Gates Foundation | Seattle, WA


Large tree grates on structure

This unique installation began in the offices of Gustafson, Guthrie and Nichol, with their vision of planting trees in the entry courtyard to the Gates Foundation parking facility, and covering the tree pits with Urban Accessories Viper style grate.

This ambitious idea had one primary challenge: Provide an adequate soil base to support healthy tree growth, while planting the trees directly into an underground parking structure. The solution was to construct large concrete tree planters in the roof of the underground parking garage, and integrating the planters into the existing structural elements of the garage itself, by making each one custom sized.

The hard part out of the way, GGN came to us for ideas on how to grate seven tree pits of roughly 6' x 18', each one slightly different than the next.

How do you plant trees on the roof of an underground parking garage?

Enter Urban Accessories and the remarkable team we worked with from Sellen Construction.

In order to provide the large coverings, we designed a new 36" x 36" panel grate which would be arrayed in a 2 x 6 grid to cover the rough 6' x 18' dimension. The grate would then be modified to allow for a tree in the center of the array, and each end piece would be custom molded with additional border width to allow for the overall dimensional flexibility required.