ventilated roofs

The following paper is focused on hygrothermal behaviour of roofs with ventilated air layers subjected to air leakages in their internal decks (the internal partial construction located below the ventilated air layer). Possibilities of CFD modelling of such constructions are discussed in the first part of the paper including the problem of introduction of water vapour diffusion into calculation. A brief comparison of results from CFD analysis and from calculation based on a technical standard is also included.

The potential for passive cooling of roof slabs incorporating an air cavity is important with respect tothermal comfort. Roof systems in traditional buildings, incorporated a ventilated roof or an air cavity.The concept has been proposed again in contemporary buildings in the construction of roof slabs,using a modular formwork system, where the cast in situ concrete slab is isolated from the screed with the introduction of a ventilated air space. The cavity is primarily intended to curtail the conduction and inward radiation of heat from the intense solar insolation on the concrete roof.