When you own a commercial facility, the temperature your roof climbs up to can be an extremely important piece of information. Why? Because it has a direct influence over the temperature inside your building. When your roof gets blazing hot, it emits heat into your building that your air conditioner or cooling system will struggle to keep up with. Thus, having the wrong type of roof could actually mean a far greater expense in terms of energy needed to keep your roof cool.
Temperatures of Various Roof Types
Different types of roofs have different surface temperatures because they’re made of different things. Some roofs are particularly good at staying cool during summer, while others are definitely not. Knowing this can help you make the right choice for your facility the next time you have to replace your roof.
Here are a few of the most common materials and how hot they can get. Note: all temperatures are in Fahrenheit, and are results for tests taken on a 90-degree day, conditions which are often light compared to some of the hottest days in the middle of an Arizona summer.
- Black roof: A black roof is any type of roof that’s topped with tar, rubber, or any other black-colored material. These are some of the worst roofs to use during summer months because the black color absorbs almost all of the sun’s radiation and converts it to heat, which it then re-releases into the atmosphere. Black roofs are particularly hot for buildings below them, and tend not to last in areas with high amounts of sunlight and heat, like the Arizona desert. It also doesn’t help that they can reach surface temperatures of anywhere from 140 to 190 degrees.
- Gravel: A gravel roof is the more common name for a “built-up roof,” a roof consisting of different layers of tar and other materials built up into a durable membrane that’s topped with a layer of gravel. These are pretty common in flat roof applications, and while many people think the tar layers are not great for heat, the truth is they’re quite a bit cooler than black roof alternatives: they generally run anywhere from 125 to 140 degrees, and transfer less of this heat to your indoor space.
- White roofs: A white roof, usually TPO, PVC or some other form of a membrane roof, is one of, perhaps the best roof material to use in an Arizona summer. White roofs do the opposite of black ones—rather than absorbing light energy and converting it to heat, these roofs instead reflect the light back into the atmosphere, preventing it from becoming thermal, which keeps them cooler and even rejects more heat from outside. It should then come as no surprise that these roofs tend to run anywhere between 102 and 120 degrees.
So which material is best for you? White roofs may seem like the obvious winner—they stay 50 degrees cooler or more than their black roof counterparts, and around 30 degrees cooler than their gravel counterparts. That’s huge savings when it comes to keeping heat out of your building. However, membrane roofs have their upsides and their downsides as well, which makes it important to carefully consider what your plans are for your roof when determining which is right for you.
At Lyons Roofing, we like to strongly recommend polyurethane spray foam roofs for commercial purposes. These roofs have a number of benefits that make them ideal for a flat roof in the Arizona climate. For starters, their white color makes them resistant to a lot of heat, and that could help you save a bundle on your energy costs. However, the nature of the polyurethane material is also beneficial. Polyurethane is a closed-cell foam, which means that they literally trap air in tiny cells throughout the material. This air requires significantly more energy to heat up, which means these roofs naturally resist temperature changes. So while a typical white roof may run anywhere from 102 to 120 degrees, polyurethane roofs tend to be on the low end of this spectrum, or potentially even lower!
If you need your roof replaced, talk with the experienced Tucson commercial roofing experts from Lyons Roofing and find out more about the various types of commercial roofs we offer to see which is right for you. Contact us by calling (520) 447-2522 to schedule a consultation.