Abstract: A solar roof for providing air heated by solar energy to the interior of a prefabricated building of the type having a relatively low pitched roof structure formed by a plurality of interlocking ribbed roof panels. A solar radiation transmissive glazing is attached between the roof panel ribs or other support members to form air passageways. A duct-like inlet plenum communicates with the inlet of each passageway for selectively directing air from inside or outside of the building passageways. A duct-like exhaust plenum communicates with the outlet of each passageway for directing heated air to the building interior. The roof surface may be provided with a darkened coating to increase the absorptivity of the surface and increase the collecting efficiency. The glazing material may be thin flexible solar radiation transmissive sheets or relatively rigid panels of solar radiation transmissive material.