MATERIALS IN CONTEXT: ROOFING.

Types and systems of roofing materials available in the Arab world are reviewed. Two main areas of technological change accorded emphasis in this review are first, the continuing introduction of more and more versions of single-ply high performance weatherproofing membranes which are greatly simplifying the processes of installing multi-component roofing systems, where secondary structure, thermal insulation, and weatherproofing are separate materials; and second, the use of polyurethane foam as the insulating core of multi-purpose, single-component roofing panels.