What is Green Roofing?

Updated: Aug 14, 2020

When asking “how can I reduce energy costs” for your property, you might want to consider a green roof system. With rising energy costs and the movement towards eco-consciousness, the increasing popularity of green roof installation is a no brainer. According to the US Department of Energy, the average American household releases about 2 tons of carbon dioxide into the atmosphere, while homeowners spend upwards of 11 billion dollars a year to cool their homes. Los Angeles and Orange county homeowners especially have the challenge of keeping costs down in a hot climate. As the world becomes increasingly mindful of its carbon footprint, more and more property owners are implementing construction methods and materials that have a more positive environmental impact.

Green roof systems are classified as: protective coatings, reflective membranes, garden systems, slate, metal, tile, concrete, and photovoltaic. Here are three main types of green roofing systems that can have a large impact on your energy consumption and costs.

Reflective Roof Coatings

A reflective roof coating or white roof is the best known and most applied of all green roof systems. These systems reduce roof temperatures by reflecting the sun's rays and are great for almost every application, including residences, apartment buildings, condominiums, townhouses, retail buildings, hospitals, schools, malls, and hi-rises.

White roof systems involve applying a fluid directly onto the roof. A superior acrylic roof coating (waterproofing component) and a super tough polyester-mat (reinforcement component) are normally used. Compared to most re-roofing alternatives, this system provides an efficient, high-quality solution at a fraction of the cost.


  • Safe to Apply: The roof coating is applied at ambient temperature, eliminating the possibility of injuries from 500 degree asphalt and fires caused by overheated kettles or torches.

  • Odorless: Acrylic roof coatings have no odor, unlike melted asphalt or tar.

  • Lightweight: The system’s light weight allows application over the original roof with a minimal weight increase: 40 lbs per 100 square foot, as opposed to 175 lbs per 100 square feet for a cap sheet, and 500 lbs per 100 square feet for a gravel roof.

  • Strong and Flexible: Over 300% stronger than fiberglass or organic roofing felts, acrylic roof coatings retain their structure and flexibility.

  • Lower Temperatures: White acrylic roof coatings protect the roof from UV deterioration, reflecting solar heat from the building interior, thereby reducing energy consumption, maintenance, and utility costs.

  • Low Waste and Pollution: Because there is no need for tear-off and the system is applied at ambient temperature, it does not contribute to landfill or air pollution.

  • Cost Effective: This system can be expensed as maintenance, rather than capitalized over years like a conventional roof.

Garden Roofs

When researching how you can add to your existing roof, you may have asked “what is a green roof” or “how does a green roof work.” Garden roofs, also known by the general term “green roofs,” help mitigate the consequences of displacing naturally occurring vegetation with heat-absorbing materials like concrete and asphalt. Like many large cities, Los Angeles and Orange County suffer from what is called the Urban Heat Island effect (UHI), an issue that can be alleviated by green roofs.

Garden roof development involves the creation of "contained" green space on top of a human-made structure. Utilizing an abundant, often unused surface, a garden roof system is an extension of the existing roof which involves high quality water-proofing, root repellent system, drainage system, filter cloth, a lightweight growing medium, and plants. Garden roofs are valued for their contribution to biodiversity through implementing native flora and sustaining a variety of animals and insects.

Across both private and public sectors, green roof technologies not only provide the owners of buildings with a proven return on investment, but also represent opportunities for significant social, economic, and environmental benefits, particularly in cities.


  • Energy Efficient: Greater insulation can reduce the amount of energy needed to moderate the temperature of a building.

  • Increased Roofing Membrane Durability: Garden roofs decrease the exposure of waterproofing membranes to large temperature fluctuations and UV radiation which can cause micro-tearing and deterioration.

  • Fire Resistant: These roofs have much lower burning heat load than do conventional roofs.

  • Stormwater Management: Water is stored by the substrate and then taken up by the plants where it is returned to the atmosphere through transpiration and evaporation. These systems also redirect water away from the roof structure thus avoiding water damage.

  • Improved Air Quality: Plants on green roofs capture airborne pollutants, and their temperature-moderating effects can reduce demand on power plants, thus potentially decreasing the amount of CO2 released into the atmosphere.

  • Aesthetic Improvements: Urban greening has long been promoted as an easy and effective strategy for beautifying the built environment and increasing investment opportunity.

  • Moderation of UHI: Plants are able to cool cities during hot summer months and reduce the Urban Heat Island effect through UV absorption and by covering some of the hottest surfaces in the urban environment - black rooftops.

  • Marketing: Garden roofs can increase a building's marketability as an identifiable part of the green building movement.

Photovoltaic Roof Systems

Photovoltaic (PV) roofing systems involve solar cells and panels that channel sunlight and convert it into electricity, thereby producing energy savings. California offers rebate programs for local businesses and residential homeowners interested in having PV systems installed on their roofs. The Los Angeles Department of Water and Power offers solar incentives and is one of the largest programs of its kind in the nation.

It is estimated that California alone is the third largest consumer of solar powered applications in the world. Another benefit of using a solar roof system is that they can collect and heat your hot water for even more cost savings over the lifetime of the roof.

Powered by solar energy instead of electric attic fans, an attic’s temperature can be lowered by 50%, which can save a homeowner or business owner up to 30% on their air conditioning costs alone during the hottest times of the year.

Currently, there are two main types of PV systems: amorphous and crystalline silicon systems. These systems have an average life expectancy of more than 30 years.

  • Amorphous systems are 9 percent efficient, with a flexible, thin film installed directly over the membrane.

  • Crystalline systems are 34 percent efficient and are also installed over the membrane.

New PV technology called flexible thin film is also on the horizon. Palo Alto company Nanosolar uses pliant sheets of foil for their panels, which can be molded onto roof shingles. More attractive and less costly than traditional solar panels, experts say this product could produce electricity for about the national average of 10.4 cents per kilowatt-hour. While these roofs may cost more than a conventional roof, the significant savings over a 30-year period makes it well worth the money spent as this roof system will pay for itself in a very short time.

Green roofing systems are becoming more and more popular as their benefits become increasingly apparent to home and property owners. Many of these systems are low maintenance, offer substantial energy savings, and are a smart investment for homeowners and businesses. While you consider what type of roof will work best for your property, contact us for a professional inspection and free roofing estimate on any work or repairs that may be required. Call us today at (310) 903-0536 to schedule an inspection and determine the right materials and services for you.

Southland Roofing Inc. is committed to providing premier service at the right price. Serving Los Angeles and Orange County, we pride ourselves on safety, efficiency, and competitive pricing as we revolutionize the roofing industry. Contact us today to find out how we can serve all your roofing needs.

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