Sisalation (originally known as Decra Foil) provides a reflective barrier, trapping heat between your Decra Roof and your attic cavity. In the same way, as a mirror reflects light, Sisalation reflects 95% of heat and reduces the flow of heat by as much as 70%. Approximately 60% of the heat in a home is radiated from the roof. Sisalation significantly reduces internal temperatures; dramatically reducing the cost of air conditioning.