Bamboo Flooring Problems & Types of Bamboo Flooring
Bamboo: Grass, Not Wood
Bamboo has risen dramatically in popularity for wood flooring for both aesthetic and environmental reasons. It can be regrown very quickly, provides a range of colors and looks, and grows in almost any climate. Bamboo is used in a wide variety of products from t-shirts to toys. There are over 1400 species growing worldwide, and most bamboo (the most common choice for wood floors) grows at astonishing rates and reaches maturity in a mere three years.
Bamboo has proven to be a versatile and functional floor choice for homes, offices and other facilities. However, understanding some basics of the construction process can help to make the right flooring choice from the start.
Bamboo flooring typically is constructed in one of three different forms: horizontal, vertical or strand-woven (ii). Horizontal and vertical bamboo floors are considered to be engineered products, providing the look of bamboo but significantly strengthening floors by laminating the bamboo to a stronger wood species as a sub-layer.
Strand-woven bamboo is considered to be a solid flooring product and is the strongest of the three types of flooring. It also contains lower proportions of potentially toxic adhesives. It is formed under intense pressure that makes it more resistant to moisture changes.
If properly harvested and manufactured, bamboo floors can be as durable and strong (or even stronger) than traditional hardwood floors. However, because of the variables, there are some specific moisture content (MC) precautions we recommend.
Special Moisture Precautions for Bamboo
If bamboo is the look you want, there are four things to consider in order to prevent moisture-related problems in your bamboo flooring:
- Moisture Meter Settings When installing the flooring, the source and the construction can influence the ideal moisture level for each environment, and the species setting or specific gravity (SG) can vary greatly depending on the manufacturer’s source and process. (It’s worth noting at this point that there is no standardized grading system for bamboo.) Companies like Wagner Meters are working with specific manufacturers to determine accurate settings, but because of the many different factors involved, make sure you check the manufacturer’s recommendation for your wood moisture meters SG settings or SG adjustment tables!
- Engineered or Strand Woven? If your flooring is an engineered product, it might be necessary to adjust the depth of your wood moisture meter readings to check both the top (bamboo) layer and the subfloor species. Both types of wood need to have reached a balance with the job site in order to prevent moisture-related flooring problems, and to not develop separation problems in the product itself.
- Environmental Controls (HVAC) Some recommend that those in regions with high humidity not use bamboo floors (i) due to the unpredictable rate of expansion and contraction during the seasonal changes. For installers in these areas, acclimation is crucial! After installation, it is important for homeowners in these areas to carefully monitor room conditions (temperature and relative humidity) to prevent potential problems.
- Acclimation The best way to avoid problems for any flooring product is to be sure that it has reached equilibrium moisture content, or EMC, with the space in which it will be installed. This is especially critical with bamboo. Unlike most wood floors, it can expand along its length, as well as its width, and strand-woven bamboo can take significantly longer than another flooring to acclimate. The room must be at service conditions, and sufficient time must be allowed to let the floorboards reach EMC before installation begins. Do complete checks with an accurate wood moisture meter, and don’t begin installation until the product has reached a stable MC level.
Types of Bamboo Flooring and the Challenges of Installing
Bamboo flooring and other bamboo products have been gaining momentum as an environmentally renewable resource for hardwood floors. There are several reasons why it has. Bamboo is not actually a wood, but a grass. As such, bamboo’s rapid growth and its ability to regrow from harvested roots make it very appealing to those who are conscious of forest depletion through excessive cutting. Its dense composition is also very appealing, as bamboo can withstand high traffic and remain strong and beautiful. For the flooring industry, bamboo has created a whole new set of factors to be aware of when using bamboo products.
The most important factor is that bamboo does not have a uniform density, and this can create problems when attempting to set a moisture meter to correctly read the moisture in bamboo. Bamboo flooring’s hardness (and its capacity to hold moisture) and density can vary significantly according to the species used, the growth region of that species, its maturity when harvested, the directional grain and the manufacturing process of the flooring.
Strand Woven Bamboo Flooring
Strand woven bamboo flooring – which fuses bamboo fibers together under high heat and pressure during the manufacturing process – is much harder than bamboo floorboards that run with the vertical or horizontal grain. And a horizontal grain is even softer than the vertical grain. If the bamboo flooring was manufactured from bamboo that was growing further up the stalk, the final flooring product might be weaker still. That’s quite a range of factors to consider.
Engineered Bamboo Flooring
Engineered bamboo flooring can be solid throughout, or can be a bamboo layer attached to a (typically) pine base. Bamboo flooring is comprised of many layers being glued together either vertically or horizontally to give a variety of looks and textures to the finished product. But if the layers used vary from each other, different moisture conditions can also exist within the same floorboard or bundle of boards.
Accurate moisture testing during acclimation and before installation is crucial. Because bamboo has a lower expansion rate than many hardwoods, it would seem ideal for any type of climate. However, at this point, grading criteria are not standardized for bamboo flooring and other bamboo products. So it pays to beware and be sure that your bamboo flooring is manufactured as carefully as possible.
While there is some suggestion that some commercial-grade finishes are stronger than job-site finishes, even the best finish can be ruined by excessive moisture. Testing the subfloor for moisture conditions is just as important as with any other wood floor.
In spite of what is being learned about bamboo products in the wood industry, as with wood flooring, it is clear that accurate moisture testing is still as crucial as ever. Even as dense as it can be, bamboo still is susceptible to warping, cracking and delamination if not installed and finished correctly.
It pays to be knowledgeable about the inherent strengths and weaknesses of bamboo and to research the manufacturers as thoroughly as possible. And then it pays to install it with the same care you would any hardwood floor.
Wagner Meters offers a variety of high-quality moisture meters for woodworking and wood flooring projects. Protect your bamboo flooring investment by accurate moisture testing your expensive flooring at installation.
Bamboo does offer both pros and cons as a flooring option for today’s homeowner and installer. However, it is necessary to take into consideration the specific qualities of bamboo flooring in order to avoid moisture-related problems.
Have bamboo flooring related questions? Read our top bamboo flooring moisture questions and answers.
Tony Morgan is a senior technician for Wagner Meters, where he serves on a team for product testing, development, and also customer service and training for moisture measurement products. Along with 19 years field experience for a number of electronics companies, Tony holds a B.A. in Management and his AAS in Electronics Technology.