Top 10 Roofing Materials for Hot Climates

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Homeowners know that roofing materials play a crucial role in maintaining a cool indoor environment, particularly in warmer climates. The sun’s rays can be absorbed or released by a building’s roof, making it the first line of defense against heat. One way to visualize this is to think of sitting on a black fabric-covered chair versus a metal, clay, molded plastic, or slate chair. The former will absorb and store heat, while the latter will reflect it away. Similarly, roofing tiles made of felt-like materials overlaid with asphalt and tar will hold and transfer heat, while other types of roofing will reflect light and heat away from the building. The color and type of roofing materials can affect the heating and cooling of buildings and even entire cities. In fact, the US Energy Secretary suggested that painting roofs and roads white could reduce the costs of running air conditioning by up to 15%. However, before jumping to such a drastic measure, it’s worth considering the following top 10 roofing materials and techniques that have proven to work well in hotter climates.

10: Overlays and Radiant Barriers

Cool-roof coatings have advanced in recent years, providing ways to cool existing roofs by applying coats of overlay that reflect heat away. These include elastomeric sealants, foam sprays, ceramic-based paints, and even recycled waste cooking oil treatments. Built Up Roofing (BUR) is one method for applying cool-roof surface coatings over traditional asphalt or tar roofing. However, ease of application, durability, and energy savings vary by manufacturer. Consulting with a local roofing contractor and checking local building codes can help determine what works well in different regions. Another technology is a roof underpinning or sub-roof system called a radiant barrier. This involves installing a reflective material, such as aluminum, or even a specialized reflective spray treatment that’s installed into an attic or space between a home’s interior and the roof. The barrier keeps heat up and out of a home, potentially saving homeowners up to $200 annually, depending on the region.

Oil Slick

A new type of roofing spray made from recycled cooking oils may soon be available, according to the American Chemical Society. Similar to a cooking spray, this innovative spray will cool roofs during hot weather and capture heat during cold weather. However, it is uncertain when this product will become available [source: Raloff].

9: Slate Tile


Slate tile has been used for roofing for centuries and is a European tradition that was introduced to the Americas in the 17th century.
ŠiStockphoto.com/Michaela Fehlker

Slate roofing is known for its durability and natural color range, making it a popular choice for roofing. Light colored and earth-toned slate can help to reduce heat absorption during hot weather due to its reflective properties. Over time, slate wears to a nice finish and requires minimal maintenance. However, slate is a heavy and expensive material, making it less practical than other options. While it is popular in hot climates, slate can be expensive in areas where it is not readily available. Although reclaimed or salvage slate is available, installation and transport costs can be high [source: Sweetser].

8: Terra Cotta and Clay


Terra cotta and clay tiles are popular in areas with lots of sun and heat and are known for their ability to keep buildings cool.
ŠiStockphoto.com/Ivan Ivanov

Traditional terra cotta and clay tiles are commonly found in regions like Spain, Mexico, Italy, and the American Southwest due to their abundance of heat and sunshine. These tiles are light in color and do not absorb as much heat as darker roofs. They are also shaped in a way that allows for air and water circulation and runoff, keeping the building below cool. Modern clay tiles often have paint treatments to make them look like more expensive materials such as slate or traditional terra cotta while also providing weatherproofing and reflective capabilities. However, terra cotta and clay tiles can be heavy and require a solid foundation for load-bearing and wind and earthquake resistance. Cold and wet weather can also cause tiles to snap, so it is important to check for durability and temperature resistance [source: Sweetser].

7: Concrete Tiles in Cool Colors

Concrete tiles are a durable roofing option that is less expensive than slate and clay but more costly than traditional shingles. They are heavy and take a long time to heat, making them ideal for warm weather roofing. Poured concrete slab roofing is a low-cost option in developing countries, providing protection from bad weather and pests. It also acts as a barrier layer under more cosmetic roof treatments in developed countries. Concrete tiles are easier to install than poured concrete and are fireproof and solid. They can also take in color when dyed, with specialized “cool colors” increasing energy efficiency by reflecting more of the sun’s rays.

Concrete tiles are made from sand, water, and cement, with the baking process toughening the material to withstand rain, heat, and wind. Some concrete tile roofs in Europe and elsewhere have lasted over 150 years and still function as originally designed. Installers should consult minimum code requirements for environmental conditions by region, with extra steps and precautions required in areas like Florida to meet hurricane-force wind resistance requirements.

6: Green/Living Roofs

Dense areas with concentrations of dark asphalt roofs, parking lots, and roadways create a negative environmental effect called a “heat island effect” or “urban heat island effect.” To combat this, green or living roofs incorporate a waterproof membrane filled with soil and vegetation that cools naturally through soil temperature and greenery growth. These roofs also release oxygen into the air, making it less toxic and harmful than traditional shingle roofs. Water runoff cools the buildings and protects the base roofing underneath, adding to roof longevity.

Green roofs have been keeping buildings cool for decades in modern Europe, with Germany leading the way in publishing a green roofing guide. However, higher costs and a lack of expertise and vision are likely to slow their growth. Italian architect Renzo Piano is a high-tech green pioneer, incorporating solar and green roofs into his designs, as well as non-traditional insulation made from recycled denim.

5: Solar/Photovoltaic Systems

To store heat and use it for alternative energy requires a different approach than simply reflecting it back into the atmosphere. Photovoltaic or PV roof shingles offer an ideal solution. They capture solar power and convert it into electricity, which can be used in your home or office. These shingles come in traditional shapes and sizes, making it easy to incorporate this energy-efficient technology without sacrificing aesthetics. However, cost and location can be major factors. Although the usage of photovoltaic shingles and sheets will eventually lead to lower prices and increased performance, the initial investment in products and installation is high. In addition, the amount of solar energy power generated is dependent on the number of sunny days per capita. Therefore, cities like London and Seattle may not be able to harness solar energy as effectively as sunnier locales like Phoenix or Athens, Greece.

4: “Rubber” Membrane Roofing

While a rubber roof may not seem like the best option for warm climates, a single-ply membrane roofing made of thermoplastic or synthetic rubber called EPDM can be a great choice. EPDM is a common roof coating in commercial buildings due to its long-lasting, weather-resistant properties. It is available in sheets or rolls and is applied in almost seamless layers, providing a waterproof barrier. Thermoplastic coverings are another option that are also weather-proof and wear-resistant, with reflective coating options. They are more malleable and can be reset with heat for roofing a more sloped surface. Both types of membrane roofing are lightweight, durable, and reflective, making them ideal for keeping the sun from absorbing into structures. They are also good foundation layers for green roofing.

3: White Barrel “S” Tile

White s-shaped tiles made of concrete are an effective option for keeping heat out of homes in hot and humid conditions. Tests conducted by the Florida Power & Light Company showed that these tiles reflect about 74% of the sun’s energy away from the roof. They resemble traditional terra cotta designs and take advantage of the same raised arch design that allows for air circulation. S-shaped concrete tiles in bright white reflect more solar rays than traditional terra cotta, by about 40%.

2: White Flat Tile

Flat concrete tiling is another great option for warm climates, and is available in cool colors. Bright white flat tiles made of ceramic, elastomeric material, or a combination of fibers and cement are highly heat-reflective and long-lasting. They reflect as much as 77% of the sun’s rays, keeping heat from filtering down into buildings. Like the white barrel tile, white flat tiles are an effective solution for keeping homes cool in warm climates.

Maintaining white roofing, like most types of roofing, requires some upkeep. Power-washing can help prevent the surface from becoming dirty and losing its reflective quality compared to traditional shingles.

1: White Metal Roofing


White metal roofing cools faster at night and retains heat for shorter periods compared to other roofing types. However, it doesn’t reflect as much of the sun’s energy away from the roof as white flat and white barrel tiles, reflecting only about 66% [source: Better Homes and Gardens]. Despite costing 20-30% more than traditional roofing, metal roofing is an overall cost-saver due to its energy efficiency, durability, and low maintenance needs [source: Metal Roofing Alliance]. Proper installation and treatment are necessary to maximize the benefits of metal roofing in warm climates. Most metal roofs are made of steel and aluminum, with copper options being more expensive. They should also be treated for corrosion resistance and meet code standards for wind resistance and placement. Improper installation without slope planning and glare consideration can cause nearby residents and drivers to be blinded by reflected light, regardless of how cool the white metal roof may be.

Additional Information

Related Articles

  • What exactly is a green roof?
  • Can the installation of a green roof save you money?
  • How do Rubber Roofs function?
  • How do Roofing Materials function?
  • How do Concrete Roofs function?
  • What is the urban heat island effect?

Useful Links

  • Roof Savings Calculator
  • Cool Roof Rating Council

Sources

  • Barringer, Felicity. “White Roofs Catch On as Energy Cost Cutters.” New York Times. July 29, 2009. (Dec. 31, 2010)http://www.nytimes.com/2009/07/30/science/earth/30degrees.html
  • Better Homes and Gardens. “Save Money with the Right Roof.” 2011. (Jan. 2, 2011)http://www.bhg.com/home-improvement/exteriors/roofs/save-money-with-the-right-roof/
  • California Academy of Sciences. “About the Building: The Architect as Explorer.” 2011. (Jan. 7, 2011)
  • http://www.calacademy.org/academy/building/index.php
  • California Energy Commission, Consumer Energy Center. “Frequently Asked Questions about Cool Roofs.” 2011. (Jan. 7, 2011)http://www.consumerenergycenter.org/coolroof/faq.html
  • Cool Roof Rating Council. “What’s So Cool About Cool Roofs?” McGraw-Hill Construction Continuing Education Center. March 2009. (Jan. 7, 2011)http://continuingeducation.construction.com/article.php?L=68&C=488&P=1
  • Connor, Steve. “Obama’s Climate Guru: Paint Your Roof White!” The Independent. May 27, 2009. (Jan. 6, 2011)http://www.independent.co.uk/environment/climate-change/obamas-climate-guru-paint-your-roof-white-1691209.html
  • Encyclopaedia Britannica. “Roof.” Encyclopaedia Britannica Online. 2011. (Jan. 2, 2011)http://www.britannica.com/EBchecked/topic/509178/roof
  • EPDM Roofing Association (ERA). “EPDM As a Cool Roof.” 2011. (Jan. 2, 2011)http://www.epdmroofs.org/cool-roofing/
  • International Association of Certified Home Inspectors (InterNACHI). “Roofing.” 2011. (Jan. 2, 2011)http://www.nachi.org/roofs.htm
  • Lawrence Berkeley National Laboratory. “Cool Roofs for Hot Climates.” U.S. Department of Energy, Home Energy Saver. 2010. (Dec. 31, 2010)http://hes.lbl.gov/consumer/help-popup/content/~consumer~nrr~cool-roofs
  • Levinson, Ronnen. “Cool Roof Q&A.” Lawrence Berkeley National Laboratory. July 29, 2009. (Jan. 7, 2011)coolcolors.lbl.gov/assets/docs/fact-sheets/Cool-roof-Q%2BA.pdf
  • Metal Roofing Alliance. “Frequently Asked Questions.” 2011. (Jan. 7, 2011)http://www.metalroofing.com/v2/content/about/faq.cfm
  • Miller, Charlie. “Extensive Green Roofs.” Whole Building Design Guide. June 11, 2010. (Jan. 6, 2011)http://www.wbdg.org/resources/greenroofs.php
  • National Association of Home Builders Resource Center. “Radiant Barriers.” Toolbase.org. 2011. (Jan. 10, 2011)http://www.toolbase.org/Technology-Inventory/Interior-Partitions-Ceilings/radiant-barriers
  • National Park Service (NPS). “From Asbestos to Zinc: Roofing for Historic Buildings: Concrete Roofing Tile.” Mar. 19, 1999. (Jan. 6, 2011)
  • National Trust for Historic Preservation. “Roofing Links and Resources.” 2011. (Jan. 5, 2011)http://www.preservationnation.org/issues/weatherization/resources/roofing.html
  • Oak Ridge National Laboratory. “Radiant Barrier Fact Sheet.” 2011. (Jan. 6, 2011)http://www.ornl.gov/sci/ees/etsd/btric/RadiantBarrier/index.shtml
  • Oak Ridge National Laboratory and Lawrence Berkeley National Laboratory. “Roof Savings Calculator.” 2010. (Dec. 31, 2010)http://www.roofcalc.com/index.shtml
  • Raloff, Janet. “Cool Roof Coating: Mechanism Kept Under Wraps.” ScienceNews.org. Mar. 21, 2010. (Jan. 6, 2011)http://www.sciencenews.org/view/generic/id/57485/title/Cool_roof_coating_Mechanism_kept_under_wraps
  • ScienceDaily.com. “New ‘Smart’ Roof Reads the Thermometer, Saves Energy in Hot and Cold Climates.” Mar. 31, 2010. (Dec. 31, 2010)http://www.sciencedaily.com/releases/2010/03/100321203506.htm
  • Sweetser, Sarah M. “Roofing for Historic Buildings.” National Park Service: Preservation Briefs. February 1978. (Jan. 2, 2011)http://www.nps.gov/history/hps/tps/briefs/brief04.htm
  • Urban, Bryan and Roth, Kurt. “Guidelines for Selecting Cool Roofs.” U.S. Department of Energy Building Technologies Program. July 2010. (Jan. 6, 2011)www1.eere.energy.gov/femp/pdfs/coolroofguide.pdf
  • U.S. Department of Energy “Deciding Whether to Install a Cool Roof.” USA.gov. Oct. 20, 2010. (Dec. 31, 2010)http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10096
  • U.S.

    The Department of Energy, U.S. Environmental Protection Agency, U.S. News & World Report, and Cathy Zoi have all provided information on energy-saving roof products. Radiant barriers, ENERGYSTAR roof products, smart roofs, and cool roofs are all discussed in these sources. Links to the original articles are provided in the HTML code.

    FAQ

    1. What are the best roofing materials for warmer climates?

    The best roofing materials for warmer climates are those that reflect sunlight and heat, and have good ventilation. These materials include metal, clay, concrete, and asphalt shingles. Metal roofs are the most popular choice as they are durable, energy-efficient, and can last up to 50 years.

    2. What are the advantages of metal roofing for warmer climates?

    Metal roofing is a great option for warmer climates as it reflects sunlight and heat, keeping the interior of the house cool and reducing energy costs. Metal roofs are also durable and can withstand high winds, rain, and hail, making them a good choice for areas prone to severe weather.

    3. Are clay tiles a good option for warmer climates?

    Clay tiles are an excellent option for warmer climates as they have natural insulation properties, keeping the house cool in hot weather. They are also durable and can last up to 50 years with proper maintenance. However, clay tiles are heavy, and the roof structure may need to be reinforced to support their weight.

    4. What are the benefits of concrete roofing for warmer climates?

    Concrete roofing is an excellent option for warmer climates as it is durable, energy-efficient, and fire-resistant. Concrete tiles can also withstand high winds, rain, and hail, making them ideal for areas prone to severe weather. They are also available in a variety of colors and styles, allowing homeowners to customize their roof to their liking.

    5. Can asphalt shingles be used in warmer climates?

    Asphalt shingles can be used in warmer climates, but they are not the best option. They absorb heat, making the interior of the house hotter and increasing energy costs. However, if homeowners choose to use asphalt shingles, they should opt for lighter colors that reflect sunlight and heat.

    6. What are the downsides of using wood shingles in warmer climates?

    Wood shingles are not the best option for warmer climates as they absorb heat and can become damaged by prolonged exposure to sunlight. They are also prone to mold and mildew growth in humid environments, which can lead to rot and decay. Additionally, wood shingles are not fire-resistant, making them a poor choice for areas prone to wildfires.

    7. Is slate a good option for warmer climates?

    Slate is an excellent option for warmer climates as it is durable, fire-resistant, and can last up to 100 years with proper maintenance. It also reflects sunlight and heat, keeping the interior of the house cool and reducing energy costs. However, slate is heavy and may require additional roof support.

    8. Can green roofs be used in warmer climates?

    Green roofs, also known as living roofs, can be used in warmer climates, but they require careful planning and maintenance. They consist of a layer of soil and vegetation, which helps to absorb heat and reduce energy costs. However, they also require regular watering and pruning to prevent plant overgrowth and ensure proper drainage.

    9. Are solar panels a good option for warmer climates?

    Solar panels are a great option for warmer climates as they can generate electricity from sunlight, reducing energy costs and carbon emissions. They can also provide shade to the roof, reducing heat absorption and keeping the interior of the house cool. However, they are expensive to install and require regular maintenance.

    10. How can homeowners choose the best roofing material for their warmer climate?

    Homeowners should consider several factors when choosing the best roofing material for their warmer climate, including energy efficiency, durability, and resistance to severe weather. They should also consider the cost, weight, and aesthetic appeal of the material. Consulting with a professional roofing contractor can help homeowners make an informed decision based on their specific needs and budget.

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