In this article, we share best practices for prepping bamboo, recommendations for adhesives and tips for measuring moisture in bamboo flooring.
Strand-woven bamboo flooring—which is made from strands of bamboo compressed into boards using extreme heat and pressure—is known for its strength, durability, and aesthetic similarity to hardwood. However, that is where all similarities end. Hardwood comes from trees; bamboo is a woody grass. The installation for each is not the same, especially in commercial environments.
Prepping the Bamboo
Jamann Stepp, director of marketing and product management, USFloors, said a key component to a successful installation is proper prep and planning. Bamboo should be acclimated for a minimum of 72 hours in the environment in which it will be installed, he stated. (Editor’s note: Seventy-two hours should definitely be treated as the minimum. We’ve heard from installers that strand-woven products can take weeks or in some cases even months to acclimate.)
“Ongoing room temperature should remain at 70°F, with relative humidity (RH) between 30%-50%. RH levels below 30% can and will cause movement in the flooring, leading to gapping, cupping and checking. Wood subfloors must have a moisture content of less than 11%. Concrete slabs must be tested for moisture content,” he said.
Stepp offered his opinion on the best type of bamboo flooring for commercial installs. “Due to its inherent hardness and dent resistance, strand-woven is the logical choice for commercial applications. Engineered strand in high-density fiberboard (HDF) or multi-ply, or solid strand is suitable.”
He recommended that all commercial applications be either glued or nailed down. “A 3/8” expansion space is required between flooring and all walls and any other permanent vertical obstructions such as pipes or cabinets,” he added.
Bamboo can expand along its length as well as its width, so care must be taken to ensure enough expansion space.
Larry Scott, vice president of field technical services, DriTac, shared his expertise on proper conditions for bamboo installation in commercial settings.
“The most ideal jobsite conditions when installing bamboo flooring include the utilization of an HVAC system. The use of an HVAC system will help control the environment and stabilize moisture levels at the jobsite,” he said.
The HVAC system should run for a minimum of 72 hours prior to installation and be maintained at ‘live-in’ conditions at all times once the installation has been completed. It’s not possible to properly acclimate the flooring unless the space is constantly kept at these ‘live-in’ conditions, he stressed.
Scott swears by the company’s Supreme Green, DriTac 7800—a multifunctional flooring adhesive for hardwood and bamboo flooring installations in both commercial and residential environments.
“Choosing a premium-grade adhesive suitable for installing any particular flooring type will always be of the utmost importance,” he stated. “Employing an adhesive that does not contain water is important and will assist in attaining advantageous results when installing bamboo flooring.”
Jeff Johnson, business marketing manager of Floor Covering Installation Systems, MAPEI, noted bamboo flooring can be installed using MAPEI’s Ultrabond ECO 995 and Ultrabond ECO 985.
“Typically, a commercial project means the subfloor is going to be concrete. In that case, the most important aspect of the installation is to make sure the concrete is dry enough to accept bamboo. Bamboo is very sensitive to changes in moisture or humidity so it is important to test the concrete slab for residual moisture. The results of those tests will drive the decision as to which installation system will be necessary for the conditions at hand,” said Johnson.
He said that, in general, the best installation method for bamboo is one that provides a moisture barrier as part of the product offering. Otherwise, it would be highly recommended to install an epoxy-based moisture vapor barrier system first before proceeding with the bamboo installation.
“Bamboo provides some incredible visuals and a great environmental story for a commercial environment, but it is still a natural product and as such is more susceptible to damage in a high-traffic environment,” Johnson added. “Care should be taken to provide walk-off mats in appropriate locations to remove debris from foot traffic, and rolling equipment should be set up with wide-format wheels to dissipate point load conditions.”
Bob Behnke, technical service manager of Titebond products for Franklin International, and Mark Lamanno, Franklin’s technical market manager of flooring, both recommend their one-step adhesive, moisture and control systems for installing bamboo flooring. These products (Titebond 771-Step Adhesive, Moisture and Sound Control and Titebond 821-Step Adhesive, Moisture and Sound Control) offer one-coat application and give the installer unlimited moisture protection without performing calcium chloride or in-situ RH testing, they noted.
“A successful installation requires a static temperature and moisture-controlled environment, with the bamboo acclimated to that environment. The HVAC system must be operational and remain static for the acclimation period and life of the floor,” stated Lamanno.
Behnke stressed how critical it is for the subfloor to remain dry. “Moisture is the nemesis of flooring, including bamboo. By keeping the moisture in the subfloor in check, the floor will experience less movement and less stress on the glue holding it down. The larger the floor (and commercial spaces tend to be larger than residential), the more total movement the adhesive will see, especially at the edges, so installers want to use a flexible adhesive for these larger sections.”
Ron Loffredo, area technical manager, TEC, echoed these sentiments: “You need to have an acclimated, controlled environment in which the HVAC is working. Subfloor conditions need to be smooth and level.”
He said TEC WoodPerfect Advanced Performance Wood Flooring Adhesive maximizes performance with installer-friendly benefits. “Unlike premium urethanes, WoodPerfect delivers one-step moisture control, strong initial grab, sound deadening and crack bridging capabilities in an installer-friendly, lightweight formula that’s easy to apply and easy to clean.”
“Moisture is the nemesis of flooring, including bamboo. By keeping the moisture in the subfloor in check, the floor will experience less movement and less stress on the glue holding it down.”
A best practice is to coordinate with the project manager to ensure that the adhesive cures overnight before opening the flooring to other trades with high traffic and rolling loads, added Loffredo.
Measuring Moisture Content
Grete Heimerdinger, vice president, Lignomat, explained that generally speaking, suitable moisture conditions for wood floors are also suitable moisture conditions for bamboo floors.
“The challenge to measure moisture in bamboo is that bamboo is not made from wood, but is a grass,” said Heimerdinger. “In addition, bamboo floors—especially strand-woven bamboo—contain a lot of glue and other chemicals. Lignomat’s pinless meters for bamboo—including strand-woven bamboo—are the Ligno-Scanner SDM, the Ligno-DuoTec BW and the Ligno-VersaTec.”
She said the measuring depth of all Lignomat pinless meters for bamboo is set to 1/4”. While the standard measuring depth for pinless meters is 3/4”, that is too deep for bamboo floors since they are usually produced at a thickness of 5/8” or less, she said.
“Lignomat’s pinless meters use bamboo-specific calibration settings, which are different from wood settings. The Lignomat bamboo calibration settings give a wood moisture-equivalent percent value, which makes it easy for floor installers working with both wood and bamboo,” said Heimerdinger.
Andrew Rynhart, managing director, Tramex, stressed the best jobsite conditions are when the in situ RH test readings and moisture content (impedance) readings are both low, and the environmental relative humidity and temperature are at the same levels as when the floor will be used. These ideal environmental conditions are usually between 45% and 65% RH and 65° and 75°F.
“A very good way of identifying the correct moisture level in bamboo flooring is to keep a small sample of the product in a place with stable ambient conditions, such as in an office or at home. This will allow the installer to compare the moisture values of this sample with the results of those taken from the jobsite,” he said.
Jason Spangler, flooring division manager, Wagner Meters, said the company’s best-selling meter for wood flooring and woodworking applications is the MMC220 Wood Moisture Meter—ideal for measuring moisture content in all wood species from rare tropical species to the more common softwoods and hardwoods, as well as bamboo.
“The environmental and jobsite conditions should be as close to occupied conditions as possible,” he noted. “Proper subfloor conditions are dependent on what type of subfloor is being installed upon (wood or concrete) and/or the installation process being used (floating, glue down, nail down).”
With strand-woven bamboo, variations in the manufacturing process can include the type/age of the bamboo used and inconsistent drying during the manufacturing process, Spangler stated. “Glues are also being used to bond the strands together, so this adds another tricky element to measuring moisture. Make sure to check with the meter manufacturer you are using to ensure you have the most current setting for the product you are measuring.”
He said that, due to the inconsistencies in the density and manufacturing of the product, forecasting acclimation time is difficult. “Many people will say weeks, not days. One thing is for sure, you need to fully understand what your acclimation MC% (moisture content) target is, so you have comparative information when measuring the strand-woven over time with your meter. Ensure you have correct and consistent ambient conditions (RH% and temperature) during the acclimation process, and then use that information to calculate Equilibrium Moisture Content (EMC). That will give you the target MC%.