Asphalt Shingle with Lightweight Structural Aggregate and Method for Making Same

A shingle, comprising:

• a. a reinforcing mat layer that includes an organic fabric that is saturated with asphalt;
• b. a granule-asphalt layer, disposed on top of the mat layer, that includes a plurality of structural-grade lightweight aggregate granules that are suspended in asphalt;
• c. an exterior layer of structural-grade lightweight aggregate granules disposed on top of the asphalt layer;
• and
• d. a structural-grade lightweight aggregate lubricating dust applied to the bottom side of the shingle.

A method of making a roofing shingle, comprising the steps of:

• a. heating a mineral composition to a preselected temperature for an amount of time sufficient to cause the mineral composition to fuse, thereby generating a fused and expanded mineral composition;
• b. milling the fused and expanded mineral composition so as to form lightweight structural-grade aggregate granules;
• c. depositing a layer of asphalt onto a top surface of a reinforcing mat layer;
• d. applying a layer of the structural-grade lightweight aggregate granules onto the layer of asphalt;
• e. pressing the layer of the structural-grade lightweight aggregate granules into the layer of asphalt;
• f. applying an adhesive asphalt strip onto the layer of structural-grade lightweight aggregate granules;
• g. grinding a selected amount of fused and expanded mineral composition into a lightweight aggregate pulverized dust;
• and
• h. applying the lightweight aggregate pulverized dust to a bottom surface of the mat layer.