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Is Your Green Roof a Pest Paradise?

By Jennifer Brumfield, Training and Technical Specialist, Western Pest Services

Green roofs are steadily sprouting across the country, with the North American green roof industry experiencing 10.3% growth between 2015 and 2016. This form of living architecture helps buildings reduce their water runoff, increase their insulation and even attract more renters.

Green roofs aren’t just appealing to building management and renters, however. This treat for residents could also become a paradise for pests due to the abundance of food, water, and shelter. This could ultimately result in damage to your property – and your bottom line.

By understanding the potential pest threats and implementing proper prevention techniques, your green roof can remain an oasis for people, not pests. Just remember to stay “GREEN”!

G: Get to Know the Pest Threats – Pests don’t have to fly to enjoy a spot on your rooftop. From rodents to ants, meet the pest threats that you could be up against.

R: Redesign your Roof – Many of these pest threats can be deterred by properly designing – or redesigning – your green roof. When thinking through the layout of your roof, plan to position vegetation away from roof entrances or exits. In addition, avoid placing plants by the ledge of your building, as pests can easily move from vegetation to open windows.

Ponds and/or fountains are a common feature for green roofs. While beautiful, be warned –standing water can also be a breeding ground for pests, including mosquitoes.  Ensure that all water is constantly circulated, to help deter mosquitoes from laying their eggs on the surface.

E: Evaluate Vegetation – Oftentimes, preventing pest threats can be as simple as choosing the right vegetation. Plants that produce nuts, seeds, or fruits are particularly appealing to flying pests who are looking for a quick meal. Instead, opt for one of these varieties:

In addition to vegetation, it’s important to evaluate mulch options. Cedar mulch is recommended over organic mulch because it’s considered a natural insect repellant and can help prevent the spread of ants.

E: Exclusionary Practices – Exclusion is an essential element of any integrated pest management (IPM) strategy. IPM aims to prevent pest activity before it occurs through assessment, implementation of prevention tactics, and ongoing monitoring of pests.

Exclusion is a proactive technique that entails sealing all possible pest entrances, essentially “excluding” any pests from moving into your facility.

While it is impossible to fully seal off a green roof, eliminating any cracks, holes and other voids around the exterior of your building is essential. This includes gaps around doors, pipes and fixtures, which can be convenient entranceways for insects or rodents – rats can fit through holes as small as a quarter and cockroaches can squeeze into cracks measuring just one-sixteenth of an inch. Use water-resistant sealant, copper mesh and caulking to close gaps around utility connections and outlets.

N: Next Steps – IPM is not a one-time job. It’s an ongoing cycle that requires the involvement of all building stakeholders. Moving forward, be sure your green roof incorporates the following preventative measures:

As green roofs continue to grow in popularity, it’s essential to remain vigilant about potential pest threats. By staying G.R.E.E.N, your building can reap the benefits of your living roof – and say so long to pests.

Jennifer Brumfield is a Training and Technical Specialist and Board Certified Entomologist for Western Pest Services, a New Jersey-based pest management company serving businesses and homeowners in major Northeastern markets.

Originally featured at Multifamily Executive.