Building green: Green roofs have a head start

If your customers are looking to build green, local building codes can be major roadblocks to their plans. However, one type of green construction seems to be getting better traction in urban building codes. Namely, the green roof.

According to a recent article in the Construction Dive, there are all sorts of municipal regulations that contradict green building techniques thus preventing the average homebuyer from building the green-home-of-their-dreams.

Net Zero hurdles

Homebuyers wishing to go “net zero” for example, need to have what can be described as a “super-insulated” home, with insulation installed on the exterior of the building up to a foot thick. This can come into conflict with municipal building setback requirements.

Another characteristic of “net zero” construction is extreme climate control by making the building “airtight” and relying exclusively on HVAC to move air in and out of the structure, greatly increasing its energy efficiency. This can run against minimum ventilations required in codes that are designed around more traditional buildings.

Furthermore, some municipalities and local homeowner associations have specific rules about aesthetics that could rule out any kind of solar panel installation.

Meanwhile, many forward-thinking municipalities are favoring the green roof. This consists of a roof partially or completely covered by vegetation and can include a drainage or irrigation system.

Green Roof Programs

Cities such as Chicago, Baltimore, Seattle, Washington D.C., Portland and Austin all have green roof programs. Some of them throw in incentives such as a certain amount of money per square foot of green roof installed (Baltimore, Portland) or extra-allotted floor space for each square foot of green roof installed (Austin).

Green roofs Philadelphia

©Recover Green Roofs

Green Roof Benefits

Green roofs got a head start on other green technologies. This is because they profit the building owner and the municipality as well. Green roofs help reduce a city’s heat load (urban heat effect). They also help better manage storm water by absorbing up to 50% of the rainfall they receive. Vegetation is also a natural air filter and can help counter urban air pollution.

Green roofs have other benefits. They can reduce a building’s interior temperature by 6 to 8 degrees Fahrenheit. Potentially, they can reduce air conditioning costs by 8%. They will even help reduce food bills when used for gardening.

A green roof adds significant weight to a structure. It, therefore, requires careful load calculations if included in a design. Loads on both the horizontal and vertical members must be considered. Green roofs between 2 and 6 inches thick can increase roof load by 14 to 35 pounds per square foot.

If your are considering such an architectural feature and would need to know about Open Joist Triforce load capabilities, download our spec guide or contact us

Triforce Spec Guide

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