As the Green Roof industry grows, we are finding more instances where people reject the idea of a green roof on their building due to a lack of information (or misinformation). So here at Sow Green, we are setting out to combat some misconceptions about green roofs with a series of articles debunking the most common myths.
Myth #2: Green Roofs are Too Expensive
Although green roofs do cost anywhere from $10-25 per square foot, they are not more expensive than traditional roofs overall, and there are several reasons why.
Green roofs last longer than traditional roofs. In fact, they often last two times as long, if not more. This is because the layers of soil, root barriers, and vegetation protect the waterproofing membrane of a roof from UV, hail, wind, and other damage. Therefore, you don’t have to replace or retrofit your roof as soon (which can save you a lot of money in the long run).
You also save money on heating and cooling costs. Black roofs often get hot in the summer by absorbing the sun’s rays, which often makes buildings hot too. Thanks to a nifty natural process called evapotranspiration, the vegetation on a green roof can make the ambient temperature above the roof at least 6 degrees cooler. It also insulates the roof, keeping cool air from your A/C or heater inside. This is especially true in winter since warm air rises, many buildings often lose heat through their roofs. But with a green roof, you don’t have to use as much energy to climate control the building, so you save money. How much money varies depending on the type of green roof and the insulation of the rest of the building. And finally, with an increasing amount of volatile weather and many cities experiencing extreme flooding, stormwater management costs are at an all-time high. This is because urban development in major cities is created more surfaces laden with concrete and steel instead of soil and trees. But green roofs reduce the amount of stormwater a building has to treat because the soil and vegetation soak it all up (and in many cases can reduce pollution runoff). So not only are you reducing the impact your building has on the natural environment, but you’re saving money in the long term on stormwater fees. Many cities even have programs that give a reduced rate to buildings with vegetative roofs or permeable surfaces like brick parking lots.
Although it is important to do a cost-benefit analysis before embarking on any large scale project, many green roofs offer long-term advantages. Like with many other sustainable projects, green roofs are a little more expensive upfront but can give you big savings in the long run, and therefore should be treated as a sound investment instead of a financial burden.