Top Considerations for the Thermal Performance of Commercial Roofing Systems in Nevada
The thermal performance of your commercial property has a significant impact on your total utility costs. A building’s envelope does more than protect against the exterior elements — it also controls the amount of energy that transfers in and out of your structure. As a result, good thermal heating and cooling can help lower energy demand by close to 35%.
In particular, since a roof can represent anywhere from 50-70% of your building’s total enclosure, it has a significant effect on your property’s thermal conditions. About 25% of heat escapes upwards through your roof, and in Nevada, a roof must deal with direct sunlight, key aspects that determine a building’s interior energy balance.
The modern-day property occupant expects comfortable and efficient internal climate controls, so let’s look into how you can improve your thermal performance with roofing system upgrades.
Nevada Climate and Environment Considerations
Any discussion about thermal performance first requires a good understanding of the current climate conditions. You need a roofing system that fits the weather patterns of Nevada, not Northern Alaska. Different environmental loads need different energy transfer solutions.
Nevada is primarily a mix of desert and semi-arid climates. You can expect a lot of sunshine, as cloud cover occurs on average 12% of the time in the summer seasons. With minimal precipitation and summers with high temperatures, it is a dry environment. Any roofing system you use must be able to withstand intense sun exposure, where building materials can become brittle before eroding.
The heat in Nevada is another concern, as the high temperatures can cause roof expansion and shrinkage that leads to cracks and other damage. Las Vegas temperature lows averaged 27 degrees celsius, while highs can reach above 40 degrees plus humidity.
Wind also results from high-pressure systems that come up from the south. And when that wind approaches the mountains, it creates precipitation and more extreme weather patterns. Nevada does have four seasons, so your roof needs durability through the various weather alterations.
Lastly, the low humidity and dry conditions (especially in the southern region) contribute to forest fires. In 2020, over 800 fires burned through the state. Selecting a material with fire ratings that can handle extreme heat is a wise idea.
Thermal Performance and Cool Roofs
Due to the weather conditions in Nevada, your roof’s building material must offer good resistance to UV radiation, have excellent sustainability, and have long-lasting durability to heat and sunlight.
Luckily, there are several ways that a high-level roofing system can help achieve those thermal performance goals. In particular, a cool roof system delivers the high solar reflectance and overall thermal emittance you need. It is an ideal way to better protect against Nevada’s sunny climate.
Let’s look into the key elements of a cool roof and how it helps improve your thermal performance.
Roof Reflectivity
The better your roof can reflect UV rays, the less heat that will transfer into your commercial building. Black retains more heat than white, and for that reason, many people use reflective paint on their roofs. Roofs made with dark-colored material can reach 150 degrees Fahrenheit, while a cool roof will maintain a much more manageable 50 degrees.
Roofing contractors use reflectivity ratings to denote how well your current roof can deflect the sun’s rays away. A cool roof generally has a rating of at least 65%, helping keep your building cool during summer at the peak of sunlight exposure.
Thermal Emissivity
Just as a roof must reflect the exterior sunlight, it must also re-radiate the heat it generates back out into the air. Plus, while it radiates the heat out, it must allow trapped heat indoors to escape. The ability for a roof to release contained energy is known as thermal emissivity. It makes sense: the more heat your building emits, the cooler it stays and the less drag on your cooling systems.
Roof emissivity is given a rating, with 70 – 85% (as in 85% of all heat is re-radiated back out) considered a good level of thermal performance, a feat achieved yet again by a cool roof.
The insulation you use in your roofing system will also have a lot to do with your total thermal emissivity, as the material will frustrate heat as it attempts to alter your internal climate. You can find more details about insulation factors here.
Cool Roofs
Cool roofs themselves are sustainable roofing solutions that meet accepted solar reflectance and thermal emissivity levels set out by the Cool Roof Rating Council and the Nevada Building code section R905. Commonly accepted rates include a solar reflectance of 65+ and a thermal emissivity rating of 85+, though those rates change based on several factors such as roof slope and system age.
As a roof system, the materials used on specific roof slopes are designed to transfer less heat into a building, an ideal choice for the Nevada climate.
Since a cool roof has such good thermal performance, it creates some distinct benefits to Nevada commercial property owners:
- Less energy use and lower utility costs
- Less usage and overall energy drain on internal system
- Reduced pollution and greenhouse gas emission
- Improved internal climate control for better human health and comfort.
- Lower maintenance costs
Recent studies show 40% less energy usage once a cool roof is installed. One study even showed an estimated national savings of $750 million over 11 major American city hubs.
Cool Roof Examples
Cool roofs can be both steep and low-sloped, but most commercial systems in Nevada are low-sloped. If you have a steep-sloped structure, tile, asphalt, and shingles are possible material options, while low-sloped roofs will use the following systems:
- Built-Up Roofing Systems (BUR Systems): BUR systems use layered materials piled together to earn good solar reflectance scores. The exact cooling strategy and layer type will change based on weather conditions (e.g., tar vs. reflective mineral granules)
- Coatings: Ideal for already-built roofs, a variety of special pigmented roof coatings can help improve the thermal performance of an existing roof system you currently have.
- Single-ply Roofing Membranes: Single-ply membranes are prefabricated sheets of thermoplastics. The material is durable, energy-efficient, and has excellent thermal performance.
When installed by a knowledgeable contractor or roofing consultant, each roofing system will help you update your building’s envelope and achieve better thermal performance.
Achieving Thermal Performance With Existing Roof System Conditions
Installing a new cool roof will do wonders for your building envelope. But don’t forget — the maintenance and repair of an existing system are also pivotal to optimizing energy savings and reducing life-cycle costs. You need to have a planned maintenance program in place for your commercial roof to extend the life of your commercial facility.
Contact RoofSource for all your planned preventive and corrective maintenance needs. We can provide an unbiased assessment of the condition of your commercial roof and assist you with finding specifiers and contractors in your area, producing specifications, and reviewing bids to ensure you get the best results.