Roof Insulation 10mm. Benefits of GCS Roof Insulation The insulation adds more lifespan to your ceiling system. For example it can protect a gypsum ceiling from cracking due to excessive heat within the roof. GCS roof Insulation foam is a product made of many tiny closed cell globules sealed off from each other. Polyethylene foam is an excellent heat insulation. GCS roof Insulation protects your roof space from heat build-up due to radiant heat penetration. PE roof insulation acts as a heat barrier and protects all services within the roof from drying out, cracking and degrading due to UV radiation. GCS Roof Insulation is a cost-effective insulation that is suitable for use in metal deck roofing system in residential, commercial, industrial and horticultural buildings where temperature variations