Insulating roof covering permitting snow to melt - by increasing thermal conductivity under snow load

摘要

Material comprises 3 layers (1) a flexible top surface of e.g. polypropylene film with reinforcing filaments; (2) an insulating core 28 cm thick of resilient glass fibre mat; and (3) a rigid base of reinforced plastics. The core compresses under the load of snow and its thermal conductivity increases correspondingly. When the snow load has melted away the core returns to its original thickness and insulating value.