Wet set installation of resilient tile will fail if the adhesive open time is too long and there is no transfer of adhesive to the back of the tile.

Cork tiles in contact adhesive are set directly into place and tapped with a mallet for an instant bond.

As I was planning this month’s column, “Resilient Adhesive Update,” I found myself thinking that I’ve seen a lot of changes in adhesive technology since the early 1970s when we had nothing but solvent-based adhesives and the aromas they brought to the job. I remember the first water-based products in the 1980s and the evolution of our industry to the solvent-free, low-odor, low-VOC (Volatile Organic Compound) products we work with today.  Changes continue to happen with new adhesives and new flooring materials, so FCI editor John Moore asked me to do an update on the latest in resilient floor adhesives.

Originally developed for the carpet industry, the new technology in spray adhesives has come into more widespread use for resilient floors.

Spray Adhesives

Originally developed for the carpet industry, the new technology in spray adhesives has come into more wide use for resilient floors in the past several years.  I was on a job site this spring where spray was used to install solid vinyl tile (SVT) plank, and I was impressed with how easy it was to use.  I asked John Kozak, Technical & Installation Services Manager for Tarkett Commercial Tile and Larry Moore of SprayLock Industries about spray adhesives.  Kozak pointed out the advantages he has seen in the field since Tarkett introduced “Spray Smart” adhesive in 2008.   “The new adhesives offer superior moisture and alkali tolerance and eliminate special adhesive [such as two part epoxy] in areas of high static or dynamic loads because they eliminate indentations from adhesive displacement.” Moore added that “spray resilient adhesives use 80% less adhesive compared to trowel adhesive.”

“For the flooring contractor,” Kozak continued, “speed of application and less down time waiting for the adhesive to set, and no telegraphing of adhesive trowel notches are big advantages.   They can install more flooring in the same period of time, which means the end user can occupy the floor as soon as the installers have left since there is no tile shifting once the material is placed.” Moore agreed: “After flooring is rolled, the floor is immediately ready for all traffic including furniture such as hospital beds rather than having to wait 24-72 hours.”

There is also an advantage from an indoor air quality perspective, Moore explained, because typical spray adhesives are “rated 0.0 g/ml VOCs by EPA method 24,” making them a “zero VOC” product. VOCs are Volatile Organic Compounds and are a concern in occupied spaces and also on “green” projects. Numerous areas of the country now have strict rules for the use of any product so VOC emissions are key.  “Health care facilities are thrilled”, he explained, “since they can leave their HVAC (Heating, Ventilation, Air Conditioning) running while installing flooring with spray adhesives and immediately reoccupy patient rooms.”

 Installers have to adjust their work habits slightly to use spray adhesives. Making sure that the substrate is clean is key. Kozak explained, “Installers have to take a little extra time and added steps in cleaning the floor before spraying and  realize that their trowel is an adhesive metering device and not a broom.” His colorful illustration makes a very good point.  “It’s as simple as vacuuming or damp mopping the floor.  The most successful installers use a small auto scrubber as a last cleaning step and have found their call back punch lists have been eliminated, thus saving money and time in the end.” Moore added “Application is also much faster and done while standing up, not on your knees.” to which Kozak quipped, “I wish this product was available when troweling acres of adhesive with a scrap bucket behind me put me through college. I would have spent less time on my knees and they would be less creaky now!”

Application of spray adhesive is faster than trowel applied products and is done while standing up, not on your knees.

Cork Adhesive

One resilient product I have gotten to know well in the past 20 years or so is cork tile. Today it is more popular than ever in the United Stated and I have written about cork several times here in “Lets Talk Resilient.”  As an IICRC certified Inspector, I have seen a number of cork failures that were related to adhesive use so I caught up with Don Jewell, Technical Director for Capri Cork and asked for his feedback on cork adhesive. Before coming to Capri, he worked with Wakol, a large 70-year-old German adhesive manufacturer. Since Germany is the largest market for cork tile in the world, they have a lot of experience with cork, and “water based contact adhesives like Wakol D 3540 have been successfully used for more than 20 years,” he said.   Virtually every complaint I have seen on cork has been on floors installed with trowel applied adhesive, and Jewell explained: “Trowel on adhesives are popular because installers are most familiar with this type of application and have a greater comfort level.  When the directions are followed correctly it can be very effective and free of problems.  However, the margin for error is great - these adhesives tend to have very short open/working times and when these times are exceeded the strength of the adhesive bond is weak and the tile edges come up.” He went on to explain that the move to trowel adhesives seems to have reversed, as “quite a few manufacturers that “strayed” have come back to contact adhesive.” In fact, because of the very short open time with trowel applied adhesives, it is a “start and stop” process for installers.  Spread adhesive. Wait. Set tile. Roll the floor. Repeat.  Jewell confirmed what several installers have told me, “Installers experienced with contact adhesive often find it as fast or sometimes even faster than trowel on adhesives.” This is especially true because it’s possible to coat the tile a day ahead of time, so one installer can be prepping the floor while the other coats the tile.  The next day, clean the floor, coat the substrate, and lay the tile.  Some cork manufacturers are even offering “pre-coated” tile although there is concern about “shelf life” of pre coated tile so any older product may need to be coated on the back anyway.

The process for installing cork with contact is fairly simple, Jewell explained.  All you need is a knife, a paint roller and a rubber mallet. “Adhesive is applied on both the substrate and the back of the cork tile and then allowed to dry clear so you have several hours to set the tiles.  The cork tiles are then set directly into place and tapped with a mallet and it is this impact or contact that cause the two separate films to become one.”

 Jewell echoed what John Kozak said about a clean substrate. “Extra care must be taken to ensure a perfectly clean substrate as there is no trowel application to final “tack” the floor.  I must add that using the trowel and adhesive as a cleaning method is a very bad habit!”

"PVC Free" and Rubber Floors

One trend gaining some momentum in the resilient floor industry is the move to “PVC Free” flooring materials such as “bio based,” “polyolefin” and other products that look like vinyl flooring but do not contain vinyl or PVC at all. I caught up with Larry Press, Director of Flooring for Helmitin Adhesives for some insight on these materials.

“With regard to non-PVC materials, they are harder to bond and the adhesives previously relied on for PVC materials are inadequate,” Press said. “To satisfy products in the past, the manufacturers turned to either epoxies or polyurethanes, or in some cases provided a scrim or fiberglass backing to assist in adhesion. Our chemists have been able to overcome many of the problems faced with non PVC products which has allowed the use of acrylic adhesives, providing an “installer friendly” product meeting all regulatory issues and being classified solvent free.”

Rubber flooring, which has been around since before World War Two, is more popular than ever and presents some challenges that new adhesives are addressing. As recently as the late 1980s, about 80-85% of rubber flooring was installed with two-part “reactive” adhesive such as epoxy. “Wet set adhesives over porous applications has long been the standard, with neoprene contact, epoxies and poly urethane adhesives required for non porous applications,” Press explained. Adhesive technology, he continued, “continues to improve with development of new acrylic adhesives which allow for installation over porous and non porous substrates. There have been major inroads made on totally pressure sensitive adhesives that set harder than those traditionally used to tolerate the physical characteristics of rubber tile and sheet.”  This is good news for installers and people watching indoor air quality.  “With all the advances made to make the life of the installation professional easier and the necessity for “green adhesives”, he said, “there are advances being made every day with the environment and installation technique at the forefront while producing an adhesive that has been designed for it’s specific use.” 

Tape Systems

Another new development in adhesive technology in recent years are tape systems. This is a high strength heavy duty tape with adhesive on both sides that is rolled out on the floor.  After the floor covering is cut to fit, a paper on top of the tape is removed and exposes a tacky surface that the flooring is set into for an immediate bond.  This is not your home center type “double stick” tape, believe me.  This material really sticks!  There are two types available.

“Fiber re-enforced contact film” tapes are extremely strong and not removable. They are used for stair treads, stair nosings, carpet cove base and flash coving. These tapes are solid adhesive film throughout, with a cross-layered fiber to prevent adhesive from oozing out from the rolls. I first saw these in the late 1990s when used for resilient stair treads - a real time saver that allows for almost immediate use of the steps after installation.

Today, the technology has advanced even further as full surface acrylic textile reinforced dry adhesives are being used to install resilient flooring products. A thin woven fabric with adhesive on both sides is rolled out on the floor.  After the floor covering is cut to fit, a paper on top of the tape is removed and exposes a tacky surface that the flooring is set into for an immediate bond.  I spoke with Juergen Bahlo, President of Tek Stil Concepts, Inc., a major supplier of these products under the “Sigaway” brand.

“In Europe”, he explained, “full Surface textile re-enforced dry adhesives have been used for well over 15 years by commercial flooring  contractors and are adhesive manufacturer approved for the  installation of homogeneous and or vinyl cushioned back resilient flooring.”   There are numerous advantages over trowel applied adhesives, he continued, “Resilient products installed with Full Surface textile re-enforced dry acrylic adhesives experience no adhesive displacement under hospital beds or with forklift traffic,” so indentation from heavy point loads is not an issue.  Because it is a dry system, down time is eliminated as well, he continues: “There are great time savings because the floors can be immediately opened to foot traffic or heavy rolling loads as fork lifts and and heat welded products can be welded right away, without the usual overnight waiting time.”  These products roll onto the floor so there are fewer application errors, such as spread rate errors or open time errors, and there are no odors or VOCs. Another benefit is that full-surface textile re-enforced dry adhesives can be installed directly over non-porous concrete or structurally sound old floors, such as asbestos, terrazzo, tile, or failed poured urethane or epoxy, saving abatement and floor prep.

When using tape products, it is important that the substrate be perfectly clean.  The product can fail due to inadequate removal of dust from the substrate or failure to remove old floor finish wax when installing over existing resilient floors.  Like any other adhesive, Bahlo explained, “these products can fail because of ‘Installing when moisture content exceeds limits, installing over weak or dusty patch.”

Check with the manufacturer of the floor covering and the dry adhesive tape product to confirm which floor coverings can be used with this system.  For products that can, there are a lot of advantages in using this new technology.”

Installers Beware

Many of the failures I have been commissioned to report on are related to adhesive use - often the wrong adhesive for the job.  For example, you can’t put down solid vinyl tile with VCT adhesive!  Installers would do well to pay attention to the latest flooring and adhesive products. Don’t  assume that if a new type of floor or a new type of adhesive looks familiar that it is done the way you have done it before, and don’t believe the claims that are made about products unless the manufacturer can back it up.  Larry Press summed it up: “There are an astronomical amount of warranty claims flying about the industry with regard to just about everything other than it spreads itself, which may be the next claim to fame if this sentence is published! However, as the old saying goes, ‘if it sounds too good to be true, it probably is!’ Let the installation professional beware.”