Welcome to our lab!

This is the Green Roof Diagnostics laboratory and learning center. This world-class facility allows us to study the intricacies of green roof components and green roof profiles at a scale never seen before in our industry.

The lab includes controlled and uncontrolled areas. The controlled "Rain Lab" is used for simulating a wide range of storm events at slopes ranging from dead flat to 2.5 percent. The uncontrolled areas include outdoor platforms and a weather station, used for monitoring runoff, evapotranspiration, and a range of weather phenomena. Read more below.

green roof testing laboratory rainfall simulator
Rain Lab and control room.
80 square foot (7.4 square meter) green roof cassette in the rain lab (view from side)
80 square foot (7.4 square meter) green roof cassette in the rain lab.
80 square foot (7.4 square meter) green roof cassette in the rain lab (longitudinal view)
80 square foot (7.4 square meter) green roof cassette in the rain lab.
overhead view of moveable green roof testing cassettes
Between tests in the rain simulator, green roof cassettes grow outdoors. Each cassette is fully vegetated.
green roof media / green roof soil over mineral wool
We are able to test any combination of components. Showing mineral wool assembly.
green roof drainage layer installation
We are able to test any combination of components. Showing cup-type drainage layer installation.
overhead view of stationary green roof testing platforms
Outdoor, uncontrolled green roof platforms complement research in the rain lab.
view of stationary green roof testing platforms with rain laboratory in background
Green roof platforms allow monitoring of stormwater performance and runoff water quality.
weather station on roof of green roof testing laboratory
Our weather station allows correlation between green roof observations and weather phenomena.
overhead view of green roof cassette to monitor plant health
We track the vegetative health of each green roof platform and cassette throughout the year.
green roof platform testing compression
We compact each green roof assembly to ensure tests most closely replicate actual field conditions.
worker standing on green roof testing platform assembly
Cold, winter days are a great time to change out platforms to test new profiles!

A few ways we believe our lab is special:

High precision. The Rain Lab is equipped with sensors to allow a full water balance of each run, i.e., we can measure any overspray or drips that land on the floor, so we know exactly how much was sprayed on the green roof. We test for high-intensity rainstorms, which inevitably produces overspray. Further, all green roof profiles are weighed continuously throughout the tests, which is far more precise than the more common (and less expensive) method of using soil moisture probes

High volume. The Rain Lab, in particular, is equipped to produce a very high volume of tests. This is because each green roof cassette is placed in the lab for only a few hours during a simulated storm, allowing for multiple tests to be run per day. This rate of testing enables us to isolate variables and produce from one facility within a few years more accurate performance parameters than could be done in dozens of outdoor test sites over the course of decades. This speed is necessary for rapid improvement within the green roof industry

Large sample size. Green roofs are more complex than many other green infrastructure best management practices (BMPs) such as rain gardens. Much of this complexity is due to the thin nature of the green roof, and the interaction of multiple layers and edges. We do some universal small-scale testing (such as 150 mm (6 inches) diameter, or 300 mm square (1 square foot), but most of our testing is focused on a mid-range of 36 square feet (3.3 square meters) to 80 square feet (7.4 square meters) to lessen edge effects, and to provide intermediate data between micro-scale and full-sized rooftop installations

Quality and quantity. We believe a green roof is more than just a hydrologic tool, more than just a horticultural curiosity... more than the sum of its parts! This is why our studies include hydrology, soil biology, vegetative health, water quality, nutrient cycles, and more. We believe problem-solving is not complete until the solution is balanced, so we try to measure and evaluate all relevant criteria

Vegetated. Believe it or not, a lot of green roof hydrologic research does not include plants. We have observed plants having a measurable impact on hydrologic performance, and whenever possible, any tests we perform on green roof assemblies include vegetation

Modular and scalable. We can do a lot with one laboratory in one climate zone, but we are always looking for collaborators in other climate zones. Our lab, and accompanying custom monitoring and data analysis software is scalable. Contact us if you are interested in collaboration