When evaluating green roof insurance consider the benefits – and potential risks – that come with a green roof for your residential or commercial building.
This article describes the many benefits of green roofs and also how insurance for green roofs works and what you need to know before signing off on a contract with a green roof installer in NYC.
What Is A Green Roof?
A green roof is a category of roof involving a partial or complete covering of the roof surface with live vegetation, and may simultaneously incorporate “green” technologies, such as solar panels.
Green roofs have many benefits, including, but not limited to, potential extended roof lifespan, sound attenuation, heat island reduction, reduced stormwater runoff, and improved water and air quality.
Heat Island Effect
As anyone who has worn a black t-shirt on a sunny day knows, black surfaces can become up to 70°F (40°C) hotter than lighter, or white surfaces. In cities, the heat island effect is caused by the absorption and radiation of heat by dark, non-reflective pavement and building surfaces.
This is the reason why many urban areas typically have higher temperatures many months of the year than rural areas. In fact, traditional roof surfaces (i.e. those with rubber membrane, EPDM, asphalt tile or shingles) can absorb up to 83% of the sun’s heat and UV rays causing significant heat buildup.
This incremental heat is transferred to the inside of the building increasing energy loads and conditioning costs… HVAC systems must work harder to maintain indoor environmental quality.
In contrast, a vegetated roof reduces the heat island effect because plants naturally absorb sunlight for photosynthesis. This prevents surrounding surfaces from absorbing and radiating the temperatures. Therefore, a green roof can reduce energy loads and costs when installed on a building’s rooftop.
And, as described below, a green roof can help reduce the cost of a solar PV system by boosting its effectiveness.
Stormwater Protection and Native Vegetation
Vegetative roofs can improve stormwater quality by absorbing and filtering rainwater. This reduces stormwater runoff and prevents waste from collecting and transporting pollutants and suspended solids to surface waters.
A green roof may have additional environmental benefits if it contains natural or adapted vegetation.
According to the United States Green Building Council (USGBC), adaptive or native plants are “plants indigenous to a locality or cultivars of native plants that are adapted to the local climate and are not considered invasive species or noxious weeds”…
Such plants promote biodiversity and provide habitat, while also reducing the amount of water and fertilizer required for healthy growth.
Green Roofs Improve Solar Panel Performance
Data suggests that “bio solar green roofs”, those that are both vegetated and incorporate solar PV, improve solar panel productivity.
One study showed an average of 6% increase in yield from solar photovoltaic (PV) panels that were installed on green roofs rather than bitumen roofs. The increase in energy output from these PV panels ranged from 1-10%.
Similarly, Engineering for Change reported that the Bronx Design and Construction Academy in New York City found that green, or living, roofs boost solar panel energy production by 3%.
The studies suggest that the vegetation on the roof lowers the ambient temperature, which improves the solar panels’ output.
This means that installing solar panels on a green roof will result in a shorter payback period and higher ROI than installing them on a black, bitumen roof.
Downsides of Green Roofs
While green roofs have many environmental benefits, they do have a few disadvantages.
A vegetative roof is not a do it yourself project… Installing an intensive or extensive green roof requires working with a professional green roof vendor (and/or installer) with specific experience and knowledge of green roofs, not just conventional roofs.
Green roofs are also more expensive to install than conventional roofs and could have higher maintenance costs.
As described below, there are second and third order effects of installing a green roof that include maintenance and insurance costs.
By comparison, a traditional or simple “reflective roof” or “cool roof” (high albedo paints or coatings that reflect rather than absorb the suns rays) usually pay for themselves in a couple of years.
When considering both materials and labor, a green roofs can cost $15-$35 per square foot, or more, whereas a “cool roof” costs between $0.75-$3 per square foot. The lower $/psf is for high albedo coatings or paints, and the higher range is for PVC single-ply membranes.
Because of the higher costs and maintenance associated with a green roof, the payback for a green roof may be much longer than the payback for a cool roof.1
Green Roof Insurance
Normally a roof would not need insurance considerations on its own… However, a green roof is a significant investment and should be adequately covered by your property insurance.
And because a green roof may increase activity on your roof and/or be incorporated with solar panels or other technology, reviewing the insurance for your building is a necessary part of the design and implementation process.
Green Upgrades Coverage
An endorsement may be added to your insurance policy that provides additional coverage for a vegetated roof, solar panels or other “green upgrades” to your building. This may be referred to as a “green upgrades endorsement” or a “green building endorsement”.
The benefits of green upgrades coverage is that the terms reflect that a green roof may be part of a larger strategy, such as a LEED certification, and that a property claim may require additional expenses such as an architect or engineer or commissioning after a loss.
The example above shows how a green upgrades endorsement considers the additional costs associated with a green roof in the event of a property claim.
As described below, depending on where you are located, there are additional insurance considerations that accompany the decision to install a green roof.
Before Hiring a Green Roof Contractor or Solar Panel Contractor In NYC
In an effort to reduce carbon emissions, Local Law 92 and Local Law 94, the green roof and solar roof mandates in New York City, require that the roofs of certain buildings be partially covered with green roof or solar photovoltaic electricity generating systems in accordance with the New York City Building Code.2
At its most basic level, a roof functions to provide protection from the elements. For many buildings, a roof may provide space for mechanical systems and other building services or might provide outdoor space for recreation and respite.
However, as building roofs evolve to reduce the carbon emissions of a building, additional insurance, contractual indemnification and risk transfer considerations are necessary.
Because green roofs or solar PV roofs are accessed more often than a conventional roof, vegetated/solar roofs add incremental risks to building owners. These include risks such as falls from heights, falling objects or other gravity-related incidents, that can happen when contractors or maintenance people go up onto roofs for installation and/or maintenance purposes.
In New York, New York Labor Law 240/241, also referred to as the “scaffold law” imposes strict liability on contractors and building owners involved in any construction projects involving a height differential.
Property and general liability insurers are well aware of this and often exclude coverage for “action over” related claims… As such, you must analyze the insurance policies of your green roof or solar contractor and the contractual language in the installation agreement with these contractors before proceeding with any work.3
Summary
At the end of the day, a green roof can be an asset to your building that provides many benefits. Just be aware of the potential downsides and make sure that green or vegetative roofs are properly covered and not excluded from your property policy.
If you are building a commercial green building, or engaged in a green building certification process, you can also ask for a special endorsement called a “green upgrade endorsement” or “green building insurance endorsement”.
There are liability factors to consider in your green roof choices as well. Check your legal and insurance contracts for downstream indemnification and strong liability coverage in your favor before agreeing to hire a green roof or solar contractor.
Footnotes
- The Heat Island Group, an organization that concentrates on the study and development of more reflective surfaces for roadways and buildings, has monitored buildings in Sacramento with lightly colored, more reflective roofs. The group found that these buildings used up to 40% less energy for cooling than buildings with darker roofs. The Florida Solar Energy Center performed a similar study, also showing up to 40% cooling energy savings.
- Also, in New York City, all roofs must be cool roofs, with some exceptions – meaning the materials must meet solar reflectivity requirements.
- An action over claim is one where the employee of a contractor or sub-contractor is injured on the job, files a workers' compensation claim, and also sues the building owner for negligence.
