Written By: Jacqueline LaDuke, National Technical Manager
The maple across the street is shifting from soft chartreuse to vivid vermilion. Though warm afternoons disguise it, earlier sunsets and crisp nights are quietly signaling winter’s approach. For those of us who relish frosty mornings, fresh snow, and the start of winter sports, autumn’s colors stir excitement for the season ahead. But for those of us in roofing, the beauty of fall often fades amid the rush to finish projects before cold temperatures, fleeting daylight hours, and weather delays set in.
In the north, most contractors will tell you that winter work can be tough– especially in the snow belt. When temperatures dip below 20°F and daylight disappears, production typically slows, welding can get more challenging, and keeping roofing adhesives warm can get complicated. Without heated stairwells or mechanical rooms for onsite storage, contractors often have to get creative to keep materials warm and ready for use. Maintaining proper material temperature is critical to a high-performing commercial roofing system.
As temperatures drop, cold-weather roofing presents unique challenges for contractors and designers alike, including adhesive performance, membrane flexibility, worker safety, and scheduling. Whether you’re wrapping up fall jobs or preparing for winter installations, these four essential tips will help ensure quality, safety, and efficiency on every project.
4 Essential Tips for Commercial Roofing Success This Winter:
1. Smart Materials Storage Starts Before Sunrise
Proper storage is key to successful cold-weather roofing. Most liquid and foam adhesives must be kept between 60°F - 80°F for at least 24 hours prior to installation. This ensures that the entire contents of the materials, from the inside out, are equally warm enough for use.
In the fall, it can be tempting to store adhesives or sealants outdoors when afternoons are still mild, but overnight temperatures can drop quickly and will ultimately lower the temperature of the product. Even if daytime highs exceed 60°F, nighttime lows near 40°F can cause materials to cool below their ideal range.
Using a product that hasn't been stored correctly can affect the overall performance and usability of the product as well as its performance within the commercial roofing system. This is especially true for materials that have more viscosity.
2. Avoiding Cold Weather Pitfalls During Roof Installation
Cold temperatures can impact nearly every phase of commercial roof installation. Membranes, whether it’s a modified membrane or single ply, need extra time to relax before installation. Sunny days can certainly help, but cold temperatures tend to keep materials stiff and harder to handle. Don’t forget, thicker and/or brightly colored, reflective membranes may take additional time to relax. The key thing to remember is the longer a membrane can relax in good conditions, the easier it will be to install properly.
Adhesives, liquid or foam, are critical elements in the performance of a roof system and can behave differently in cold environments. Depending on ambient conditions, these may have an “open time” (the usable window between opening and application) that is significantly reduced during the winter. Moreover, “flash off” or “tack time” (or the amount of time it takes for a material to reach tack) can be longer too, especially if the relative humidity is high and ambient temperatures fall below 40°F. Materials that froze overnight or that can freeze within 48 hours after installation should not be used (e.g, any water-based adhesives).
For hot asphalt applications, materials should be kept in insulated luggers prior to use. Moppings should be no more than 3 – 6 ft ahead of the roll during installation, and smaller mop heads should be used to minimize heat loss before bonding.
When heat welding membranes, whether by flame or by air, it can be super challenging during cold weather as well. Allow extra time for heating equipment to reach ideal temperatures for fusing materials. Multiple and frequent onsite TEST WELDS are highly encouraged to ensure that installed materials get a good, weatherproof seal.
Finally, pay attention to dew points, or frost points, in colder months. Moisture on the substrate, even in the form of frost, can compromise adhesion and performance, particularly for re-cover or retrofit installations.
3. Cold Weather Roof Maintenance: Safety and Performance Tips
Roof maintenance during cold months requires extra caution and planning when maintaining an existing roof during colder temperatures. Frozen single-ply membranes can be extremely slick, posing slipping and falling risks for maintenance crews.
It’s important to stick to treaded walkways or encourage building owners to install them so that year-round access can be easier and safer.
Cold temperatures can also affect the performance of cleaners, primers, adhesives, and heat welds. So, taking the additional time to dry or warm them before installation should occur.
4. Designing Commercial Roofing Systems for Cold Weather Conditions
While the timing of construction can often be out of the control of the designer, it is important to address it during cold-weather installation discussions. Environmental conditions and timing should always have a seat at the table during design considerations for roofing work. Installations when temperatures fall below 40°F can introduce unwelcome risk to projects and increase difficulty to contractors, depending on the types of systems that are specified. And as the risks and difficulties increase, higher installation costs are likely to follow.
While the fall season brings spectacular colors, cooler temperatures, and pumpkin spice coffee creamers, don’t forget that it’s time to dust off the old hot boxes, warming blankets, heavy jackets, and overalls, and gather extra propane for the burners. Working in cold weather isn’t easy, but with the right planning and materials, it’s entirely achievable.
About the Author
Jacqueline "Jackie" LaDuke, RRO, LEED AP BD&C, MCEM, MBA, is the National Technical Manager of Thermoplastics with Elevate, a commercial roofing systems brand, and a 25-year veteran of the commercial roofing industry. As a former contractor and consultant, she has extensive expertise in commercial roofing systems and is dedicated to ensuring roofing professionals have accurate, actionable information because Nobody Covers You Better. She holds master’s degrees in engineering and business and is an active industry member of IIBEC.