Cool Tips for Hot Roofs, Part I
The Houston population is booming, and newcomers from cooler locations are pouring into the city. Those of you from up north likely don’t realize that building styles and materials are different down here, especially in the areas of roofing. Here, the emphasis is on insulating to keep the cool in and the hot out, rather than the heat in during the winter months. Roofs in Houston must face temperatures that reach triple digits in the summer, so they’re built for reflectivity rather than absorption using.
Are you a Houston newcomer curious about the best ways to keep your home cool? Read on and we’ll help you out.
Why Do Roofing Materials Matter?
Have you ever sat in a car with a black leather interior on a hot day? If you’re wearing shorts, your legs are burning and sticking to the seat. Not a pretty picture, to be sure, but this type of car interior will absorb and hold the heat rather than dispersing it. Your roof works the same way: Regular roof tiles are often made using a felt-like material covered with tar and asphalt. This dark tile absorbs heat, and the cloth material holds the heat and pushes it down into the building. This method is great in cold areas — it takes the sparse winter sunlight and absorbs and retains it. But in areas like Houston, it makes a home like an Easy Bake oven.
Have you ever noticed that many of the roads and buildings in the Houston area are light colored rather than black tar and dark colored? The reason is that cities can reduce the temperature of the building by using lighter colored materials, especially the roofs, as these reflect the sun’s rays. The former United States Energy Secretary stated that painting roofs white can help fight global warming.
“Cool roofs are one of the quickest and lowest-cost ways we can reduce our global carbon emissions and begin the hard work of slowing climate change,” said former Energy Secretary, Stephen Chu, in July 2010, while announcing that Department of Energy buildings would be painted white wherever possible.[source]
The roof of your home is the first level of protection you have against the brutal sun — and buying the right type of heat reflecting roofing saves both initial costs and energy costs. You can have a great air conditioning system, but if your house is absorbing and holding heat, your energy bills will be astronomical.
Creating a Barrier
If you have a traditional roof tile on your home, don’t get the claw hammer and rip it off just yet. There are a number of ways to cover up your roof, like foam sprays, ceramic-based paints, recycled cooking oil, and elastomeric sealants. These coverings create a barrier between your existing roof and the sun to keep your home cool. In the roofing industry this technique is referred to as Built Up Roofing or BUR.
Another way to deal with heat buildup in roof tiles is to add a radiant barrier. A radiant barrier can be something such as a sheet of aluminum roof or even a reflective spray. It creates an effective barrier between the roof and the interior of the home without the need to remove the existing roof. The National Association of Home Builders estimates that the addition of a radiant barrier can cost anywhere from fifteen to seventy-five cents a square foot, but that a home owner can save up to $200 a year in energy costs.
No matter what type of roof you choose, the right kind of insulation is essential. If you are buying a home, check to make sure that the roof is the same temperature as the outside air, as this is a sign of a well-insulated house. Have a professional look at the intake and outflow vents to be sure that the air flow is moving correctly around your roof. A properly insulated roof will keep the hot air out and the cool air in the interior of your home.
Barriers and insulation will help keep heat out of your house, but the right roofing materials are important too. Stay tune for Part II to learn about the different types of roof tiles available in hot weather regions and the advantages and disadvantages of each.