Adhesives Made of Polyurethane

Dallas New Construction Roofers - Commercial Roofers Dallas - CMAC Roofing (23)

According to industry surveys, two component polyurethane adhesives have the biggest market share in the commercial roofing sector when it comes to bonding insulation to roof decks. Because most threaded fasteners must be pre-drilled before installation many roof decks such as concrete and cement, can make fastening difficult. Because through-fastened systems frequently contain a large number of fasteners, the installed cost often exceeds the cost of the fasteners and stress plates. It’s also a noisy activity, as the holes are drilled using hammer drills. Two-component polyurethane adhesives can be applied directly to these more challenging deck types without the added complexity of fastened systems, and without the odor of other adhesive types such as asphalt.

These adhesives can be used to adhere insulating boards to each other, which is common in commercial buildings to increase insulation R-values. According to one study, mechanically attaching insulation to the deck and adding a second layer with staggered seams breaks the thermal bridge while also considerably reducing air migration. They’re also frequently used to adhere coverboards, which can aid improve hail resistance in some cases. Furthermore, some building owners prefer the look of an attached roof with no exposed bolts or plates.

Traditionally, the most frequent method of applying a two-component insulation adhesive has been extrusion. Contractors often employ a big caulk gun-style applicator or a huge low-pressure dispensing cart for these jobs. In a short period of time, compressed containers have also gained enormous appeal.

Two-part polyurethanes are often dispensed in liquid beads that spread out over many inches and rise 3⁄4 to 1 inch above the surface during extrusion. High pressure canisters usually dispense in foam, but they continue to react after they’ve been dispensed, so make sure to check the manufacturer’s installation instructions for when the glue is ready to receive the insulation or cover board. Depending on the adhesive formulation, a chemical cure occurs swiftly. Because the insulation is part of the roofing assembly, contractors should adhere to the adhesive spacing specifications of the membrane manufacturer.

The Part 1 and Part 2 components are mixed at the point of dispensing in these low-pressure extrusion systems, allowing the chemical reaction to take place on the substrate rather than within the tools or containers. Personal protective equipment (PPE) is often confined to eye protection and gloves because the adhesive is not atomized.

Due to their size and cost, high-pressure spray rigs have lost some appeal, but they are still a widely accepted and used method of applying two-part polyurethanes. These methods typically necessitate a lot more personal protective equipment, such as respirators and suits, but also allow for bulk packaging of adhesive components at a reduced cost to the end user.

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