Vegetative roofs are a great way to combine sustainability with amenities, as they can be inviting places for building occupants. However, improper planning for the maintenance demands means you might be dealing with more than you bargained for in terms of costs and labor.
Prepare for the responsibilities of a green roof with these three tips:
1) Enlist Multiple Experts
One of the biggest mistakes facility managers make when implementing or considering vegetative roofs is the need to consult with only one expert. A roofing expert will help you identify the structural demands of a vegetative roof, but they can’t attest to regional and climate-based concerns about plant life and the maintenance it requires.
Therefore, you’ll need two types of experts – one for roofing and another for vegetation and maintenance who is knowledgeable about the best kinds of plants for your climate. This person will identify plants that can survive and thrive in your environment, as well as ones that require less upkeep.
Of course, depending on what kind of vegetative roof you’re looking into, you will need to include plant life that’s compatible with the structure of the roof. Make sure your roofing and vegetation consultants have an open dialogue to ensure that the roof can work optimally for as long as possible.
2) Know Your Roof
If your roof requires a lot of maintenance work after a severe weather event or from wear and tear over time, knowing the details of your roof’s installation and materials will help you save money, time and labor.
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Familiarize yourself with your roof’s warranties. Compare your detailed record of the roof’s installation with your warranty policies when you need to make major repairs.
“In general, warranties insure the owner against defective products and/or inadequate installation by the contractor,” notes the Whole Building Design Guide (WBDG). “They can cover all products of the vegetative roof installation including the waterproof membrane, root barriers, filter fabrics, growth medium, drainage layers, etc. as well as the workmanship of the installation subcontractors. There are several waterproofing manufacturers that will warrant the entire vegetative roof system, including removal and restoration of the overburden, if they provide all of the materials in the original construction.”
To stay ahead of major maintenance needs, WBDG identifies four things to consider when it comes to your vegetative roof:
- How durable are the components of your roof? Identify when they will need replacement or checkups.
- Did one contractor install all the features of the vegetative roofing system (e.g. waterproofing membrane, growth medium, etc.), and are they from one manufacturer? If you obtain all components from one manufacturer, all of the parts of the green roof will be covered under one warranty and there won’t be liability disputes if there is an issue.
- If a number of manufacturers and/or contractors are involved, clearly define the extent of each warranty and what they individually cover. For example, does the membrane warranty also include reasonable uncovering and restoring the vegetative assembly in order to perform the warranty work?
- Does the warranty cover the plants? Many vegetative roof warranties don’t cover plant survival, but some include it as long as the owner purchases a maintenance package.
3) Establish a Transitional Period for Maintenance
Unlike other building systems and roof types, a vegetative roof is a living, breathing ecosystem. This means many things can go wrong and cause issues for your building.
To counter this, WBDG suggests including a minimum two-year maintenance and warranty period in any initial construction contract. This ensures plant establishment, maintenance personnel training and comprehensively addressing local pest issues.
If you can implement this two-year period for your vegetative roof, you will be able to avoid a number of serious issues that require expensive solutions.
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After that period has expired, vegetative roofs should receive maintenance from trained personnel at least twice a year, notes WBDG. If untrained people perform maintenance, manufacturers are likely to void any warranties.
Justin Feit was an associate editor for BUILDINGS.