Below‑grade assemblies use one of the most thermally conductive building materials, concrete. Codes are changing and we need to insulate these assemblies from the exterior of the building envelope for both indoor comfort and durability. Below-grade assemblies also demand materials that can withstand constant moisture, soil pressure, and thermal fluctuation. PowerWool RigiBoard® is engineered specifically for these conditions: its composition resists degradation and pest damage, maintains dimensional stability, and provides consistent insulation even under slab or against foundation walls. By choosing RigiBoard®, architects and builders ensure assemblies that remain resilient, safe, and efficient for decades. Using PowerWool is a stone simple solution for below grade applications.
Installed beneath slabs, PowerWool RigiBoard® creates a continuous thermal layer that reduces heat loss to the ground while supporting vapor permeability for balanced moisture control. On foundation walls, boards are mechanically fastened or adhered to create a durable exterior insulation system that integrates seamlessly with waterproofing membranes. The rigid format simplifies sequencing, allowing crews to maintain alignment and continuity across transitions. Its compatibility with standard detailing makes RigiBoard® straightforward to specify and efficient to install. (show image of layers for assembly, from bottom to top, gravel, RigiBoard, Poly, Concrete) (show image of layers for wall, Concrete block, waterproofing membrane, RigiBoard, dimple mat (recommended), soil)
PowerWool RigiBoard® offers a rock solid approach to below grade solutions with a product that is not susceptible to pests, offers added drainage and will not trap moisture. It avoids issues like shrinkage or thermal drift, delivering stable R‑values over the life of the building. Its mineral composition contributes to fire resistance and acoustic dampening, while its recyclability supports green building certifications. For architects, this means assemblies that meet stringent performance criteria; for builders, it means fewer callbacks and a product that installs cleanly without specialized equipment. In short, RigiBoard® delivers durability, safety, and environmental responsibility that elevate below‑grade construction for decades to come.
