The foundation of energy-efficient building envelopes is a well-insulated concrete slab, which typically involves multiple material layers for insulation and drainage. Foamed glass aggregate is an insulating aggregate that consolidates structural performance, continuous insulation, and drainage into a single layer, replacing both rigid foam board and crushed stone beneath concrete slabs. With an R-value of 1.7 per inch, free-draining capabilities, and stable long-term performance, foamed glass aggregate simplifies subslab assemblies while meeting the needs of high performance building standards.
R1.7 per inch eliminates thermal bridging and improves energy efficiency.
Prevents moisture buildup beneath slabs while resisting rot, pests, mold, and mildew.
Combined insulation and drainage reduces installation complexity and costs.
Inert, closed-cell material contains no leaching chemicals.
Up to 125 psi once compacted, maintains slab stability and supports structural loads.
Ensures consistent performance while resisting moisture buildup, rot, pest, and mold.
A typical slab-on-grade assembly with foamed glass aggregate consists of the following layers from top to bottom:
This assembly eliminates the traditional layers of crushed stone for drainage and rigid foam boards for insulation, consolidating both functions into the foamed glass aggregate layer. The result is simpler construction, fewer materials to coordinate, and continuous thermal performance without interruption. For frost-protected shallow foundations, foamed glass aggregate can be used both beneath the slab and as insulated backfill around the perimeter, creating a continuous insulated envelope that protects against frost heaving while maintaining thermal performance.
Foamed glass aggregate has been sold in Europe for nearly 30 years and is quickly gaining popularity in North America.
Foamed glass aggregate is delivered on palletized 3 cubic yard bags in 53 foot flatbeds, 26 foot box trucks, or 130 cubic yard walking floor trailers (commercial projects only).
We recommend a minimum installed depth of 6” (R10) compacted to ensure even compaction and performance. Shallower depths may not compact evenly, which can affect load-bearing capacity and thermal performance.
Foamed glass aggregate particles range from 1” to 3” in size. These sizes occur naturally during the manufacturing process. We do not screen, grade, or size the material.
Yes. Glavel’s foamed glass aggregate supports passive radon systems. We recommend wrapping radon pipes with geotextile to maintain airflow. Active systems may slightly impact thermal performance and should be reviewed with your energy modeler if insulation levels are critical.
Foamed glass aggregate can be used beneath footings in many applications when properly evaluated. With compressive strength of 115-125 psi when compacted, it’s suitable for many residential and commercial loads. We recommend working with your engineer to verify suitability for your specific loading conditions.
Foamed glass aggregate installs like conventional aggregate with standard equipment. Use a lightweight vibratory plate compactor (<200 lbs) to achieve even compaction. 4-5 complete passes will achieve the necessary 25% compaction. A smooth-drum roller or tracked equipment with ground pressure of 4-7 psi may be used for larger areas. Avoid heavy tampers or compactors, which are too heavy for successful compaction.
