• Sub-slab insulation is primarily for comfort and health, unless in-floor heating is installed
• Thermally separating the slab from ground temperatures, maintains a warmer slab
  • A warmer slab in the summer reduces condensation caused by relative humidity
• Condensation on basement slabs can lead to mould growth on floor coverings (carpets, rugs, etc.), or on stored materials and wall finishes close to the floor
• In-floor heating requires the use of sub-slab insulation to minimize heat loss to the ground
  • Rigid foam board has a proven record and is recommended in hydronic design manuals

There is no industry accepted standard for radiant insulation products. Ensure that the sub-slab polyethylene is next to the concrete and foam board insulation is below the polyethylene. If the foam board is on top then water can pool on the polyethylene and damage/reduce the insulating effect of the foam