Tom Parker, TCParker & Associates
The use of polyurethane roof tile adhesive continues to grow in the Florida market. As roofers, time and labor necessary to install a tile roof is greatly reduced compared to mechanically fastening. Homeowners are provided the security of fully adhered roofing assemblies, increasing peace of mind during wind events.
Mechanical fasters, typically screws today, have been the standard installation method for many years. This attachment method connects the head of the tile to the substrate. Adhesive assemblies attach the head of the tile to the substrate and some tiles lock at the overlap. This creates a more monolithic assembly which is significantly more resistant to failure in a wind event and reduces fastener penetrations.
Polyurethane adhesives are available in single component and two component versions. Both are based on similar polyurethane chemistry. Two component adhesives are mixed and chemically react at the point of application; single component adhesives are partially reacted at the factory and final cure takes place via moisture (water) in the air and on contact surfaces. Recently, hybrid
assemblies have been introduced that combine mechanical fastening to the deck with a bead of adhesive at the tile overlap.
As a roofer, there are advantages to both systems that should be considered. Large two component pressurized systems are available and can result in lower adhesive cost per tile (with medium paddy placement) and they typically provide the highest uplift numbers (with large paddy placement). Single component systems allow multiple applicators to work at once and can be applied on
wet substrates. One and two-component adhesives are available in self-contained packaging that will allow for multiple applicators at once independently.
Polyurethane adhesives can drive efficiencies for the tile installer. If you are utilizing full mortar set hip and ridge application, foam adhesives can greatly reduce the time necessary to affix hip and ridge tiles. Field tiles can be installed in a fraction of the time with adhesive versus mechanical fasteners with no chance of cracking tiles due to overtightening. In today’s world of labor shortages and
backlogs of roof jobs, efficiencies are key to a roofer’s ability to get more roofs down per week.
Each roof is a unique situation that deserves a design review. The FRSA-TRI Florida High Wind Concrete and Clay Tile Installation Manual, 5th Edition, is a great resource for determining the design requirements. The local authority having jurisdiction may also have preferences and requirements. By reviewing the actual requirements, both over and under designed assemblies can be avoided.
Under design can result in failures; over design results in needless expense for the homeowner.
Every tile manufacturer has performed uplift testing with specific amounts of adhesive applied to each tile in a specific pattern. The design calculations for a tile roof are based on the uplift results published in the Florida Product Approvals and Miami Dade Notice of Acceptance (NOA), therefore it is up to the installer to ensure the foam is applied properly.
Per Florida Product Approvals and Miami-Dade County NOA’s, each manufacturer includes product specific instructions with each
package and these should be read and understood by all installers. Successful installation and code compliance requires that product is prepared and applied per manufacturer’s instructions.
Begin with confirming that the products you choose have a Florida Product Approval via www.floridabuilding.org/pr/pr_app_srch.aspx. If the job is in Miami-Dade County, check for an NOA via www.miamidade.gov/building. The Florida Product Approval and Miami-Dade NOA number are listed on the package as well. Once confirmed, note that the products have a range of optimum temperature of storage and for application. Single component and two component kit products typically require shaking prior to use. Large two component pressurized systems require calibration prior
to and during application to keep the foam on ratio. Smaller, self-contained two component kits do not require additional equipment and provide ease of use. Consult manufacturers’ instruction manual for details.
Each foam manufacturer provides detailed written instructions along with drawings detailing the exact placement of the material (paddy or bead location) and the quantity of material (paddy or bead dimensions). These may be different for different tile profiles. It is imperative that the required amount of material is placed on each tile to ensure the design uplift numbers are achieved. In most cases, the manufacturer provides the square inches of contact area required and makes recommendations to pull up a certain number of tiles to check the contact area. Ensuring good contact area is always a prudent practice. The adhesives also have a specific “open time” or time until the foam “skins over” which must be observed to ensure adhesion. If the foam begins to cure before the tile is placed, it is unlikely to yield the designed uplift numbers. When in doubt, remove the foam and re-apply. For the
single component products, temperature and humidity have more of an impact as these are cured from moisture. The manufacturers provide a maximum time between application and placement of tile, typically 1 – 4 minutes. Also, recognize that there are specific bead/paddy sizes and placement for field tiles, eave tiles and hip and ridge tiles. In some cases, the amounts are dramatically
different for each of these locations, so be sure to consult the manufacturer’s specific instructions. Based on the roof pitch, fasteners may be needed in addition to the foam. Again, refer to the manufacturers’ instructions and the FRSA-TRI Installation Manual.
Finally, the manufacturer’s instructions and code bodies call out that each installer needs to be trained and certified by a qualified trainer and must carry a Qualified Applicator issued for the dispenser and product being utilized. All manufacturers provide this training, contact your manufacturer or local distributor who can help schedule certification sessions with a factory certified instructor.
Polyurethane foam tile adhesives are a great way to provide the homeowner the most secure roof system possible. Adhesive attachment also drives efficiencies for the roofer allowing more roofs per week to be installed. Given the history of weather events in Florida, it makes sense to have this offering available to your customers. Keep in mind that the manufacturers, FRSA and TRI’s expertise is also available to help you ensure successful installation.
Tom Parker is the owner of TCParker & Associates, a sales agency representing TILEBOND roof tile adhesive among other products. Tom grew up in the construction industry in his father’s residential construction company. He later earned a degree in chemical engineering and worked at Dow Chemical for 33 years prior to opening his agency in 2013. Tom is a Registered Professional Engineer.
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