Cover boards are semi-rigid, relatively thin boards that are usually installed over the insulation layer to provide added impact protection, separation and support to the roofing membrane. They are available in a wide variety of materials, such as PIR-based, gypsum-based, cement-based, wood-based, etc.
Including a cover board in the roofing assembly enhances the performance of the whole roofing system and helps it last longer. Although not yet very common in Europe, cover boards are particularly useful when the roof has additional functions, performs in extreme weather conditions (such as hail or heavy snowfalls) or is exposed to frequent foot traffic (for example during installation or maintenance works). This can potentially damage the insulation layer, resulting in reduced thermal performance, which would in turn cause an increase in energy costs. From a life cycle cost perspective, it is therefore a smart move to protect the insulation layer.
Cover boards can be used in all types of roofs, both in new build and refurbishment projects. In renovations, they can be placed on top of the existing roofing system, providing a suitable substrate for the installation of the new membrane.
In combination with quality insulation, cover boards also provide other benefits: they increase moisture protection, improve acoustics and can even help achieve a better wind uplift performance and enhanced fire resistance.