Abstract: A roofing panel of glass-reinforced plastic (G.R.P.) or sheet metal is stiffened by longitudinal beams on its underside to span one pitch of a pitched roof from eaves to ridge. It has an outer skin and an inner impervious liner spaced therefrom and supported on the stiffening beams so as to form a tunnel open at both ends and extending from the vicinity of the eaves to theline of the roof ridge, where vents to atmosphere are provided in the outer skin. Air is convected upwards through the tunnel due to the heating of the outer skin by radiation from the sun. At the eaves end the tunnel also has an inlet port communicating with the roof space, and a damper controls the air flowing in from outside the building and the air flowing in from the roof space. At the line of the ridge the liner meets and is sealed on the corresponding liner of a counterpart panel on the opposite pitch of the roof so as to maintain the integrity of the convection air circuit in each section of the roof.