JE Dunn recently completed the Rodman Innovation Pavilion at the world headquarters of global engineering firm Black & Veatch in Kansas City, Missouri. The LEED Certified innovation pavilion is 12,000 square feet and features a sleek, modern design that incorporates numerous eco-friendly features. The space utilizes geothermal and solar collection for heating, cooling, and power, and its large, sloping structure was designed as an organic extension of the surrounding Black & Veatch grounds.

A bluegrass green roof covers the breadth of the pavilion and is composed of a specialized growing medium of sand and peat. The growing medium was extensively developed to ensure maximum effectiveness for its specific environment and grass type. The green roof helps reduce the heat island effect of the facility, and absorbs rainwater that would otherwise become runoff and an additional burden to local infrastructure. Additionally, people working inside the office are treated with a verdant view in comparison to a traditional roof. Installation required extensive preparation, and was performed in three phases.

Phase I

The first step in building the green roof was holding a pre-planning meeting six months prior to the scheduled installation date. Collaboration between all project stakeholders from day one was key. The project team selected the desired bluegrass and growing medium components, then set to work acquiring materials for testing.

Prior to installing, the two main parts of the growing medium, sand and peat, had to be thoroughly tested for necessary specifications. While the sand was run through various sieves to measure particle size, the peat was tested for levels of moisture, organic matter content, and pH levels. Upon approval, these were mixed together, and then sampled again for testing.

Benefitting from thought-out planning decisions, the bluegrass was grown at a separate location, and tested much like the sand and peat. The sod grower had to submit grass clippings and cores to a testing agency to ensure the material grown matched the design specifications throughout this testing process. Once it was time for installation, the grass was cut, washed, and then shipped to Kansas City on refrigerated trailers.

Phase II

With preliminary testing completed, the team held a pre-installation meeting a month before the scheduled installation date to review the testing process, schedule and site logistics of the installation procedure. Additionally, the sand and peat materials needed testing within 60 days of the installation date to ensure the tested materials were the actual materials that would be installed on the roof. The sand and peat characteristics change over time, so it was important to perform this test as late as the schedule allowed. Prior to the actual application of the grass and growing medium, the roof membrane was evaluated to ensure its ability to hold the weight of the green roof. The team arranged 40 tanks of water around the roof to simulate the load.

The actual installation process began with laying down the growing medium on top of the roof insulation and root barriers, followed by fertilizer, and finally the roots of the bluegrass sod. Maintaining a daily work log of green roof maintenance activities was crucial to keeping track of progress and monitoring factors like daily soil and ambient temperatures, chemical application logs, and irrigation applications.

Phase III

Although installation was complete, further testing was required to determine whether or not the grass was adapting to its new environment. Clippings were measured for various nutrient levels, like nitrogen, potassium, magnesium, boron, zinc, and many more. The team used the results of these tests to make small adjustments, and then sent new samples to evaluate their changes. This testing process occurred throughout a few months until the roof was certified. Maintenance and care of the roof is being passed over to the project owner.