Roofing, cladding or siding product, its manufacture and its use as part of a solar energy recovery system

A roofing, cladding, or siding module comprising:

• an underlapping region and an exposed region, wherein the underlapping region is adapted to be substantially covered by the exposed region of an adjacent module when installed on a building surface;
• and
• an outer surface and an under surface, wherein the under surface of the underlapping region is profiled to define a pathway for air flow between the module and the building surface;
• wherein the profile of the under surface of the underlapping region is patterned in a manner to (A) create turbulence in the air flow, or (B) increase the surface area of the module in contact with the passing air flow compared to a module lacking such a surface pattern, or both (A) and (B);
• wherein the profile of the under surface of the underlapping region comprises a plurality of projections extending from said under surface to the actual or a notional plane of the building surface when installed, such that the projections create a tortuous pathway between the module and the actual or the notional plane of the building surface;
• wherein the plurality of projections at least in part define the profile of the under surface of the underlapping region and are arranged to form the pattern thereon;
• wherein at least one of said plurality of projections is defined by a recess in the outer surface of the underlapping region, said recess configured as a fixing region for receipt of a fastener for securing said module to the building surface;
• wherein the entirety or at least a substantial part of the under surface of the underlapping region is patterned;
• and
• wherein the under surface of the exposed region is devoid of projections.