07 Jul Part II: Bamboo 2011-Style
Measuring moisture content in strand bamboo can puzzle even experienced hardwood flooring installers
Q: In Part I: Bamboo 2011-Style, you told consumers to consider their climate and the humidity of the environment before installing strand bamboo flooring. What you didn’t talk about is that the typical moisture meter a flooring contractor has on hand might not give him an accurate reading of the moisture content in the floor. This is needed when installing the floor, as well as later if any moisture problems arise.
When we needed accurate moisture readings a few years ago on a very large commercial installation, the strand bamboo manufacturer told us that we would have to send a piece of the floor to a laboratory for an oven-dry test. Sending pieces away and waiting for answers or trying to do a bake test in a home oven isn’t practical.
Is this a problem across the industry or an isolated incident?
— Flooring Contractor in Southwest, OH.
A: Your question is not isolated. The typical meter, particularly a pin-type meter, can give inaccurate readings because the resin content of the strand flooring interferes with electrical conductivity. But the strand bamboo manufacturer you dealt with should have been able to give you instructions on how to use a specific meter and get readings that were accurate enough to complete the tasks you had at hand.
An oven-dry test is the only way to get a completely accurate moisture-content reading – for hardwood and strand bamboo flooring alike — and contractors use meters to measure moisture content every day. Both types of flooring will cup (curl upward along the sides) if they come in contact with too much moisture, it is known across the industry that moisture levels in the flooring and subfloor should be measured before installation, and a strand bamboo manufacturer should be able to tell you how to do that in a practical way.
I have checked with two leading manufacturers. Both readily produced meter names and instructions that will yield a close-to-accurate reading. Style Limited, manufacturer of Bamboo Fusion strand bamboo flooring, has publicized this information to its distributors, including Natural Interiors® member Wanke Cascade, headquartered in Portland, OR.
“We have received questions from our dealers and their customers about this, and the answers have been readily available and spelled out,” Mark Buckwold, Wanke Cascade commercial sales manager, says.
When checking for correct moisture readings before installation, Style recommends the Klortner KT-50 surface meter, set on 5 – the setting for the highest density. This meter and setting will yield an accurate reading within plus or minus 1 percent, the company says. Standard Bamboo Fusion has a delivered moisture content of 6 to 10 percent.
If you are testing the flooring because of a suspected moisture problem after it is installed, Style recommends the Tramex PTM6005 pin meter. While the pin meter is less precise on moisture content in strand, it is more likely to help define moisture differences in different areas of each board, should such an issue arise, says Gregory Wilson, technical manager for Style Limited.
“Cupping is typically caused by imbalances in the product caused by moisture coming from the subfloor or environment and can be detected by testing different sections of the same board for differences in moisture content,” Wilson says.
Dan Smith, president of Smith & Fong which produces Plyboo bamboo flooring, says his company is comfortable in
recommending the Wagner MMC 220 surface meter and that Wagner has provided specific gravity numbers to set the meter on when testing Plyboo strand bamboo — .90 for Havana strand, .79 for Sahara strand and .86 for Plyboo’s Neopolitan strand. The delivered moisture content of Plyboo flooring is 6 to 9 percent.
Both companies offer detailed installation instructions, including how to acclimate the product before installation.
“It’s important to note that strand bamboo, due to its density and sometimes finished bottom, will acclimate more slowly than other bamboo or wood flooring products,” Smith says, which is why Smith & Fong does not finish the back sides of its flooring.
Plyboo produces flooring using both hot-press and cold-press methods, discussed in Part I: Bamboo 2011-Style. Moisture content, Smith says, is not affected by the method, but rather, by the proper curing, balancing and drying of the material.
“Hot and cold press can produce very different grains, textures and colors,” he says. “It is the art and the integrity of the manufacturer that gives each strand bamboo product its own unique look and performance qualities.”
Bamboo Fusion retailers include: Design Works in Spokane, WA; Major Brands Floor Supply in Seattle, WA; Interstate Flooring , Floor Factors, Floor Store, Eco Floors and Classique Floors in Portland, OR; Division 9 in Woodinville, WA (commercial work only); Contract Furnishings Mart in Redmond, WA