Specifying Adhesives  for Flooring Projects

When working with an adhesive, remember to follow all of the manufacturer’s recommendations. If you choose to ignore any of the guidelines and the installation fails, fingers will most likely be pointing in your direction. (Photo courtesy of H.B. Fuller Construction Products.)

Flooring materials have no value until they’re installed and most flooring is installed with some type of separate adhesive, troweled or sprayed onto the substrate. Adhesives come in a variety of formulations for every type of flooring material and it is imperative the appropriate adhesive be used for the particular application. If you’re a fan of the old Andy Griffith show and fascinated with Barney Fife, one of my favorite lines he spews while indoctrinating new jailed detainees is, “The first rule is to obey all rules.” The same rule applies to installing flooring.

The most important rule to obey when it comes to installing flooring materials is to always use the adhesive specified by the manufacturer. Like it or not, what they specify for their product mustbe used regardless of your preference. Using a different adhesive other than what the manufacturer specifies will normally void any warranty they have on the product. This includes, believe it or not, defects in the product. Ludicrous as it sounds and while it’s not really enforceable legally, it’s an umbrella that covers the situation. It’s also an argument you don’t want to get into because it puts you in the middle of a very contentious situation.

The next rule to obey is the application of the adhesive. Make sure it is being applied with the correct trowel and that it has the correct open time, is rolled and follows anything else you are directed to comply with. Most often in failed installations that can be attributed to installation issues, you’ll find that the wrong trowel was used, preventing enough adhesive from being applied. You’ll also find that the adhesive had too much open time; that is, it dried too much so that “grab” was not properly achieved.

Adhesives now exist for high moisture and ph levels; however, you have to read each listed point of the coverage. Here’s some points listed in one manufacturer’s instructions that came up in a case recently: The limitations on the adhesive state it is good for up to 6 pounds of moisture vapor emission, ph of 9 and relative humidity levels of 78% at the time of installation.

The adhesive has a limited lifetime warranty, but to comply with the manufacturer’s warranty here’s what you have to do. 1) The substrate must be suitably prepared according to the manufacturer’s installation guidelines. 2) The adhesive must be properly applied according to those same guidelines. 3) Moisture testing must be done according to ASTM F-1869 or ASTM F-2170 for the bond warranty to be valid.

Additionally, the adhesive should not be used on slabs that do not have a vapor retardant membrane placed below the slab. This point negates all the other points. And in the case we have, there is no vapor retardant membrane. The installer would never know this unless someone does core drillings and that would likely occur after a failure. And, yes, in this case the installation has failed.

Alkalinity tests should also be performed. If the ph exceeds 9, providing you’ve done the test correctly and not breached the concrete surface layer too much or not enough, as this is a delicate balance, you have not complied. It is suggested the surface be washed with muriatic acid or vinegar and 10 parts water and rinsed twice. If this is done incorrectly it will also cause the installation to fail.

The points made exist here in some form for all manufacturers’ installation guidelines and adhesive applications. So you have to do exactly as they tell you to do. Even if you know that one adhesive is better than another, use what they tell you to use. Each adhesive has tiny colored “markers” that identify the adhesive, like its own DNA, so trying to “squeak one by” won’t work.

Not using the correct or specified adhesive, applying it incorrectly, not having the right conditions (which can include the substrate, environmental conditions or HVAC operation as well as any and all other compromising conditions) can create all kinds of problems. These can start with wrinkles to complete loss of adhesion and, of course, all of this will be attributed to your installation.

A point that must be made is that adhesive is not meant to hold curling flooring material flat to the floor. Modular flooring, soft or hard, should lay flat. Adhesive is supposed to keep it from moving around. If the flooring does lift on the edges, then that’s a product problem not an installation problem.

Check all modular flooring material before you install it to make sure it lays flat.  If it starts to curl after you’ve begun the installation, stop immediately and notify whoever is in charge. Take pictures, make notes and otherwise cover your behind so you can’t be blamed.  Don’t believe everything the label tells you; they allcome with an exception. So read everything before you start.  Assume nothing is the same because today, everything is changing.


Lew Migliore is president of LGMTCS and Associates in Dalton, GA. He is the author and publisher of “The Commercial Flooring Report” a monthly newsletter dealing with commercial flooring issues and information for commercial flooring contractors, manufacturers, designers, specifiers, and users of commercial flooring products. He is also the originator and instructor of the LGM Carpet Seminar, the industry’s only independent, objective, and impartial seminar on all aspects of carpet.