Sarnatherm Lightguard (LG) and Heavyguard (HG) are extruded polystyrene insulation boards with a modified concrete top surface.  Sarnatherm LG & HG are used in protected membrane roof systems (PMRS) or “upside down” roof systems where the roof membrane is installed underneath the insulation instead of on top.

Sarnatherm LG & HG  are both 2 feet by 4 feet (0.6 meters by 1.2 meters) with either 2 or 3 inches (50.8 or 76.2 mm) of extruded polystyrene insulation.  They have interlocking tongue and groove joints that offer maximum protection for the roof membrane while providing wind uplift securement. 

The product comes in two thicknesses for the concrete top surface - Lightguard is 3/8 inch (9.5 mm) and Heavyguard is 1 inch (25.4 mm).  Both LG & HG can be ordered with or without a white reflective coating for energy efficiency.

Features and Benefits

  1. Sarnatherm LG and HG consist of modified concrete bonded to durable,
    moisture resistant STYROFOAM® extruded polystyrene insulation
  2. Removal and re-installation of the ballast and insulation is easy, and it can be reused
  3. The membrane is maintained at a nearly constant temperature, reducing the freeze-thaw cycling and membrane temperature
  4. In a Protected Membrane Roof System, the insulation, separation layer
    and ballast are loose-laid, and these components can be reused after
    maintenance or re-roof construction
  5. White reflective coating reduces rooftop temperatures
  6. Reduces energy costs — retains at least 80% of its R-value over 15 years
  7. Reduces yearly membrane maintenance costs
  8. Can be laid over existing membrane to add insulation
  9. Typically results in the dew point being above the membrane