field tested at lafayette general One characteristic of the spray adhesive that became immediately apparent during the Lafayette General project was its longer “open time”—the period within which the adhesive can create an effective bond with the flooring material—compared to traditional adhesives. This allows the installer to spread more adhesive at a time without worrying about it “dying”—losing its bonding ability.
Once sprayed on the substrate, the “open time” is two hours. Before applying the floor, the adhesive must dry until it feels “tacky” (15 to 20 minutes), with no transfer to your fingers when lightly touched. This minimum “tack time” increases in high humidity and low temperatures.
The main difference between the formulations for vinyl and rubber is the tackiness of the adhesive during the open time; rubber has different bonding characteristics, requiring a higher level of tack. The rubber formulation is also designed to dry differently.
The high lateral sheer strength of the spray adhesive keeps the tiles or sheets in place during installation, which means that the installer can work directly from the floor he’s just installed, pulling additional pieces toward him—which some installation experts say results in tighter seams and a faster pace. With a traditional adhesive, the installer is pushing pieces together while kneeling on the raw substrate.
One of the biggest differences in laying a floor with spray-on adhesives is that the flooring tiles or sheets are held firmly in place while the adhesive sets. Because traditional trowelled adhesives remain soft during the curing process, the flooring and the adhesive itself may move until the curing period is complete, from three days to a week.
Using spray adhesives allows the installer to release the floor immediately for the other trades or for initial maintenance. Workers can use the floor fully within hours, instead of days, and without fear of irreversible damage to the floor. This was always a punch-list issue, installers say; an electrician’s ladder, for instance, would leave permanent dimples in the floor by displacing the traditional adhesives.
getting installer buy-in “We were a little leery at first.”
Ben Lowery, vice president of operations at Cornerstone Commercial Flooring, says adopting the spray adhesive after a project was already in process wasn’t a complete leap of faith, having been impressed by the testing data. But still:
“We were walking into a job requiring 130,000 square feet of rubber tile. We weren’t going to be troweling at all, and had never used a spray adhesive. There’s a comfort level in trowelling, because a trowel is like an extension of a flooring contractor’s arm. To tell us that we’re going to go in and install that much rubber tile with an adhesive we hadn’t used before, and subject it to heavy traffic and heavy concentrated loads, definitely caused us a little apprehension,” he admits.
“But honestly, the real proving point was seeing for ourselves how well this spray adhesive worked, seeing it in action. The best thing about it is you can use the floor immediately after installation,” Lowery says.
“A large part of this job was floor by floor and everything was on a fast track. We would get done with a room and immediately there would be people installing beds, headboards, equipment and millwork literally within an hour of laying the floor. The hospital was right behind us every step of the way.”
In a project like Lafayette General, neither the interior designer nor the flooring contractor have any control over the schedule. In fact, they are often asked to find ways to make up for unforeseen schedule delays.
“Even when a schedule has been set, it’s being compressed every day,” says Lowery. “All the other trades are compressed, and we’re expected to go in there and save the day. Had we not had this new spray adhesive on this job, if we had to wait the usual 72 hours before allowing anyone on the floor, there’s no way the schedule could be kept. We would have had a very unhappy client.
“The time for actually laying down the floor isn’t that much different than with trowelling, because installers are pros,” he adds. “There also isn’t much difference in the adhesive cost per square foot, although the spray adhesive is a little lower in cost. The biggest consideration is immediate access to the floor. Removing the minimum three-day wait for curing is a huge benefit.”
Another time savings realized with spray adhesive, Lowery says, is the easy cleanup.
“You literally just have to wipe off any overspray with soap and water, which takes care of a lot of the flooring-related punch list items. Acrylic, epoxy and urethane are much harder to clean up. It never fails: the punch list will always say something about the flooring glue being on the walls. We have shields we hold up to catch splashes, but it always gets through. With the old adhesives, we had to use Goof Off or oils that leave a residue and a bad smell, and even paint thinner or mineral spirits. Sometimes it takes some pretty serious stuff to get those old glues off of floor surfaces or millwork.”