When I started in the industry in the 1970s, the most common underlayment was hardboard underlayment such as Masonite™ and other brands. By the early 1980s, the industry moved away from hardboard because of major problems with joint telegraphing, and lauan started getting used a lot. Back then I was a flooring retailer and we sold a lot of fully adhered sheet vinyl over wood subfloor systems that had old floors down. Rather then tear up old floors, we installed a lot of underlayment and I don’t recall many, if any problems with lauan back then. However, as time went on, we started to see problems with voids and joint telegraphing that forced us to have some serious conversations with our supplier to be sure we got the best quality lauan available. For example, the so-called 1/4-inch lauan we were buying came in two different thicknesses – 5.1 mm and 5.3 mm, neither one of which is a full 1/4-inch, but since we were trying to smooth out substrates, we felt the thicker product was better. However, lauan then and today never had more of a warranty that just on the product itself, so if a floor failed we might get a credit for some new boards, but not much else.
I did a research project for one of my clients two years ago and I was able to find over 20 references against using lauan as a flooring underlayment, from flooring manufacturers and a variety of other sources.
The Import Plywood Marketing Group, Inc website says, “Lauan or Meranti was never intended to be used as an underlayment for vinyl flooring. It was originally designed as a three-ply plywood for paneling.” The National Association of Home Builders said “Typically, 1/4-inch luan plywood is used as an underlayment when vinyl is installed over wood subflooring. The problem with luan is that it is soft and susceptible to denting and crushing under concentrated loads such as furniture legs or high heels. Flooring manufactures agree, and Tarkett said, “A wide variety of species and grades of Lauan plywood have been imported into the United States and sold for use as underlayment. Many of these panels have caused severe problems such as discoloration, delamination and adhesion failures.” Many other resilient manufacturers have similar statements, so if you are using lauan, the word warranty may not be in the conversation.
I spoke with Mark Violand, a full time floor covering inspector and, with me, an active member of the IICRC (The Institute of Inspection, Cleaning and Restoration Certification) inspector training and certification committee. Mark reminded me of a great column by Bill Baxley right here inFCI(“One More Reason Why Not Lauan by Bill Baxley,”FCIMarch 2004). In that column, Mark and Bill told an interesting story about a failure related to lauan. A residential vinyl job where an existing vinyl was covered with lauan underlayment prior to the installation of a new paper/felt/mineral backed vinyl floor covering.
Reggie Hill of Floor Covering services and consultants has seen lauan as an installer, a dealer, a manufacturer’s technical specialist and as one of the most respected consultants in the resilient industry. He told us he “would not even consider luan for residential or commercial since it is inconsistent in quality, performance and often has staining and discoloration issues from underneath the vinyl.”
Wally Ruttgheizer, CEO of Parterre Flooring Systems, has been involved in the commercial resilient industry for decades and said, “Lauan was, at one time, a pretty good underlayment but as the quality went down and other plywood underlayments were specifically developed and warranted for use under resilient, it became obsolete.” Unfortunately, the word has not gotten out so lauan is still used on a lot of jobs. “The home centers, lumber yards and even some flooring supply houses,” Ruttgheizer added, “continue to sell lauan for underlayment even though there are alternatives that are superior, especially for commercial environments where the floor are subject to a lot of stress and need to be installed over a solid, stable substrate!”
There are dozens of references that warn against lauan. The good news is that there are other panel underlayments are available that are much higher quality. I prefer “real” plywood that is comprised of layers of wood throughout, so there are no voids. My favorite is what is known as “five-ply arctic birch,” also known as “Baltic or Russian birch.” This is sold under a number of brand names today, and is readily available. There are also some other plywood panels such as the Canadian “Multiply” brand that are made from hard woods and are of excellent quality. These products perform well and have a manufacturer’s warranty, which you will rarely see in lauan. You can also use standard “A/C” grade plywood from the lumberyard, but chances are there is no warranty on this type of panel like there are for the other products I have mentioned.
Some of the products I have mentioned cost more than cheaper underlayments like lauan, but most customers will pay more for a better product with a manufacturer’s warranty, so why take a chance?