Common Causes of Bamboo Flooring Shrinkage

Bamboo Flooring ShrinkageMore and more homeowners are considering bamboo flooring for their homes because of their rapid renewability, toughness, and affordability.

When it comes to shrinkage there’s a lot of misinformation (and confusion) on the internet, and a wide range of experiences had by different homeowners across the globe.   In this article we will provide you with accurate information about how to choose, install and maintain bamboo floors that will give you trouble-free use for years to come.

As with any other durable good you purchase, do your homework!  Start in the right direction by investing about 30 minutes of your time into researching the bamboo flooring brands/companies you’re considering by looking for reviews and complaints on the internet.  There are lots of high quality bamboo flooring options that are also affordable (think $3-$5/square foot) if you find a company that specializes in bamboo; these prices stack up very favorably against traditional wood floors.  Some brands are known for shrinkage, so be on the lookout.

From then on it’s all about choosing the right type of bamboo flooring, and installing and maintaining it correctly.  If you choose the right brand, and the floor is installed and maintained correctly, you will be rewarded with a beautiful, stable, and extremely long-lasting and eco-friendly floor!  And don’t forget, always make sure your installer reads the installation instructions prior to beginning.

Below are some common reasons why homeowners have expansion and contraction problems with their bamboo floors (and all wood floors) in general.

 

Not Acclimating The Floor Properly

It’s very important that all wood and bamboo floors acclimate prior to installation. High quality bamboo brands can be acclimated in as little as 72 hours, whereas lesser quality brands may require a couple of weeks to acclimate.   It’s generally recommended that you allot for additional days when acclimating in a very high or low humidity geographical location.  Finally, always read the manufacturer’s directions about the how/what/when and where of acclimation.

 

Choosing The Wrong Brand

When bamboo flooring is manufactured there is a drying and moisture balancing period (before milling) that is crucial to the dimensional stability of the flooring.  Unfortunately some companies rush their products to market, failing to dry the flooring for the requisite period.  This results in “wet” bamboo floors, which over time will lose their moisture and begin to shrink (especially in the winter time).  The floors that are most likely to experience this problem are solid (as opposed to engineered) click lock floating bamboo floors.  These problem floors have often either been improperly moisture-balanced, or sold under misleading circumstances, as some retailers do a poor job of informing their customers up front about the maximum run limits (see below) regarding solid floating floors, as it may inhibit the final sale.  Many homeowners experience problems much later, only to be told that the run limit requirements were buried in their installation instructions.  As with any other large purchase you make, it’s always smart to search for reviews or complaints on the web about the brands you’re considering, from real review sites or online message boards.

Exceeding The Maximum Recommended Runs

If you’re nailing or gluing down your floor, live in a climate that has stable humidity year-round, or have a built-in humidity control system that will keep your interior humidity within a 30% range year-around, the maximum run limitations outlined below may not apply to you.

In environments where the humidity varies more than 30% in any given year, solid floating bamboo floors have limits to the successive “runs” they can be laid in.   A “run” refers to the maximum continuous distance your floor can be laid before you have to stop the floor, install a molding (most often a t-mold), and then continue the floor on the other side of the molding or break point.  These break points minimize the contraction effects from multiplying over long distances that result in separation from walls and gapping.

  • Tongue and groove bamboo flooring, when nailed down or glued down, has no run limit – your “runs” can go on forever. (better than it sounds ;o)
  • Engineered click lock bamboo flooring requires break points at 25 feet across the widths of the planks and at 40-45 feet down the lengths of the planks.
  • Solid click lock bamboo flooring requires break points at 15 feet across the widths of the planks and at 20-30 feet down the lengths of the planks.

Generally speaking, long runs of flooring should be glued or nailed down.

 

SOLID CLICK-LOCK BAMBOO FLOOR (is “floated”)

Solid Click Lock Bamboo Floating Floor
PROS

  • Solid wood
  • Can be refinished up to 5 times
  • Easy installation

CONS

  • Increased shrinkage effect when humidity levels decrease by 20% or more
  • Maximum recommended runs if stable humidity cannot be maintained: 15 ft across widths (tangentially) and 25 ft lengthwise (longitudinally)

 

 

ENGINEERED CLICK-LOCK BAMBOO FLOOR (is “floated”)


PROS

  • High dimensional stability
  • Can be refinished up to 2 times
  • Easy installation

CONS

  • Maximum recommended runs if stable humidity cannot be maintained: 25 ft across widths (tangentially) and 45 ft lengthwise (longitudinally)

 

 

SOLID TONGUE & GROOVE FLOOR (is nailed or glued down)

PROS

  • Solid wood
  • Can be refinished up to 5 times
  • No limit in distance of continuous runs of flooring when nailed or glued down. 
  • Can be floated using tongue and groove glue, however maximum recommended runs if stable humidity cannot be maintained: 15 ft or less tangentially and 25 ft or less longitudinally (lengthwise).

 

Ignoring The Humidity In Your Home and Your Geographical Climate

If you live in a geographic location with stable year-round humidity or your HVAC system can maintain constant humidity levels, you are unlikely to experience shrinking floors (unless you don’t acclimate them properly).   However if you live in an area where the humidity varies more than 15% throughout the year (and you experience seasons), you’re much more likely to experience expansion and contraction in your wood and bamboo flooring (this is normal), and the effect is increased exponentially in solid floating wood/bamboo flooring.  Unless you can keep your home’s interior relative humidity within a 10-%15% range year-round, you’re better off installing a solid tongue and groove floor via nail down or glue down installation.  Low interior humidity settings are a common cause of bamboo and wood floor shrinkage.

 

Not Knowing the Limitations of Floating a Solid Wood or Bamboo Floor (even the click-lock styles)

If you decide on solid click-lock bamboo flooring, you’ll need to take preventative measures to ensure your floors don’t shrink.  One measure is to install a break in your bamboo floor every 15 feet then install a t-molding and begin a new section after that. This step minimizes the radiating effect on the perimeter of your floors and subsequent pulling away from walls and gapping.

All bamboo and wood expands and contracts in response to humidity levels.  When the planks are nailed down or glued down to the sub-floor, each plank will expand and contract a tiny amount. This normal wood flooring behavior and is what causes gaps to develop between planks in the winter and those same gaps close in the summer.

Conversely, floating floors (where planks are all locked together but not secured to the sub-floor) will expand and contract as one entire unit. Each individual plank expands and contracts, but since no tiny gaps form between the planks (because they’re locked into each other and not secured to the subfloor), this expansion/contraction force gets pushed outwards (radiates out) to the outer edges of the installation.

Now picture a run of flooring consisting of 100 planks all clicked together and floating as one piece. If each individual plank contracts by just 1 mm, a massive shrinkage effect radiates out to the edges of the installation. After a few seasonal cycles of this effect, floors can separate from outer walls and planks can separate in the middle of rooms; when this happens eventually the whole floor needs to be taken up and re-laid which can be a costly repair.

 

IN SUMMARY

1) Choose a high quality bamboo flooring brand (do your homework!)

2) Choose the right type of flooring based on your maximum allowable runs

a. If your runs exceed 15 ft tangentially and 25 ft longitudinally, use either engineered floors, or tongue and groove floors that are nailed or glued down

b. If your runs exceed 25 ft tangentially and 45 ft longitudinally, use only tongue and groove floors that are nailed or glued down

3) Acclimate the floor properly (detailed in the installation instructions)

4) Install the floor as per the installation instructions

5) Maintain stable year round humidity in your home, between 40%-60% (once you get below 30% most wood floors will start to shrink noticeably or crack)

 

Want To Avoid Shrinkage?  Consider Engineered Click Lock Bamboo Floors or Tongue And Groove Bamboo Floors

Click lock engineered bamboo flooring consist of multiple layers which offer 3x as much dimensional stability as solid wood floors. If you live in a climate with seasons and you install a floating/locking engineered bamboo floor, you will still need to add breaks in your runs, but you have up to 25 feet or more to play with. Installing engineered bamboo floating floors means you won’t have planks that pull away from walls after a couple of cold winters.

 

How to Select a Reputable Bamboo Supplier

www.bbb.org

www.bbb.org

You should always do your homework before choosing a bamboo brand to purchase from. Use on-line review sites and the Better Business Bureau to find a reputable supplier you can trust and whose products are of the highest quality.

 

 

Eco-Friendly and Affordable Flooring

If you’ve done any research on bamboo flooring you know that it is environmentally friendly and usually costs less than traditional hardwood floors. Keep in mind that different suppliers have different standards when it comes to providing consumers with “green” products.

If you’ve been thinking about installing bamboo floors in your home but have been worried about potential shrinkage problems, we hope this article has helped you understand a bit better that it’s the quality of the product and the type of installation that will determine how stable it is.

 

Since 2005, Ambient Bamboo Floors is proud to be a leading supplier of hardwood bamboo products. We are A+ certified by the Better Business Bureau and committed to customer service excellence and product quality. All of our bamboo floors come with a lifetime structural warranty and finish warranty.  All of our bamboo products are engineered to meet only the highest standards. Our strand woven bamboo flooring has Janka Hardness ratings that far exceed any hardwoods, so it’s ultra-resistant to denting, scratching, warping and anything else an active family can throw at it!  Our bamboo is harvested from properly managed forests that reach maturity within 5-7 years. We are a member of the US Green Building Council, and many of our products qualify for LEED credits.   All of our bamboo comes from FSC certified forests. 


Categories: Flooring

6 replies

  1. Last year we had a bamboo board floor with the click and lock feature installed in our newly purchased condo. It is a continuous run all through most of the condo, probably 1500 sq ft. The wood was in the condo for at least 3 weeks prior to installation. Within a few months the boards began to separate in several places. In some areas it is minor but in others they have separated so much that they have “un-clicked” (unlike what you mention in your write up) and you can now see the concrete floor below. It is a floating floor. The contractor who selected and installed the floor continues to say it is the humidity problem but we have a humidifier on our HVAC system and now it is summer again and nothing has changed, in fact it continues to get worse. We took down some walls before we had the floor installed and love the open floor plan but the gaps in the floor are ruining our whole “bamboo” experience. Can you give us any advice on what we should do? Vicki

    • Hi Vicki,

      We’re sorry to hear about the problems with your floors! Did you consult the manufacturer’s installation instructions provided by the company that you purchased from, as related to maximum run limits, and also about the recommended interior humidity settings? If your interior humidity dropped below 35%, then your contractor may be correct in assuming that you have interior humidity issues.

      Otherwise, were the maximum run lengths on the page below followed? Did the manufacturer explain to you ahead of time or in their installation instructions that these run limits are required? At Ambient we make sure to inform our clients about maximum run limits, and we only sell click lock solid bamboo floors if the homeowner lives in a geographic climate with stable humidity or their home contains a well-functioning humidity control system.

      https://www.ambientbp.com/types-of-bamboo-flooring-solid-vs-click.php

      Regards,

      Jared

  2. Is bamboo suitable for Georgis heat and humidity. Looking into a solid strand click and lock by morning star. Is this brand high quality.

    • Hi Jarrod, thanks for your interest in bamboo floors. Our recommendation is to always do a search online for “complaints” and the brand you’re interested in buying, to determine whether that brand has problems or not. As to whether solid strand click floors are okay for use in Georgia, our response would be that it depends on how much your humidity levels change inside your home. Humidity swings can be the “Achilles Heel” of solid strand woven click lock floors.

      Here is a good page that will outline the types of bamboo floors, and what they’re suitable for: https://www.ambientbp.com/types-of-bamboo-flooring-solid-vs-click.php

      As long as you pick the right bamboo floor, it will give you decades of beauty and trouble free use. Good luck!

  3. Great article!

    I recently purchased US Floors bamboo flooring that is engineered, strand woven locking/floating. I want to install on lower level that is concrete and upstairs which is on plywood subfloor, both method floating.

    Right now the floors are all unboxed and cross-stacked on carpet room with temperate set at 73 degrees. Per manufacturers’ instructions optimal temperature is 70, for installation.

    Question – does this apply to both concrete and plywood?

    Also, I read in another blog a hardwood floor installer commented that for my type of wood he prefers to do glued-down and not floating.

    Question – What are the pros/cons in both methods?

    Last question – if I were to do floating, is it recommended to glue the tongue/groove so to prevent gapping in the future?

    • VL, thanks for your question. The most important factor in having a healthy wood (and bamboo) floor is to keep constant and stable humidity year-around, regardless of whether you float, glue or nail the floor. Solid floating bamboo floors that are improperly moisture balanced or exceed the maximum run limits are quick to show problems when there are extreme humidity swings as they will pull apart from each other and out from under walls.

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