Making Progress with Green Roof Maintenance?
In the last decade in North America, we've seen many Green Roofs where the intended plants never really flourished. We estimate that in the US at least 50% of the green roofs are not performing to their fullest potential. This can be observed by simply looking at the most obvious of indicators, the plants themselves, regardless if they were planted on purpose or somehow found the space to take root.
The most performance/maintenance deficits on extensive Green Roofs we discovered on thin-layered systems (below 3 inch), pre-planted boxes (often called modular systems or hybrid systems), Green Roof Systems from roofing manufacturers with ineffective components, single source warranty-systems, or design intents without consideration for the needs of plants.
As advertised and the final product (sloppy work all around)
Because of their immense marketing efforts, these systems are not only much more costly (whether thin or thick), they were also hardly designed or engineered with maintenance in mind – or simply not designed with common sense. For these manufacturers revenue seems all what matters and references that look good on the first day for some pictures to post on Social Networks.
Often Planners and Engineers want to have the least work with the “unknown” territory Green Roof and hire an intern to google all the information they are looking for or much more likely, the nice colorful advertising with long-term warranties baits them. Sometimes people fall in love with systems that seems innovative, new or that promise the most LEED points. It is all so convenient but nothing really helps the plants to grow.
As advertised and the final product
At the time when it does not work anymore, everybody pushes the “Old Maid” to others since the decisions were made democratically among all participants and because the building owner trusted the experts he ends up with the “Old Maid” and an additional bill that can go into the millions.
There are many reasons for building owners to question things in the process and to ask for a third party advice e.g. experienced Green Roof experts. The costs for advice are typically only a percentage of potential savings before construction and likely save expensive repair, renovation or rebuild in the first 5- 6 years.
Our advice: Don't play cards - ask for advice.