While roof coatings are typically part of any roof replacement, each product reacts differently to cold weather. This is especially true for acrylic coatings, which are essentially based on water. Without proper storage or application, such products are likely to dry improperly or even freeze if temperatures drop low enough the night following their installation!
On the other hand, solvent-based coatings, such as urethane and silicone, won’t face the same problems as water-based coatings, but they still have their drawbacks. When stored in colder temperatures, these roof coatings both thicken to the point that they can’t be sprayed or rolled properly.
Although roof coatings can be a bit difficult to work with during the winter season, knowing the proper ways of application can help you save time and money without sacrificing performance. Here’s what you need to know.
Tips on Properly Applying Roof Coatings
If you want your roof coating to be applied successfully, make sure to follow these important guidelines:
- Keep the product as close to room temperature as possible. If you’re planning to keep it outside, make sure to store them close together under a tarp so that it will slow down the internal temperature drop. Doing this will keep the viscosity and application properties closer to standard for longer, especially when using asphalt-saturated roofing felts in cold weather. Otherwise, they’ll become brittle and crack at temperatures lower than 40 degrees! Fortunately, unsaturated membranes like polyester aren’t affected by cold temperatures, though they still must be kept dry.
- Heating shouldn’t be necessary if you already have proper storage. On a jobsite, contractors may have several means to keep roof coatings at warm or room temperatures, including heated storage units for heavier-bodied coatings or warming devices that use circulating oil. This is needed for easier spray application as well. If you’re not sure, make sure to consult with your trusted roof replacement contractor on what type of heating equipment should be used.
- When preparing for application, the surface must be clear of frost, snow and ice. Afterwards, follow the manufacturer’s standard application directions. Unless specially formulated wet-surface products are used, the surface must be dry for solvent-based coating products.
- When applying the roof coating, we recommend waiting until the afternoon on a sunny day to do it so the roof gets warmed up as much as possible. Certain coatings, such as emulsified-asphalt aluminums, might require special care, so be sure your hired roofing and remodeling contractor is aware of this.
If the surface of your roof is black, it will absorb more heat and make the roof temperature warmer than the air temperature. This usually improves the overall cure rate.
- Always expect the cure time to be longer than when applied on a warm summer day, even with modern technology allowing the application of roof coatings at low temperatures. For instance, a product that might cure overnight at a temperature of 70 to 75 degrees will likely take several days to cure at 40 degrees. Emulsion-type coatings even require temperature conditions that permit thorough water evaporation before being subjected to rainfall or freezing or standing water. If possible, consider using a polymer-modified emulsion in cooler temperatures so you can benefit from having shorter set and cure times.
Which Roof Coating Should You Get for Cold Weather?
Keep in mind that it’s not recommended to install any roof coatings, whether water-based or solvent-based, in below-freezing temperatures as precipitation on the roof will not be as evident. Water-based coatings should only be installed at 50 degrees and rising to avoid all of these types of issues. For a solvent-based coating, make sure it’s stored at 70 degrees so it will successfully spray or roll on a roof even with a surface temperature of 35 degrees to 40 degrees.
Below are the cold weather applications for each of the coatings found in most roofs:
- Silicones and urethanes – There are some roofing systems that have silicone and urethane coatings. Both are solvent-based coatings, so they can handle colder temperatures during the drying process. However, urethane and silicone roof coatings are prone to thickening inside the pail if not stored properly, so they should be stored in temperatures of at least 70 degrees.
If the coatings are being stored on a jobsite, ask your roofing contractors on how they’re being kept. They should at least be in an enclosed trailer with portable heat, or, if they’re being stored on a rooftop, they should be covered with a black tarp so the dark color will help absorb the sun’s heat and keep moisture off of the pails.
If a silicone coating becomes too thick, it can be thinned using 100% pure mineral spirits or xylene – so long as the thinning process does not exceed 5% of the solvent, and a thorough mixture has been ensured. Meanwhile, urethane is a mastic, so it’s designed to be thick. But if it becomes too thick to use, it may not be possible to thin.
- Acrylics – As we mentioned earlier, acrylics that are water-based are prone to improper drying or freezing if left in low temperatures for an extended period of time. They’re no longer usable once frozen, even after thawing. As such, temperature should always be taken into account for storage of such roof coatings.
Let’s say that the warehouse in which the products are temporarily stored gets cooler than 30 degrees. If this happens, the coatings should be moved to a heated area. During application, your hired applicator should also ensure that the temperature is 50 degrees and rising to prevent slowing of acrylic dry time. It’s also important to remember that acrylic coatings are also affected by warmer temperatures. Dew and humidity, in particular, can make a big impact at the dry time of acrylic coatings.
Whether you need to install solar roofing or apply a roof coating to your home property, our team of certified contractors can get the job done professionally. Call Bay Valley Contractors today at (925) 705-7889, or you can conveniently reach us online!