Green Roofs Keep Getting Better

There are a lot of good reasons for installing green roofs – or more specifically vegetated green roofs. High up on the list is stormwater management. A green roof will absorb rainwater as it falls, storing some in the soil or in the plants themselves, then slowly releases the balance. This is an excellent stormwater management strategy that reduces quantity and improves the quality of stormwater runoff. Next on the list is the reduction of impervious surfaces on site, which is closely related to managing stormwater. Spiezle is using this approach with a community college client to help keep a new building addition below site limits for impervious coverage. A third benefit to vegetated roof systems is their ability to protect and extend the life of the waterproof membrane from degradation which in turns keeps the building dry and secure.

Vegetated green roofs are low maintenance when properly installed and maintained, and have a positive impact on building heating and cooling. Intensively planted vegetated roofs can increase habitat diversity and provide pleasing views for building occupants. A number of our educational clients integrate vegetated roofs into their curriculum, thus making them valuable assets to learning environments. But 2 new studies are taking the benefits of green roofs even further.

Both studies out of Australia looked at the impact of green roofs on work performance; something of interest to both our corporate and educational clients. Here is how they did it: they devised a test to gage a participant’s ability to maintain a sustained level of attention on a task. The researchers recorded the participant’s erosion of attention over time. They then introduced a 40 second break where participants either looked at a typical roof or at a simulation of an intensively planted vegetated roof. What they found was that those participants who viewed the vegetated roof scape had a pattern of response that suggested higher sustained attention. The implication here is that views of greenery can help sustain your attention to the task at hand and improve performance and productivity.

A related study looked at indicators of tension and enthusiasm related to a baseline task and changes to those indicators when participants took micro-breaks to view either a concrete roof or a vegetated roof. The results were similar; views of a vegetated roof reduced reported tension and increased reported enthusiasm related to the baseline task, although there were differences reported by women and men (go figure).

So what can we take away from this? Neither of these studies is exhaustive, but they are consistent with what clients anecdotally report and what social science is finding; that our human connection to nature is strong and has an impact on our functioning and well-being. If that can translate to better learning outcomes or more productive employees then vegetated green roofs have compelling advantages. We have helped a number of our clients take advantage of the benefits of vegetated green roofs. They might be an elegant and appropriate solution to your next project too.