There are so many types of underlayment available to the retailer/installer these days that it is hard to keep track of them all. A quick history lesson is in order here to understand what and why we have OSB, OFB, Plywood-Birch, Plywood-Poplar, Meranti and Lauan/Mahogany. Which one is best for your customers needs? Vinyl manufactures have been saying it for years, “No Warranty if Lauan is used”. Why is this? Well, for starters these mahogany type panels where never intended to be used as underlayment; they started life as basement paneling back in the 1960s. Lauan is/was the generic name for the product originally manufactured in the Philippines. Then it shifted to Indonesia, then Malaysia in the ‘80s. Meranti is the generic name given for the Malaysian made product.

The next forest to be cut down for these type products is in…. China, and the generic product name is “Okoume.” The problem with these type products is, and will always be, lack of consistency. Discoloration and delaminating were all the rage back in the early ‘90s when perimeter glued products hit the market. That is why vinyl manufacturers dropped it off their recommended approved list! So what did we as an industry do to fix it? We made a big jump to prime time, going overboard (good pun here) to furniture grade plywoods. Russian and Arctic birch products are overkill for use as an underlayment. But the vinyl manufactures had to insure that their recommendations on underlayment would work with their warranties. Now the vinyl manufacturers state that any substrate issues are the sole responsibility of the underlayment producer.

Price is always a consideration when products are bought and sold, but who makes the decision for the consumer or end user with their underlayment? Meranti, Lauan and Okoume are commodity products, cheap and plentiful. I have talked to so many homeowners about this in years past that I assure you they would pay a little more if it kept their warranty intact!

OK, so we know a bit of the past now where are we going? With a little time and the Internet, it’s not difficult to see the trend. I am a slave to the computer like many of you. And with a never-ending thirst for knowledge, I have found that the underlayment answers we need may be closer than you think. Go due north into the land of the maple leaf and several questions will be answered. Did you know that the Canadian Government funded a study in the mid to late ‘90s to uncover the widespread problem of underlayment seam telegraphing? Nor did I!

I’m told that it is a two-inch thick novel with a very comprehensive study on the subject of underlayment seam telegraphing. I found over 30 causes for underlayment seam telegraphing at and the reading was very informative. So much so that I have to regress on a statement in an article I wrote 2005. Divergent staples are not recommended for underlayment fastening. I was wrong!! Divergent staples, as I now know, were designed for latticework. Who knew? Thermal coated chisel point only should be used for underlayment fastening! Also the thermal coated chisel point staples can protrude beyond the subfloor _ inch but not more. If the staples are not thermal coated (like hot melt) and is beyond the subfloor backing then the temperature difference from the top and bottom can form condensation on the staple and wick to the top (crown) and cause staining! Who knew this?

Here are some photos for thought. Photo 1 is residential vinyl in front of the refrigerator, a high-traffic area; what could be the cause here? The job was two months old at the time of the photo. The joint telegraphing-time line (borrowed from the Canadians) may be helpful. “You Make The Call.”

Photo 2

Photo 2 was taken within weeks of the installation. What could be the cause for this mole hole? “You Make The Call.”

In Photo 3, I have saved the best for last. I see underlayment seam; I see high joist seam; I see underlayment seam too close to high joist!! What do you see? “You Make the Call.”

Why reinvent the wheel, when you can learn from others and their efforts? Here is my last question: Should we always butt lightly and sand with or without patch? Thanks again for reading and have a great day!