Abstract: An easily installable, elongated insulation supporting strap for supporting insulation batts or the like between roof purlins is provided which includes respective male and female connection ends allowing aligned, end-to-end interlocking of a plurality of straps in order to support insulation between respective adjacent purlins and present an aesthetically pleasing roof construction. The straps are also configured for engagement with and support by the purlins, and can be appropriately modified to mate with standard types of metal purlins. In preferred forms the batts are supported in spaced relationship to the roof for creating an insulative dead air space therebetween, and separate roof-engaging insulation can be employed to provide further thermal insulation for the roof.