Which is right for your roof; asphalt vs. adhesives? We’ve broken down the pros and cons of each so you can make the best decision for your commercial flat roof.
One of the oldest and perhaps the best method for bonding insulation within a flat built up roof assembly is by applying hot asphalt. For over 150 years, asphalt has been used to bond roofing layers together (including vapour retardant, insulation, cover board and membrane), creating a waterproof seal that protects all of the layers beneath it. Asphalt can be utilized as a traditional and versatile single component adhesive. Even though it’s one of the most common and trusted methods of insulation, newer adhesives are quickly becoming a popular alternative.
Asphalt equipment setup on the ground level
Pros of Asphalt vs. Adhesives
According to Roofing.net: Hot asphalt offers a single-source adhesive for bonding insulation to monolithic roof decks as well as for bonding multiple layers of certain types of insulation and rolled goods. Traditional asphalt is a reliable method of installation, and is compatible with a wide range of roofing materials. Traditional asphalt has:
1. Wide Substrate Compatibility
Asphalt is one of the most versatile materials when it comes to substrate material choices. When deciding on the adhesive method for your structure, the type of substrate that your contractor will be using will factor into their choice to use asphalt or not.
2. Multiple Product Application
Because Asphalt is a single component adhesive, it can be used for installation of multiple roofing products such as vapour retardant, insulation, and roof membranes.
3. Range of Temperature Application
Asphalt can be applied in hot or cold weather, which is an asset when combined with other membrane and insulation products especially in our Golden Horseshoe region of Ontario where temperatures fluctuate widely throughout the four seasons.
4. Lower Cost
Asphalt is a widely used roofing material with an easy application process, and for this reason is lower cost than some of the other adhesive options on the market.
Cons of Asphalt vs. Adhesives
1. Installation Odour
Asphalt has an unpleasant smell that lasts for the duration of the installation, and can last for several hours once the installation is complete. This is specifically important for structures that are within school areas or that house food production facilities. There are several workaround solutions available for this including Bitumar’s BURPack Zero low odour asphalt and other menthol additives that can be added to severely curtail smell issues.
2. Noisy Application
Asphalt installation can cause a disturbance to inhabitants of the commercial building under construction. If your repair or replacement requires noise control during office or school hours, your roofing contractor may suggest a different material.
3. Fire Concerns
Asphalt is installed using propane heat to maintain a proper application temperature. If fire is of concern within the structure (depending on use of premises – such as a textile factory) then additional considerations and/or alternatives might be required.
Pros of Adhesives:
Adhesives as an attachment method have seen a recent surge. According to Roofingcontractor.com, “environmental factors and building owners’ concerns with fumes have forced manufacturers to consider alternative attachment methods.” Adhesives have:
1. Less Complex Installation
Adhesives can usually be installed with minimal equipment and manpower simplifying the application process.
2. Wide Substrate Compatibility
Like asphalt, adhesives have a wide range of substrate compatibility. There are several kinds of adhesives (water-based and solvent-based) that work with almost all roofing materials.
Cons of Adhesives:
1. Sensitive To Temperature And Humidity
Some adhesives can be sensitive to temperature and ambient humidity (particularly dual components consisting of an activator). However, if your contractor is experienced with adhesives, they should be able to make the necessary adjustments based on temperature and humidity to ensure a smooth application.
2. High V.O.C
According to Asphaltroofing.org, “when in contact with sunlight, nitrogen oxides (NOx) and VOCs react together to produce ozone molecules.” National Ambient Air Quality standards only permit certain VOC levels, so your contractor must be mindful of that during the application.
3. Higher cost
The cost of adhesives is usually higher than asphalt.
Asphalt and adhesives are both reliable roofing materials that, when installed correctly, are both safe and reliable options for your flat conventional built up roof system. If you’re looking for more information on which materials would work best for your roof, or have general roofing questions, get in touch with us here. Our team of experts is here to help 24/7. That’s the Elite Advantage.