Most composite shingles should be installed at temperatures between 40 degrees F and 85 degrees F, but manufacturer’s requirements may vary slightly. For reference, composite shingles can include any combination of two or more materials, such as fiberglass and asphalt.
According to Underwriters Laboratories, the best temperature to install asphalt shingles is between 40- and 85-degrees Fahrenheit. All composition shingles have self-adhesive sealant strips on the back side of the shingle that adheres itself to the shingle below. Sealing time will vary depending on the slope of the roof, its orientation, and the amount of sun and heat exposure that the shingle receives. The shingle adhesive will reach its ideal elasticity at 70 degrees Fahrenheit.
During installation, composite shingles must remain within the temperature range required by the manufacturer or the warranty may not apply. Most composite shingles are designed to be self sealing, a process very dependent on the ambient temperature of the air and the surface temperature of the roof.
Both extreme heat and cold can affect the durability and effectiveness of the entire roof, especially the shingles. Composite shingles installed below the recommended temperature range can result in shingles that are brittle and difficult to work with.
Composite shingles that are installed above the recommended temperature range tend to stick together, tear, and lose the granules so important to the durability of the shingle.
Interestingly, most homeowners are more concerned about extreme heat damaging their roof than extreme cold. However, shingles damaged by cold temperatures are more likely to cause the greater concern, which is a leak.
Cold shingles can break instead of bend, preventing the shingle from conforming to the roof. Cold shingles that fail to conform to the roof (and adjacent shingles) tend to create gaps between the shingles, which can allow water under the shingle.
If you are interested in learning more about the restrictions and logistics of roofing in winter, also check out the cold-weather-specific information at Can You Install a Roof in the Winter?
Here we will discuss the best temperature range for composite shingles and why careful consideration of the weather is so important to the installation of your roof system.
What Are Composite Shingles?
Composite shingles are layered, water-shedding surfaces made from at least two different complimentary materials. For example, a shingle made entirely of fiberglass strands would be durable, but not waterproof. A shingle made from asphalt only would be waterproof, but prone to impact damage.
The term composite shingles can include other forms of roofing like synthetic tiles, synthetic slate, and shingles. These composite materials are formed into shapes designed to mimic natural materials, like cedar shingles and natural slate. Fiberglass asphalt shingles are the most popular composite shingle material because the two materials complement each other in a way that is simple, cost effective, and durable. Other composite shingles (like fiber cement) do the same thing
Fiberglass asphalt shingles dominate the composite roofing industry, with the vast majority of manufacturers offering strip (also known as three-tab), dimensional, and luxury (also known as architectural) shingles. For more detail on the construction and components of composite asphalt shingles, see our main article about composite asphalt shingles.
Is It Ever Too Hot to Install Composite Shingles?
According to the US Department of Energy, the surface temperature of a typical roof with composite fiberglass asphalt shingles can reach 150 F. during summer. Most composite shingle manufacturers require the ambient temperature to fall between 40 degrees and 85 degrees.
According to the Occupational Health and Safety Administration (OSHA), weather reports should not be your only indicator that a roof is too hot for composite shingle installation.
OSHA notes that most weather condition reports are measured in the shade. Roofs in direct sunlight can raise the actual temperature of the roof by 13.5 degrees F, making the roof hotter than the air around it.
Weather reports also cannot account for other potential heat sources of a roof, like hot tar. Roofs tend to absorb heat, so any source of heat on the roof should be considered, not just direct sunlight.
Other composite shingles, like polymer and wood composites, are more resistant to deformation when very hot, but the recommended temperature should not exceed 90 degrees F. When the weather is very warm, humidity levels also tend to rise, except in arid regions.
Humidity has an adverse effect on the sealing of both self adhesive strips and roof adhesive, preventing bonding. Roof adhesive relies on both a dry surface and a minimum temperature (which is usually 40 degrees F) to prevent both wind lift and improper adhesion.
During Very Hot Weather Installation:
- Before installation, the shingles may stick together in the wrapper if stored improperly
- During installation, the shingles may be more easily damaged by foot traffic
- When temperatures are very high during installation there is a possibility that the shingles may tear during installation.
Can I Install Composite Shingles When It’s Cold?
Not all composite shingles are the same, as some are more resistant to temperature changes than others. The composition of synthetic slate for example, is both fire and moisture resistant by design. As a general guideline, temperatures need to be above 40F for installation. See our full article on winter roof installation.
Most of us in the U.S. live under a fiberglass asphalt shingle roof, which can be damaged by walking on them in excessive cold temperatures (20 degrees F or below). Even if the temperature is slightly above 40 degrees F, many pros will take extra steps to ensure the shingles seal to each other, or wait until temperatures are closer to 50-55 degrees and with the sun shining to install large areas of a roof.
During Cold Weather Installation:
- Before installation; store shingles in a heated area above 70 degrees for 24 hours.
- During installation, supplement the self-adhesive sealant strips by applying roof cement. The roofing cement should be administered onto four locations evenly spaced by one inch from the leading edge of the shingle and pressed in place. Many contractors (including Rhoden Roofing) avoid installing any shingles in temperatures that would require this step.
- When temperatures are very low during installation there is a possibility of “cold curling”.
Most shingle manufacturers recommend adding a thin bead of roof cement to the shingle if the weather is not predicted to warm up before rain or snow is expected. Generally, shingles will take a couple of warm days above 40 degree F to completely seal, but the rood will still shed water.
It is important to add adhesive sparingly, because eventually the self sealing strip will become warm enough to bond. If this happens, excessive adhesive can then get in the way of the adhesive on the shingle, preventing it from bonding to the shingle below.
Can Cold Composite Shingles Break If I Step On Them?
Composite shingles installed at temperatures below 40 degrees F can become brittle and struggle to conform to the roof decking. Three tab composite shingles fare a little better in cold weather than the more popular dimensional shingle because they are often thinner.
Dimensional shingles include randomly placed additional material on top of the shingle. The additional material adds dimension (hence the name) and texture to each shingle. Dimensional shingles are heavier and thicker than normal three tab shingles, which helps resist wind uplift.
Of particular concern are hip, valley, and ridge cap shingles as they often require a steeper bend. Many roofing pros store these shingles in the truck during cold weather to keep them warm until just before installation.
Is a Steep Roof Harder to Shingle In Winter?
Most roofing professionals are comfortable installing shingles on roofs with a pitch of 8:12 or less, but there are exceptions. For example, a flat roof will receive direct sunlight regardless of the time of year, at least in the continental U.S. Again, see our dedicated article specifically on winter roof installation
As a roof becomes more steep, a low winter sun may not rise high enough to melt any frost present. Even professionals can’t walk on an icy roof, so most use walk boards and other safety equipment to prevent accidents.
Roofing professionals use an array of safety gear, like special boots, harnesses, and toe boards to stay safe on a steep roof. Many professionals, including insurance adjusters, wear flat, rubber soled boots for better traction.
On very steep roofs, like 10:12 and 12:12, harnesses and toe boards are installed on the roof to help the installers maintain their footing. When frost is a factor, roofing installers are at particular risk, so the pros use every tool at their disposal to ensure everyone’s safety.
Are Other Roofing Materials Better Than Composite Shingles In Extreme Temperatures?
Generally a metal roof, known as a “5V” roof, will perform best in extreme temperatures. Five V roof panels do not rely on adhesion or curing to effectively shed water. These panels include a rib along both long sides that overlaps the adjacent panel, effectively shedding water away from the fasteners. Five V panels will move slightly with the temperature, but not enough to cause a leak.
Five V metal roofing relies on a rubber grommet attached to the fastener to prevent leaks instead of sealant. These fasteners (often #6 galvanized nails or self tapping screws) are located on each of the five elevated ribs, or “V”s formed into the panel.
This design prevents leaks because water cannot pool around a fastener and allow water under the panel. As such, fasteners should not be installed on the lower, flat area of a 5V roofing panel, as the grommet will eventually fail, leaving a perforation on the panel that can leak.
How Do I Avoid Accidents on a Hot or Cold Roof?
Many roofing accidents occur when the roof and shingles are either too cold, too hot, or wet. In fact, most shingle manufacturers warn against installing most roof materials (including composite shingles) when the roof is outside the recommended temperature range, or wet.
Dew, rain, snow, or frost can make a normally safe roof perilous to walk on, as well as allow materials to slide off. For this reason, most shingle manufacturers provide guidelines for composite shingle installation when the weather or condition of the roof is questionable.
Hot shingles can be damaged by simply walking on them, known in the roofing industry as “scuffing”. Shoes, debris, and hoses can dislodge the granules on the shingle, leading to discoloration and a point of failure.
Cold shingles that are installed outside the recommended temperature range are more likely to be lifted by wind because the sealing strip on the underside of the shingle is activated by heat. Known as “wind lift”, this event can apply so much force that the roofing tacks are literally pulled through the shingle.
Both situations should be avoided as both can create a dangerous environment for the installers as well as those on the ground.
When Is the Best Time of Day to Install Composite Shingles?
Most professional roofers are already working when the sun comes up. During the summer months, most professionals complete their work before the hottest part of the day. This makes handling the shingles easier and often prevents scuffing the shingles as the installers exit the roof.
In colder months, roofers can often work longer days. However, when the weather dips below 40 degrees F, roof installers must pause and wait for warmer temperatures. For this reason, most pros will only remove as much old roof as they can replace when the temperature is within range.
Conclusion on Temperature
Unless you have an emergency situation, wait until the temperature is at least around 50 to 55 degrees Fahrenheit with the sun shining to install your new roof. Night temperatures should be above freezing as well. On the most ideal day for installation, the sun will warm the self adhesive sealant strips and activate the adhesive, properly sealing the shingles. An experienced contractor will be willing to answer your questions and help guide you through your project. If you feel it is time for a new roof, call a professional for a roof assessment.
How Do I Find a Good Roofing Company?
Ideally, you’ll want to find a local roofing company with a stellar reputation and great customer service. If you’re new to the area, ask around on social media for a recommendation. You can also search online. Look for roofing companies that have won awards for quality.
Rhoden Roofing, for example, was awarded Master Elite Installer by GAF, one of the top five roofing manufacturers in the world. Roofing material manufacturers often award special status to roofing companies that exhibit stellar performance and represent their products well.
If you live in the Wichita, Kansas area, Rhoden Roofing provides expertise on roofing projects by offering free inspections.
Regardless of how you find your roofing contractor, the more you know, the better questions you can ask. The key is to find a contractor that understands the local climate and offers outstanding customer support. Roof installers like these will make sure your roof installation is a pleasant experience and provides you with decades of performance.
This article is part of our ‘How To’ Series. Learn more about:
- Installation of Roof Components
- Building Science & Roofing Systems
- Inspection & Hazards