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Floor Finish Adhesion Failure is a Profit Taker

You, the retailer/contractor, have just installed and finished (or recoated) a beautiful hardwood floor. The owner is pleased, which means that the final installation transaction - your final payment is about to take place. It's "Money Time."

But if the finishing process doesn't go well, Money Time won't arrive as expected. Worse yet, if you find out after Money Time has come and gone that the finishing process didn't go as planned, then a callback ensues and the cash flows the wrong way - back out of your pocket.

As a retailer/contractor, you can provide the future floor owner with a perfect subfloor, and a flawless installation and sanding job. But if anything goes wrong with application of the floor finish, you will not be paid. Ironically, your profitability in most instances relies on the portion of the job - finish application - that requires the least amount of material and labor from you.

But let's get back to the hypothetical job I cited at the outset of this article. Everything went well - or so everyone believes. You receive final payment, tell the homeowners how to maintain their new hardwood floor, and then you move on to your next job.

Several weeks later, however, you receive a phone call from what is now a rather unhappy customer. Although he tries to explain the problem to you over the phone, you decide it's best to go to his home and take a look for yourself. Upon inspection of the floor, you determine that you're looking at adhesion failure.

Now it's time to play detective. What went wrong, and when, to cause the adhesion failure? Generally speaking, a wood floor coating will exhibit poor adhesion for one or more of the following reasons: product failure, insufficient surface preparation and/or contamination. By carefully considering all three variables, you can usually diagnose the reason for the adhesion loss. Or even better - by understanding the causes, you can avoid their effects.

Finish is supposed to stick. The one applied to our hypothetical floor didn't and, therefore, the product failed. Product Failure is the most obvious but least likely reason for adhesion failure. If a product had a fundamental formula problem that caused adhesion failure, then it would also exhibit other problems and you would be experiencing the same type of failure on all of your other jobs. Similarly, finish manufacturers would be fielding claims throughout the marketplace as the job failures mounted due to the faulty batch of product. Product failure, while rare, is almost preferred by finish manufacturers because they can easily assist you in making your customer happy and move forward.

Surface Preparation has changed drastically over the last few years. The simple screen and recoat has become more complex. Today, there are many ways to abrade a floor. In some cases, certain finishes do not require abrasion for adhesion provided specific conditions are met.

When abrading a floor, you can use screens, pads, strips, or combinations of all three. The important thing to remember is: if the finish you are using recommends abrasion, you should do so AND do it thoroughly.

Over the years, I've been asked many times what I recommend for proper abrasion. I don't like to answer a question with a question, but in this case I have two. First, do the abrasives you use give a good, even powdering and/or properly smooth the surface consistent with the coating technology you are using? And second, are your finishing jobs consistently showing good adhesion? (It's important to keep in mind that contractors and finish manufacturers can learn from each other.)

If your answer to these questions is "yes," and I don't hear you mention any alarming details, then I wouldn't recommend any change in what you are doing. Any and all questions about proper surface preparation should be directed to them Manufacturer. Finish failures hurt everyone. On the other hand, we all profit when we can avoid them.

Contamination is the third and possibly, most common reason for adhesion failure. The sources of contamination are limitless. Many sources originate in the environment and are nearly impossible to identify. Others result from improper finishing procedures. Below are some of the most common sources of contamination:

  • Other trades working on the wood floor job site.
  • Mixing coating technologies and/or formulas.
  • Your applicator (even though you think it's clean).
  • Old coatings on existing floors (with no known history of maintenance procedures).
  • Maintenance product residues (cleaners, waxes, over spray from furniture dusting aids).
  • Make-ready clean-up crews.
  • Finish undercoats (previously applied stain, sealer or finish).

All of these may seem to be obvious sources of contamination except, perhaps, the last one. In fact, if the previously applied coatings were not properly applied or cured, they can behave like a contaminant. This is true whether they are the same product, similar products or products designed to work together. A common illustration of what I'm describing is when a stained floor reacts at the side joints with its urethane topcoat.

To help you with your next floor inspection, keep in mind the following points:

  1. Adhesion failure occurs from the bottom up, not from the top down. The coat that is peeling is usually the symptom. The cause lies below the peel level.
  2. Don't skip or skimp on abrasion steps, and don't push recoat times. These are recommended for a reason.
  3. If adhesion failure is localized, the floor is pointing you toward the problem. If you have side joint adhesion problems and not on the face of the board, what makes the affected area different?
  4. If adhesion failure is not localized - but widespread instead - it will probably peel over the entire area.
  5. Poor adhesion- is exacerbated by foot traffic. Traffic areas will show the failure first, but the remainder of the floor will fail also -just at a slower rate.

I hope this information will help you understand and, hopefully, avoid adhesion failures. Unfortunately, if you're in this business long enough, it's really a matter of when the adhesion failure nightmare occurs, not if it occurs.

Source: National Floor Trend Magazine - July 2000