Principal of Architek [www.architek.com ] in Vancouver, Ron Schwenger has a living architecture technologies company, and sage advice on vegetated roofs, living walls, living facades, rainwater harvesting, storm water mitigation.
SABMAG Architek supplies and installs vegetated roofs and facades. Are we past the “early adopter” stage with these systems, and are they becoming more mainstream?
RS Although green roofs and living walls are being used more frequently in the past five years or so in North America, we still have a long way to go to catch up to Europe where they have used these technologies for five decades. There is still a considerable amount of education needed in the area of specifications and standards to help with long-term performance of green roofs and living walls. Also, we need municipal bylaws to catch up to sustainable building technologies, and incentives to encourage green building practices.
SABMAG What does an architect, project manager or building owner need to think about when they are considering using these systems?
RS Protecting the building envelope and providing genuine sustainable benefits depend a lot on the integrity of the engineering behind the green roof system chosen. Building owners and architects also need to decide if the green roof area is going to be accessible or not. Plant selection is key in these decisions. Although green roofs only need minimal maintenance, they do need to be cared for just like any other living natural landscape, and will favourably impact the sustainable performance of the building more so than any other system. In extensive green roof situations, the saturated weight is usually under 22 lbs. per square foot and additional structural support is probably not needed, however, in any semi-intensive or intensive green roof installation using more than 6 inches of soil/grow media, a structural engineer’s involvement is mandatory.
Living walls can be very impressive and spectacular, however, much like a shiny new sports car, there is a serious commitment required towards ongoing maintenance. Once again, orientation, plant selection, and water management are key.
SABMAG Just adding to the above, what is your sense of return on investment of capital costs [design, materials and installation], and maintenance?
RS Although green roof vegetation layers are an extra cost [usually about $15- $17 per square foot], there is a long term savings in the form of protecting the waterproofing membrane and usually extending the lifespan by 2 to 4 times. There is significant cost savings to municipal infrastructure as well. The storm water mitigation qualities of green roofs hold back water that would normally be immediately deflected in to the storm sewer system, preventing flash flooding and costly damage.
Both green roofs and living walls or facades play a key role in a biophillic approach to building design and subsequently cool and improve air quality which leads to healthier and more productive living, learning, healing and working environments.
SABMAG You’ve worked on some complex projects, such as the Van Dusen Botanical Garden pavilion in Vancouver, but are there some types of projects where vegetated roofs and facades don’t make sense?
RS In any given circumstance one has to measure the benefit versus the cost and risk. Although, Architek is very fortunate with our relationship with our partners like Zinco and Greenscreen, we can handle almost any architectural green roof and wall. I continue to be amazed at what I see happening here and in other parts of the world and keep an open mind to any possibilities. The Central Building in Sydney, Australia, for example, has living walls and Jakob cable facades literally covering the entire outside faces of two towers with manoeuvrable mirrors above directing sunlight into the towers’ canyons to insure the plants thrive. Proof, that when we think it through, we can design and build almost anything.
SABMAG What kind of support or interaction does a supplier/installer need from the architect and project manager for the installation to finish on time and on budget?
RS Excellent question. The construction industry is dependent on a competitive bid and tender process for cost controls which makes it conflicting for experts in specific systems to get involved at the design stage. But I believe that we are not just a supplier of living building systems, we are also the source for expertise, detailing and cost efficiency. Therefore, the earlier we get involved in the design stage, the more thought out and complete the design detailing will be. Flattening the process and involving industry experts early in the process will lead to a better system in the long run and almost always save costs. We provide shop drawings, and can offer design-build services.
↦ SUBSCRIBE TO THE DIGITAL OR PRINT ISSUE OF SABMAGAZINE FOR THE FULL VERSION OF THIS ARTICLE.