Yes, in the usual ‘warm roof’ configuration, Dryseal can be laid over most rigid polyisocyanurate (PIR) flat roof insulation board with a vapour control layer underneath to provide a Thermal Performance or ‘U’ value which complies with Building Regulations and Green Deal requirements. We recommend that our contractors are certified to Competent Roofer standard to help simplify Local Authority Building Control reporting procedures and benefit the customer.