Using Engineered Geofoam for Garden Roofs

For most of the past century, the rooftops of commercial and institutional buildings have largely been places to locate unsightly mechanical systems. Architectural treatments, such as parapets and screens, provide visual relief from such equipment. Now, roofing professionals and building owners increasingly look at the roof as “found space”—a place to be planted and used, instead of hidden.

Facebook’s Frank Gehry-designed MPK 20 building sports a 9-acre green roof using EPS geofoam from Insulfoam.

Facebook’s Frank Gehry-designed MPK 20 building sports a 9-acre green roof using EPS geofoam from Insulfoam.

Throughout the U.S., garden roofs (or living roofs) are growing in popularity with more than 5.5 million square feet installed in 2014, according to Green Roofs for Healthy Cities. Most of that total was for private rather than public projects, indicating this is not just a government trend. In addition to providing attractive and usable open space, garden roofs offer environmental benefits, such as helping to slow and filter urban run-off.

Some of America’s largest companies have installed green roofs. Ford’s Dearborn, Mich., truck plant final assembly building sports one of the world’s largest living roofs at 454,000 square feet. In 2015, Facebook opened its MPK 20 office building in Menlo Park, Calif., with a 9-acre living roof featuring a 1/2-mile walking trail and more than 400 trees.

If you haven’t worked on a garden roof yet, it is likely only a matter of time until you do.

Addressing the Challenges of Garden Roofs

Weighing a fraction of soil, EPS geofoam fill creates ultra-lightweight landscaped features on Facebook’s garden roof.

Weighing a fraction of soil, EPS geofoam fill creates ultra-lightweight landscaped features on Facebook’s garden roof.


Adding plants and park-like amenities to a roof increases the complexity of the roofing assembly. Garden roofs present two primary challenges for roofing professionals to solve: minimizing the dead load and preventing moisture intrusion.

The project team for the Facebook MPK 20 building’s green roof met this two-fold need—and more—with expanded polystyrene (EPS) geofoam.

Weighing considerably less than soil, EPS geofoam is an ultra-lightweight engineered fill that can be used to create contoured landscape features, such as hills and valleys. The material weighs from 0.7 to 2.85 pounds per cubic foot, depending on the product type specified, compared to 110 to 120 pounds per cubic foot for soil.

Despite its low weight, EPS geofoam is designed for strength and has better load bearing capacity than most foundation soils. Geofoam’s compressive resistance ranges from approximately 2.2 psi to 18.6 psi (317 to 2,678 pounds per square foot) at a 1 percent deformation, depending on the product.

The garden roof on Facebook’s MPK 20 building provides ample open space and a half-mile walking trail for employees.

The garden roof on Facebook’s MPK 20 building provides ample open space and a 1/2-mile walking trail for employees.

EPS geofoam is also effective at addressing the second challenge of garden roofs: managing moisture absorption. The moisture performance of the various components in a green roof assembly is critical; retained water imposes additional loads on the roof and increases the risk of water damage to the roof assembly. EPS geofoam meeting ASTM D6817 standards works well here as it only absorbs 2 to 4 percent moisture by volume, even over long-term exposure, and it dries quickly. The moisture performance of EPS has been demonstrated in extensive in-situ applications and real-world testing, including research conducted by the U.S. Army Corps of Engineers’ Cold Regions Research and Engineering Laboratory. After burying EPS in wetted soil for nearly three years, the lab found that the material absorbed only 1.7 percent moisture by volume.

In addition to enabling lightweight, durable landscape features and helping to defend against water, EPS geofoam provides thermal insulation in garden roofs. Roofing professionals have used EPS insulation in roof assemblies for decades because it offers the highest R-value per dollar among rigid foam insulations.

Expect More Demand

Although green roofs currently account for a small portion of the billions of square feet of roofs in the U.S., expect to see more demand for them given their aesthetic and environmental benefits. High-performance materials, like EPS geofoam, can help provide a long-lasting, durable green roof assembly.

PHOTOS: Insulfoam

Insulfoam Introduces Branding for Full Line of EPS Insulation Products

To help design professionals, builders, homeowners and other customers more quickly find the insulation products they need, Insulfoam insulation offerings, including R-Tech insulations, are now categorized under the brand names InsulRoof, InsulWall and InsulGrade.

To help design professionals, builders, homeowners and other customers more quickly find the insulation products they need, Insulfoam insulation offerings, including R-Tech insulations, are now categorized under the brand names InsulRoof, InsulWall and InsulGrade.

Insulfoam, a manufacturer of block-molded expanded polystyrene (EPS), introduces branding for its full line of EPS insulation products. To help design professionals, builders, homeowners and other customers more quickly find the insulation products they need, Insulfoam insulation offerings, including R-Tech insulations, are now categorized under the brand names InsulRoof, InsulWall and InsulGrade.

“EPS is the only insulation you can use anywhere in the building envelope; at Insulfoam we offer specialized EPS products for use in roofs, walls, below grade and beyond,” says Ram Mayilvahanan, director of marketing for Insulfoam. “With such a huge product offering, this new branding helps our customers quickly find the right products to use among our numerous options. So, if you’re a roofer, you’ll look at the InsulRoof line to find your products, and don’t need to see InsulGrade below-grade options that aren’t applicable to current project needs.”

In conjunction with the new branding, Insulfoam has also revamped its website. The Insulfoam website now offers simple navigation to the major building categories: commercial and residential, with the InsulRoof, InsulWall and InsulGrade product groups clearly marked. The residential tab provides homeowners with home insulating tips for key areas, including energy saving tips for the house in basements and garage doors. Customers can also easily find on the new website Insulfoam’s other EPS offerings, including geofoam lightweight fill and EPS for cold storage buildings, flotation, packaging and architectural shapes.

Insulfoam EPS is 100 percent recyclable and offers a high R-Value per dollar. The features and benefits of InsulRoof, InsulWall and InsulGrade insulations are:

    InsulRoof

  • A wide range of faced, laminated and standard high-performance EPS insulation products for use on virtually any type of roof deck in new construction and reroofing applications.
  • Available in cost-saving applications including fanfold panel bundles, flute fill and tapered insulation.
  • Wide range of compressive strengths to help reduce insulation material costs.
  • Versatile to adapt to various roof shapes and roofing assemblies.
  • Products carry UL and FM labels.
    InsulWall

  • Full range of EPS insulation for use throughout walls, including cavity walls, on the interior faces of foundation walls, as exterior sheathing (including tongue-and-groove sheathing under stucco), gable ends, and as part of exterior insulation finishing systems (EIFS).
  • Insulfoam’s Total Wall System is one of the few insulated systems on the market that integrates weather resistant barrier (WRB).
  • Insulfoam EPS qualifies for several NFPA 285 compliant assemblies.
    InsulGrade

  • Full range of EPS products for use on foundation walls and under concrete floor slabs.
  • EPS outperforms extruded polystyrene (XPS) insulations in these applications due to EPS’s stable long-term R-value and moisture performance (it dries quickly and has minimal long-term moisture retention), and is lower cost.
  • Seven standard compressive strengths allow for more cost-effective specification without over-engineering the insulation under slabs.