Foam glass gravel is a lightweight aggregate that combines compressive strength, insulation, sustainability, and cost savings.
It delivers high compressive strength for load-bearing applications, such as subslab insulation, bridge abutments, roadways, and culverts, while offering lightweight performance and drainage for ground improvements, and industry-leading decarbonization to meet sustainability goals.
Whether you’re building high-performance commercial projects, specifying materials for long-term durability, or driving toward carbon-reduction targets, Glavel is the low-carbon solution for subslab insulation and structural fill.
Commercial Construction Technical Guide
Project Overview
The Vermont-based tech company OnLogic recently completed construction on their new 140,000 square foot headquarters in South Burlington, Vermont. This new campus accommodates 150 employees and a full manufacturing facility to produce industry leading industrial computers. This project was done in conjunction with ReArch, Wiemann Lamphere, and SD Ireland.
Design Challenges
The OnLogic team prioritized the use of sustainable, locally sourced materials for their new headquarters. They sought to create an energy-efficient space with stable temperatures for industrial manufacturing processes. To minimize heating and cooling costs, the building required a high performance envelope that met both thermal performance and environmental goals.
Glavel as a Solution
Glavel played a role in achieving the project’s sustainability and performance goals. Its lightweight and insulating properties eliminated the need for foam insulation, ensuring long-term energy efficiency while providing the conditioned space necessary for employee comfort and consistent manufacturing processes. The use of Glavel resulted in an 87% reduction in embodied carbon emissions compared to a traditional insulation detail.
Material transparency is a responsibility. We are reshaping how the built environment addresses insulation, structural fill, circularity, and decarbonization, while holding ourselves to high standards of disclosure.
That’s why we have both a Declare Label and a third-party verified Environmental Product Declaration to verify what goes into our material and how it sets the bar for low embodied carbon materials.
Some of the Organizations Building With Us
Product Basics
Foam glass gravel is a lightweight, insulating aggregate made from 100% post-consumer recycled glass. It serves as a cost-competitive, low carbon replacement for rigid foam board, geofoam, and other lightweight fill materials in a variety of construction applications.
Foam glass gravel has been produced in Europe for decades. Glavel has been manufacturing in Vermont since 2022, bringing proven performance to North American commercial and civil projects.
Foam glass gravel is also be referred to as foamed glass aggregate, FGA, or cellular glass insulation.
Recycled glass aggregate is milled into a superfine powder and combined with glycerine and sodium silicate before being heated in a kiln to 1,500°F. The glass softens at that temperature and sinters into a foam glass slab while the glycerine off-gases and creates a network of closed cell micropores. The foam glass slab exits the kiln and fractures into foam glass gravel due to thermal stress from temperature change.
Performance Properties
Glavel has an R-value of 1.7 per inch. Because it’s a closed-cell material, it does not absorb water, so the R-value remains stable in damp conditions. Unlike foam board, its thermal performance doesn’t degrade over time due to moisture exposure.
Glavel weighs 10lbs per cubic foot.
Glavel’s compressive strength is 110–125 psi at 25% compaction, making it suitable for heavy commercial slabs, deep fills, and certain load-bearing applications. Always consult a structural engineer for footings or heavily loaded assemblies.
Ordering Overview
Glavel is only available directly through the manufacturer. If you are a distributor interested in a distribution agreement, please reach out!
You can place an order by calling or emailing our sales team. We’ll walk you through quantity estimates, shipping options, and delivery timing.
We regularly ship Glavel across the Northeast and Mid-Atlantic. We’ve also served projects in the Midwest and beyond. Shipping feasibility depends on volume, freight availability, and lead time.
Installation Intel
Glavel is used in a variety of applications, including sub-slab insulation, structural fill, and green roofs. Each application has its own specific installation needs. Our sales team is happy to talk through designs and how Glavel can be integrated into your project.
Glavel should be compacted 25% at a maximum lift height of 15″ (which would compact down to 12″). Overcompacting is unnecessary and will not increase R-value or load bearing capacity.
Use a lightweight vibratory plate compactor (<200lbs) to achieve even compaction. 4-5 complete passes will achieve the necessary 25% compaction. A smooth-drum roller may be used for larger areas. Avoid heavy tampers or compactors, which are too heavy to successfully compact Glavel.
Yes, Glavel 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.
It depends. Some engineers will allow footings to bear directly on Glavel, but it must be evaluated case-by-case. Always consult your structural engineer for load-bearing applications.
In certain cases, yes. You can insulate the exterior of stem walls by using Glavel as loose or compacted fill, as long as it is capped and not left exposed.