Thermal resistance in exterior-insulated roof systems is provided by rigid board insulation. By installing insulation outboard of the roof framing, thermal bridging is reduced though the assembly. While several types of board insulation can be installed in this configuration, ROCKWOOL COMFORTBOARD™ stone wool is dimensionally stable, providing reliable thermal resistance over time. The insulation boards will not change shape when exposed to temperature changes or moisture, ensuring reliable long-term energy savings.

In this configuration, COMFORTBOARD™ increases the temperature of the sheathing and framing, reducing the potential for condensation and associated damage. If the insulation boards are wetted, they will not become a medium for mold or fungal growth. The insulation boards are water repellent and any moisture that manages to penetrate into the insulation will dry outwards, as the batts are highly vapor permeable. These properties improve the overall durability of the roof assembly