Cities and communities across America are looking for ways to cut utility costs and improve air quality. The emergence of the living roof-- a roof finished with plants instead of asphalt, slate, or wooden shingles-- may hold part of the answer for improving the environment with professional roofers.
Why A Living Roof?
A living roof has many pros, and very few cons:
1. It reduces the heat island effect. Finished materials, like roads, parking lots, and roofs, have dark asphalt surfaces which retain heat. In urban places, all of this retained heat drives up the air temperature, which leads to more use of artificial cooling systems, which leads to more electricity use, which leads to more waste heat, which increases the air temperature. As cities grow, this cycle only gets worse.
A living roof does not store and absorb heat. The plants on the roof use sunlight to make food through photosynthesis, and they are always releasing water into the air, which can act as a coolant during times of warmth.
2. It improves air quality. Plants breath carbon dioxide and exhale oxygen. They purify the air just by being alive. The more green roofs in an urban space, the better the air quality will be.
3. It keeps the house cool. Just having a garden on a rooftop space can help a roof to be more energy efficient. Many roofing materials absorb heat from the sun, which can elevate cooling costs inside. The plants offer insulation and moisture, which are an effective environmental insulation against heat transfer. One study showed the a green roof could reduce air conditioning use by 75%.
4. It reduces waste. Living roofs are installed with several protective layers to make sure that the moist plant environment doesn't translate to leaks and mold problems inside. These layers also protect the integrity of the underlying roof; whether the base roof is metal, clay, or cement, it will last much longer under the protection of the rooftop oasis. A roof will need replaced less often, which means fewer materials end up in the landfill.
5. It increases usable space. If a garden is installed on flat roof, it becomes an extra layer of space that people can use. For example, a corporate building could have a living roof designed with tables and even a pavilion for employees to eat lunch outdoors. Businesses could even hold meetings on the roof if need be.
Who Can Build A Living Roof?
Currently, living roofs are best for homes that have flat finishes, or a very slight slope. Homes with steep pitches simply wouldn't be able to create a stable environment for plants.
Also, green roofs are suitable for some residential homes, but they will be most effective for large, commercial buildings, as they have the most contributing flat space in an urban setting. When considering a green roof, it's important to contact a contractor to make sure the building itself can handle the weight of the extra soil, water, and plants.
Do Living Roofs Require Extra Maintenance?
Large-scale roofs will need a few full-time caretakers, but that's not a bad thing. In fact, if just 1% of urban roof space was transformed, it could create up to 190 000 jobs.
To reduce maintenance, it's best to choose plants that have shallow root systems and are hardy during hot weather. Unless the garden is elaborate and large, it will rarely need to be water. The layers below the plants will absorb and store rain water for plants to use. The moisture retained by the prepared layers will be drawn away from the roof by the roots of the plants. During dry spells, some extra watering may be necessary. .