Capital One Skypark

Project Overview

Capital One’s 11th story Skypark in Tyson’s Corner, Virginia required a green roof fill solution to support 4 acres of landscaping, an amphitheater, a biergarten, and a miniature golf course, all while meeting strict weight limits to minimize load on the headquarters below.

Design Challenges

Capital One’s Skypark included complex design elements that created challenges for the project team’s development, including the following:

Structural loading: 4 acres of planted areas with growing media depths reaching up to 4 feet in some locations, plus hardscapes, an amphitheater, biergarten, miniature golf course, and pedestrian traffic.
Fire safety requirements: Tysons, Virginia imposed strict fire requirements that ruled out traditional foam-based insulation commonly used in green roof assemblies.
Complex geometry: The design included varied topography, irregular shapes, mounds, and sloped areas that would be difficult to accommodate with rigid foam board.

Glavel as a Solution

Foamed glass aggregate was used as green roof fill and drainage throughout the entire green roof system. Rigid foam insulation could have been used but the flammability concerns were not permissible in local fire safety protocols. Foamed glass aggregate replaced rigid foam insulation and performed as drainage throughout the system while insulating the building from above.

Weight reduction: Weighing only 12 lbs per cubic foot (post-compaction), foamed glass aggregate minimized structural loads while supporting growing media depths for trees, shrubs, and native grasses.
Load-bearing capacity: Compressive strength up to 125 psi provided the needed stability underneath planting areas, pedestrian pathways, and pavers.
Flexible installation: The foamed glass aggregate’s form allowed crews to easily shape irregular geometries, create mounded topography, and steep slope surfaces by compacting the material in place.
Superior drainage and insulation: The free-draining structure facilitated water movement through the assembly while the R1.7 per inch provided thermal insulation for the performance specs while supporting the vegetated roof system above.

Project Name

Capital One Skypark

Location

Tyson’s Corner, Virginia

Application

Green Roof Fill

Market

Commercial Construction

Product

Glavel Foamed Glass Aggregate

Scope Completion Date

March 2022

Volume

2,200 cubic yards

Carbon Savings

Partners

HGA

Thornton Tomasetti

Columbia Green Technologies

Case Studies

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OnLogic’s 150,000 sq ft headquarters achieved 87% embodied carbon reduction by replacing traditional foam insulation with foamed glass aggregate in their subslab assembly.

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OnLogic’s 150,000 sq ft headquarters achieved 87% embodied carbon reduction by replacing traditional foam insulation with foamed glass aggregate in their subslab assembly.

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