A process for preparing roofing granules includes forming kaolin clay into green granules and sintering the green granules at a temperature of at least 900 degrees Celsius to cure the green granules until the crystalline content of the sintered granules is at least ten percent as determined by x-ray diffraction.

A cement-based tile formed from a mixture comprising: a cement in the range of about 0.1 to 88% by wet weight percent; a secondary material in the range of about 0.1 to 50% by wet weight percent, the secondary material comprising limestone, sand, silica sand, gypsum, silica fume, fumed silica, Plaster of Paris, calcium carbonate, fly ash, slag, rock, or a combination thereof; a reinforcement fiber in the range of about 0.5 to 20% by wet weight percent, the reinforcement fiber comprising cellulose fiber, glass fiber, plastic fiber, polypropylene fiber, polyvinyl alcohol (PVA) fiber, homopolymer acrylic fiber, alkali-resistant fiber, or a combination thereof; a rheology modifying agent in the range of about 0.5 to 10% by wet weight percent; a water in the range of 10 to 60% of a total wet material weight; and wherein the mixture is extruded or molded to form the cement-based tile.

One embodiment can provide a solar roof tile. The solar roof tile can include a front cover, a back cover, one or more photovoltaic structures positioned between the front cover and the back cover, and an optical filter positioned between the front cover and the photovoltaic structures. The optical filter is configured to block light within a predetermined spectral range, thereby preventing the light from reflecting off surfaces of the photovoltaic structures to exit the solar roof tile.

One embodiment can provide a solar roof tile. The solar roof tile can include a front cover, a back cover, one or more photovoltaic structures positioned between the front cover and the back cover, and an optical filter positioned between the front cover and the photovoltaic structures. The optical filter is configured to block light within a predetermined spectral range, thereby preventing the light from reflecting off surfaces of the photovoltaic structures to exit the solar roof tile.

A composition for a cementitious roofing tile, the composition includes a cement binder making up 10% to 20% of a total composition weight; a fine aggregate sand making up 20% to 25% of the total composition weight; an aggregate making up 12% to 20% of the total composition weight; a crushed glass making up 15% to 60% of the total composition weight; an alkali-silica reaction (ASR) suppressant; and a predetermined volume of water; the aggregate is selected from one of perlite, vermiculite, hemp, expanded clay, coco coir, shale and slate; and the fine aggregate sand has an average particle size from a minimum of 1 micron to a maximum size of 2 mm; and the crushed glass has an average particle size that ranges from 1 micron to a maximum of 5 mm.

A composition for a cementitious roofing tile, the composition includes a cement binder making up 10% to 20% of a total composition weight; a fine aggregate sand making up 20% to 25% of the total composition weight; an aggregate making up 12% to 20% of the total composition weight; a crushed glass making up 15% to 60% of the total composition weight; an alkali-silica reaction (ASR) suppressant; and a predetermined volume of water; the aggregate is selected from one of perlite, vermiculite, hemp, expanded clay, coco coir, shale and slate; and the fine aggregate sand has an average particle size from a minimum of 1 micron to a maximum size of 2 mm; and the crushed glass has an average particle size that ranges from 1 micron to a maximum of 5 mm.

One embodiment can provide a solar roof tile. The solar roof tile can include a front cover, a back cover, one or more photovoltaic structures positioned between the front cover and the back cover, and a band-stop optical filter positioned between the front cover and the photovoltaic structures. The band-stop optical filter is configured to block light within a predetermined spectral range, thereby preventing the light from reflecting off surfaces of the photovoltaic structures to exit the solar roof tile.

One embodiment can provide a solar roof tile. The solar roof tile can include a front cover, a back cover, one or more photovoltaic structures positioned between the front cover and the back cover, and a band-stop optical filter positioned between the front cover and the photovoltaic structures. The band-stop optical filter is configured to block light within a predetermined spectral range, thereby preventing the light from reflecting off surfaces of the photovoltaic structures to exit the solar roof tile.

Disclosed herein is a roof ridge or hip covering element comprising a first and a second flat body and comprising a flexible sheet for joining together the first and second flat body.

A roofing system for forming a roof includes a plurality of tiles. Each tile has a frame at a perimeter of the tile, and the frame includes an upstream element, an opposed downstream element, and opposed first and second side elements, thereby bounding a central panel area. Each tile further includes a side trim, a batten, and a ridge cap. When the tiles, side trim, batten, and ridge cap are arranged to form a roof, the batten is secured at a lower edge of the roof and directed upward to receive the downstream elements of the tiles, the side trim is secured at a side edge of the roof and directed laterally to receive one of the first and second side elements of the tiles, and the ridge cap is secured at a ridge of the roof and directed downward to lap over the upstream elements of the tiles.