Conquer the cold: Tips for winter spray foam application

By Dani Sheehan.

Discover how to tackle inclement weather challenges and achieve durable spray foam roofing with expert tips for cold-weather applications.

Spray foam roofing offers a versatile and durable solution for commercial roofing systems. While spray foam can generally be applied most of the year, there may be some climates where winter presents unique challenges. Optimize your cold weather spray foam applications by understanding how temperature and humidity affect these products.

Temperature and humidity recommendations

According to General Coatings Manufacturing Corp, applying spray foam is most successful in warm and dry conditions. If it’s actively raining or snowing, it’s best to delay the application. Foggy conditions should also be avoided due to the high moisture content in the air. In general, spray foam application should be done when:

• The relative humidity is around 50% or less

• The substrate temperature is at or above 50° Fahrenheit (F), and at least 5-10° above the dew point

• Rising temperatures and sunny skies during the day create more favorable conditions for application

Challenges and solutions for cold weather applications

Cold weather often increases the risk of trapping moisture between the foam and the substrate. This can lead to blistering, particularly under silicone coatings, or poor adhesion. If colder conditions cannot be avoided, using a winter-grade foam and applying a primer can help improve adhesion and performance. To mitigate these risks:

• Ensure substrates are sufficiently warm. General Coatings offers dark-colored primers with solar gain properties, which absorb sunlight to warm the roof deck and improve foam curing

• Use dark primers when temperatures are at or above 50° F

• Use preparation specific to the substrate type: Whether the substrate is plywood, metal or concrete the surface will need to be clean and dry.

• Select the proper materials to ensure proper adhesion to substrate type.

Timing and protection

Proper timing is crucial when working in colder climates. The goal is to have enough sunlight and heat to cure the base coat by the end of the workday. Always aim to apply a base coat on the same day as the foam application to protect the foam from UV exposure and ensure curing. In the winter, thinner acrylic base coats are typically necessary for proper curing as compared to summer applications, which may allow thicker application rates. For instance, if summer application rates involve one and a half gallon per square, winter applications might be as thin as ½ gallon per square depending on the conditions.

Leaving foam exposed can result in UV degradation, discoloration and reduced performance. Applying a thin base coat within the first several hours – or at minimum within 24 hours – helps protect the foam from these issues.

Winter application best practices

Planning is critical during the winter months. Additional time may be required to account for weather-related delays and adjustments. Consider these additional tips:

• Material and equipment storage: Ensure that spray foam materials and equipment are stored in temperature-controlled environments to maintain their performance.

• Adjust application settings: You may need to increase the spray temperature of the foam to improve its application in colder conditions.

• Scheduling flexibility: Build extra time into project schedules to accommodate potential weather-related disruptions.

• Production capacity: Shorter production windows on colder days will decrease the amount of squares that can be applied in one day.

Spray foam roofing remains a year-round solution, even in colder climates, when paired with strategic preparation and the right tools. By following manufacturer recommendations for temperature and humidity, starting with a primer and tailoring your approach to the various substrate types, you can navigate the challenges of winter application. The result? High-performance, durable roofs that withstand the elements.