Glavel® Foamed Glass Aggregate

Glavel is a coarse, crushed lightweight aggregate made from 100% post-consumer recycled glass, foamed under heat into a stable, closed-cell structure. Unlike a fine granulate, Glavel is sized like crushed stone — which makes it a direct, high-performance substitute for the rigid foam board and crushed stone layers used beneath slabs, around foundations, and in other bulk fill applications.

A single material does the job of three conventional layers at once: insulation, drainage, and capillary break — with no petrochemical foam and no off-gassing.

Glavel is used in:

• Sub-Slab Insulation: Installed and compacted beneath a concrete slab, Glavel provides continuous thermal insulation while eliminating thermal bridging — the assembly required for Passive House and other high-performance envelope certifications. It has been used at scale on Passive House residential projects and commercial facilities achieving R15–R20+ sub-slab performance.
• Foundation Wall Backfill: As loose or compacted backfill outside foundation walls, Glavel insulates the foundation from the exterior while remaining free-draining — provided it stays capped and is not left exposed.
• Frost-Protected Shallow Foundations: Used both beneath the slab and as insulated perimeter backfill, Glavel creates a continuous insulated envelope that protects against frost heave while maintaining thermal performance — reducing the need for a full frost-depth foundation.
• Geotechnical & Infrastructure Fill: Its light weight and high shear strength make it a proven material for retaining wall backfill, embankment fill, bridge approach fill, and slope stabilization — approved by transportation departments across North America for exactly these uses.
• Green Roofs: As a lightweight drainage and insulating layer, Glavel significantly reduces the structural load a green roof imposes on a building, compared with conventional soil or stone drainage media.
• Radon Mitigation Compatibility: Because it's a free-draining granular layer, Glavel supports passive radon venting the same way a standard gravel bed does — radon piping run through the layer just needs to be wrapped in geotextile to preserve airflow.