Sunlight can cause considerable damage to a commercial roof, and the amount of sunlight you have in your area has a great effect on your roof's overall longevity. The two most common types of commercial roofs are built-up roofs and single-ply membrane roofs. They both use organic materials — asphalt on a built-up roof and either EPDM or TPO on a single-ply membrane roof. Ultraviolet light will slowly break down the hydrocarbon chains in these organic materials, eventually causing them to oxidize and break apart — when damaged, you'll notice asphalt chipping or your single-ply membranes cracking.

Since sunlight has such a damaging effect on your commercial roof, it's important to take steps to protect it. You'll help increase your roof's longevity. To learn what options you have for protecting your commercial roof from sunlight, read on.

1. Apply a Roof Coating

The most popular way to improve your commercial roof's resistance to sunlight is to apply a roof coating to its topmost layer. Roof coatings are inexpensive, and they can be applied to both built-up roofs and single-ply membrane roofs. Most roof coatings will last for around a decade before they need to be reapplied.

Roof coatings provide a high resistance to ultraviolet light and infrared light, protecting the roofing layer underneath from being damaged by sunlight. Their resistance to infrared light helps keep your roof cooler, as well, which can help reduce your building's energy bills.

You should note that it's important to select the correct type of roof coating — it needs to be able to adhere to the surface of your roof. If your commercial roof is still under warranty, you also need to make sure that the coating you're using won't void it. A commercial roofing contractor in your area can help you select the right type of coating and apply it to your roof.

2. Use Roofing Granules on Your Built-Up Roof

If your building has a built-up roof, you can help protect its topmost asphalt layer from sunlight by broadcasting roofing granules into the asphalt. Roofing granules are typically made of ceramic, which makes them highly reflective. Like a roof coating, they protect the asphalt underneath from both infrared and ultraviolet light.

Roofing granules are most often broadcast into the asphalt when you have a new built-up roof installed. However, it's also possible to use them on an existing roof by applying a thin layer of asphalt over the roof and broadcasting the roofing granules into it before it cools.

3. Install a Ballasted Single-Ply Membrane Roof

Roofing granules aren't available for single-ply membrane roofs — the membranes panels are produced by a factory, so you don't have any chance to broadcast the granules into them when they're installed.

However, you can achieve a similar effect by installing a ballasted single-ply membrane roof. A ballasted single-ply membrane roof has a thick layer of gravel placed over the roofing panels, and the weight of the gravel holds the roofing panels against the roof of your building. The gravel provides a significant amount of sunlight protection to the single-ply membranes underneath.

Ballasted roofs are usually installed new, but you can sometimes add ballast to an existing membrane roof. It adds a significant amount of weight to the roof, so you'll need to make sure that your building can handle the added weight of the gravel.

4. Switch to a Metal Roof

Finally, metal roofs aren't as affected by sunlight compared to other types of commercial roofs. The most significant effect is that ultraviolet light will cause the paint on the metal roof to fade. Using ultraviolet-resistant paint helps to minimize this problem.

Note that some areas that need sunlight protection also have high rainfall and humidity. Florida is an example. Metal roofs are extremely resistant to sunlight, but they often struggle with rain and humidity — they can begin to rust if the protective coating on the metal panels wears off. For arid climates, however, metal roofs are an excellent choice to maximize sunlight resistance.

Overall, the best method for most commercial buildings is to have a roof coating applied. It's best to have a commercial roofing contractor select your roof coating and apply it to the roof for you. If a roof coating would void your warranty, however, you can contact a service that provides commercial roofing in your area to discuss other options such as ballasting, roofing granules or switching to a metal roof.