The three green roofs at our headquarters

Green and Cool Roofs

Green Roofs

Green roofs are roof surfaces covered in low-growing vegetation suited to extremes in temperature and moisture. Unlike traditional roofs, green roofs retain stormwater; reduce building heating and cooling costs; last longer than a traditional roof; and improve air and water quality – all within the existing footprint of the building.

Our headquarters’ green roofs use two soil depths: 4 and 6 inches. The 6-inch soil base captures more rainfall and allows greater root development of the plants it supports. Atop that soil are three types of vegetated surfaces:

  1. Traditional, which uses sedum planted directly into the soil base
  2. Trays made up of pre-grown sedum
  3. Pre-vegetated, sod-like rolls of sedum

The traditional green roof is the least expensive option, followed by the pre-vegetated options. Trays are the most costly option but are also easiest to install.

Cool Roofs

Unlike traditional black roof surfaces, our cool roof is a white rubber membrane that reflects the sun’s heat instead of absorbing it. Cool roofs can reduce roof surface temperatures by up to 100 degrees Fahrenheit, thereby reducing the heat transferred into the building below.