising: i) sand of a diameter of 4 mm or less; ii) a binder based on Portland cement and i) sand of a diameter of 4 mm or less; ii) a binder based on Portland cement and (b) a coating disposed on said substrate, said coating resulting from hydration and hardening of a mixture comprising: i) a hydraulic binder comprising at least 35% by weight of alumina, where the hydraulic binder comprises: - at least 60% by weight of a source of calcium aluminate comprising a calcium aluminate cement having an alumina content higher than 35%, and - no more than 1% by weight of sulfate, - less than 50 parts by weight of fly ash for 100 parts of calcium aluminate cement or 20-50 parts of other pozzolanic material having an alumina content of at least 20% by weight for 100 parts of calcium aluminate cement, ii) 50-200 parts by weight of sand for 100 parts of calcium aluminate cement; where the sand has a grading of 0.6 mm or less; iii) less than 10 parts by weight of fine limestone filler for 100 parts of calcium aluminate cement; iv) less than 6 parts by weight of pigment for 100 parts of calcium aluminate cement; v) less than 1.5 parts by weight of superplasticizer for 100 parts of calcium aluminate cement; vi) less than 1.5 parts by weight of rheology modifier for 100 parts of calcium aluminate cement; vii) less than 0.3 parts by weight of retarder for 100 parts of calcium aluminate cement; viii) less than 0.3 parts by weight of defoamer for 100 parts of calcium aluminate cement; ix) less than 0.2 parts by weight of thickener for 100 parts of calcium aluminate cement; the parts of iv)-vii) being expressed in terms of solids contents; and the parts by weight of viii) being expressed in terms of active component; i) a hydraulic binder comprising at least 35% by weight of alumina, where the hydraulic binder comprises: - at least 60% by weight of a source of calcium aluminate comprising a calcium aluminate cement having an alumina content higher than 35%, and - no more than 1% by weight of sulfate, - less than 50 parts by weight of fly ash for 100 parts of calcium aluminate cement or 20-50 parts of other pozzolanic material having an alumina content of at least 20% by weight for 100 parts of calcium aluminate cement, - at least 60% by weight of a source of calcium aluminate comprising a calcium aluminate cement having an alumina content higher than 35%, and - no more than 1% by weight of sulfate, - less than 50 parts by weight of fly ash for 100 parts of calcium aluminate cement or 20-50 parts of other pozzolanic material having an alumina content of at least 20% by weight for 100 parts of calcium aluminate cement, ii) 50-200 parts by weight of sand for 100 parts of calcium aluminate cement; where the sand has a grading of 0.6 mm or less; iii) less than 10 parts by weight of fine limestone filler for 100 parts of calcium aluminate cement; iv) less than 6 parts by weight of pigment for 100 parts of calcium aluminate cement; v) less than 1.5 parts by weight of superplasticizer for 100 parts of calcium aluminate cement; vi) less than 1.5 parts by weight of rheology modifier for 100 parts of calcium aluminate cement; vii) less than 0.3 parts by weight of retarder for 100 parts of calcium aluminate cement; viii) less than 0.3 parts by weight of defoamer for 100 parts of calcium aluminate cement; ix) less than 0.2 parts by weight of thickener for 100 parts of calcium aluminate cement;