Building Insulation Products Geostructural Foam


Expanded Polystyrene (EPS) Geofoam has a long history of use in the building and construction industry. Going back as far as the 1960s, EPS Geofoam has been used as a geostructural material that has aided in the roadway, bridge, airport runway, and stadium seating building jobs - just to name a few.

EPS Geofoam is ideal for these types of projects, as it is highly versatile, durable, and lightweight. It is approximately 1% the weight of soil and less than 10% the weight of other lightweight fill alternatives, meaning it reduces loads imposed on adjacent and underlying soils and structures and costs less to ship and handle. It is the perfect tool to help solve engineering challenges, speed up construction schedules, and lower overall cost of construction.

Geofoam construction project
Geofoam construction project
Sketch of geofoam construction application
Geofoam use in stadium seating
Sketch of geofoam construction application


Traditional Below-Grade EPS Geofoam Applications

Details on Traditional below-grade EPS Geofoam's applications and use in construction in the following areas is contained in the download, “EPS Geofoam Applications & Technical Data.pdf”.

Above-Grade EPS Geofoam Applications

In addition to traditional below-grade applications, Geofoam also is now used in a few above-grade (in fact very above-grade) applications as well. One example is the use of EPS Geofoam as lightweight structural fill for roof-top swimming pools for hotels. In many of these cases, only limited modifications to existing building structure is possible so designers turn to Geofoam to provide the structural strength to support pool areas while adding only a small fraction of the weight as concrete options would. Another above grade application that is becoming more popular in recent years is using Geofoam to help construct green, roof-top decks, supporting grass or even gardens.

EPS Block Geofoam - Meeting Project Specifications

The American Standards and Testing Materials (ASTM) has two standards pertaining to EPS Geofoam. ASTM D6817 Standard Specification for Rigid Cellular Polystyrene Geofoam provides information on the physical properties and dimensions of expanded polystyrene intended for use as Geofoam. ASTM D7180 Standard Guide for Use of Expanded Polystyrene (EPS) Geofoam in Geotechnical Projects covers design considerations for the use of EPS in geotechnical applications.

Geofoam specifications (ASTM D6817) differ significantly from those for thermal insulation (ASTM C-578). Specifically, the geofoam compressive specification is for 1% strain while that for insulation is 10%. The reason for this is insulation is typically attached or laid on top of an existing structure and provides no significant structural support of its own. Instead, the wall or roof provides the structural support for the building and the insulation may be stressed beyond elastic limit (usually around 1% strain) with no detriment to the building. The opposite is usually true for Geofoam EPS. As a structural fill, Geofoam is designed to provide structural support in its wide variety of applications, from supporting loads on retaining walls to traffic on roadways. As such, designers typically ensure the exact type of Geofoam used has the compressive strength needed to support design loads and stay within its elastic stress-strain range of about one percent. In fact, in most Geofoam applications, the compressive resistance at a 1% strain will be the overriding consideration. Therefore, performance requirements for Geofoam applications must be evaluated individually as they relate to each project specification.

Cellofoam produces Geofoam from 100% virgin polystyrene bead. Insecticide options are available.

Please note Cellofoam North America Inc. is an expanded polystyrene foam manufacturer and not an engineering consulting firm. Thus, it is beyond our scope as a manufacturer of EPS Geofoam to provide design services on the specific use for our product. Users of our EPS Geofoam should consult with appropriate engineering experts to determine the exact type and specifications of EPS required for their project to meet structural and other design requirements, as well as jurisdictional building codes.


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