Roofing systems are one of the most important and largest expenditures that building owners can make. This significant investment over the life of the building typically includes the roof deck, waterproofing membrane, insulation, installation, maintenance and repair. Contractors and architects are increasingly finding that roofing systems using expanded polystyrene (EPS) can meet the needs of the most demanding building requirements. EPS roofing insulation can be used in most roofing systems and is capable of providing cost effective and consistent thermal performance.
EPS offers measurable energy savings, long-term R-value , effective water resistance, dimensional stability and strength when properly installed and protected from moisture. These systems may include flat and/or tapered foam insulation for use in traditional built-up assemblies and most single ply membrane systems.
EPS roof insulation may be reused in some roofing applications following inspection to ensure its physical properties have not deteriorated from unseen conditions. EPS insulation is available from regional producers, roofing material distributors and building supply centers.
There are regional building codes that dictate the requirements for foam plastics used in building construction. EPS resin suppliers and roof insulation manufacturers are listed under Underwriters Laboratories Inc. and participate in quality assurance programs to ensure that both the resins used to manufacturer EPS insulation and the foam insulation produced from those resins meet the surface burning requirements of the model building codes when tested in accordance with UL 723 (ASTM E 84) Steiner Tunnel Test. In addition all foam plastics must be protected from the interior spaces of the building by a thermal barrier such as 1/2" gypsum board.
Because EPS insulation is an organic material it is flammable and should be kept away from sources of heat or flame, including, but not limited to open flames, welder's torches, sparks or other sources of heat. This thermal barrier requirement may be eliminated in roofing applications when the insulation has passed appropriate fire tests (UL 1256 or FM 4450) that are referenced in the codes or the roofing system has successfully passed large-scale fire tests appropriate for the application.
U.S. EPS resin suppliers have had EPS foam produced from their materials tested by Factory Mutual Research Corporation. All of these approved products along with a variety of roofing constructions are included in the current edition of the Factory Mutual Approval Guide. The approval by FM includes thermal barrier requirements, insulation density and thickness, coverboards, fastener and fastening patterns and membranes. These approved constructions must be used exactly as tested and without any deviations.