Rmax Thermasheath®-3 is an energy-efficient thermal insulation board composed of a closed-cell polyisocyanurate (polyiso) foam core bonded to reinforced aluminum foil facers with clear coating for limited protection against oxidation on each side.

Thermasheath®-3 is suitable for use in cavity walls, masonry walls, vaulted ceilings and some limited roofing applications, as well as many other building envelope continuous insulation applications. It is also an integral piece to maintaining the continuous insulation solution when Thermasheath®-SI is used as intermittent bracing.