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 several 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

Wet Bamboo. 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. Lower quality brands improperly moisture balance their floors, resulting in “wet” bamboo floors, which over time will lose their moisture and begin to shrink (especially in the winter time).

Run Limits Not Specified In The Installation Instructions. The floors that are most likely to experience shrinkage problems are solid click-lock floating bamboo floors. Often these floors have been either A) improperly moisture-balanced and/or B) sold to customers without informing them up front about humidity requirements. There are potential problems with these floors in variable humidity conditions (more on this below).

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 year-round humidity, or have a built-in humidity control system that will keep your interior humidity within a 20% range year-around, the maximum run limitations outlined below probably don’t 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.

** As a rule of thumb, long runs of flooring should always be glued or nailed down **

 

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 this floor when nailed down or glued down.
  • Typically nailed down or glued down, however can be floated using tongue and groove glue if stable humidity cannot be maintained. If you choose to float this floor in an environment with fluctuating indoor humidity, we recommend the following maximum run distances: 15 ft tangentially and 25 ft longitudinally (lengthwise).

 

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 indoor humidity cannot be maintained: 15 ft across widths (tangentially) and 25 ft lengthwise (longitudinally)

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

Engineered Click Lock Bamboo Floor With HDF Core

Engineered Click Lock Bamboo Floor With Multi Ply Eucalyptus Core

PROS

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

CONS

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

 

WHEN YOU DON’T HAVE STABLE HUMIDITY – FOLLOW THE RUN LIMITS

engineered-run-limit-diagram-floating-bamboo-flooring

 

solid-run-limit-diagram-floating-bamboo-flooring

 

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 your home’s interior relative humidity stays within the same 15-20% range year-round, it’s always recommended to install a solid tongue and groove floor via a nail down or glue down installation. Low interior humidity settings are a common cause of bamboo and wood floor shrinkage.

Floating a Solid Wood or Bamboo Floor – Know The Limitations

Like Hary Callahan said: “A man’s got to know his limitations.” All bamboo and wood expands and contracts in response to humidity. When floor planks are nailed or glued down to the sub-floor, each plank will expand and contract a tiny amount. This is normal wood flooring behavior and is what causes small gaps to develop between planks in the winter. 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 consecutive run 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.

If you decide on solid click-lock bamboo flooring, make sure you have stable indoor humidity. Otherwise you’ll need to take preventative measures to ensure your floors don’t shrink, such as having a break in your floor every 15 feet (use a t-molding where possible). This step minimizes the radiating effect on the perimeter of your floors and subsequent pulling away from walls and gapping.

IN SUMMARY

  1. Choose a high quality bamboo flooring brand (do your homework!).
  2. If you live in an area with dry winters and humid summers (or vice versa) and you don’t have interior humidity control, you should nail down or glue down the floor instead of floating it. If your runs are less than 15 ft wide X 25 ft long you can probably float the floor, but still a risk.
  3. Acclimate the floor properly, as per the manufacturer’s guidelines. If you’re in a dry or humid geographical area, add on 3-4 days extra for acclimation.
  4. Install the floor as per the installation instructions.
  5. Maintain stable year round humidity in your home, between 40%-60%.

 

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 changes in humidity from winter to summer, you’ll want to choose this type of floor over a solid wood click lock product. Installing engineered bamboo floating floors means you won’t have planks that pull away from walls after a couple of cold winters (as long as the recommended run limits are maintained).

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, 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

25 replies

  1. Thanks for the valuable information. Regarding acclimation and humidity issues with such flooring, I wonder if the strand engineered bamboo might not be a wise choice here in the southwest where humidity can be as low as 10 percent at some times during the year while reaching 30 to 50 percent for short times during our monsoon season. Shall we be looking at other options?

    • An important factor in having a long last wood or bamboo floor is to maintain stable humidity conditions year around. While wood and bamboo is installed in all types of climates around the world, interior humidity settings between 35%-55% should be maintained.

  2. Question: Can you use a steam cleaner on a bamboo floor.
    anna

    • Hi Anna! No, we do not recommend cleaning bamboo floors with a steam mop. In fact, you should never use a steam mop on any hardwood floor. It may not damage the floor immediately, but repeatedly infusing wood with humidity/water vapors can damage the finish and dimensional stability over time. While bamboo flooring is more water-resistant than traditional hardwood floors, steam mops can destabilize wood and even bamboo cellular structures; which over time could result in shrinkage, warping, buckling and even cracking. Here are some good tips on how to effectively clean your bamboo floor: https://www.ambientbp.com/blog/best-practices-for-cleaning-your-bamboo-floors

  3. Hi, i live in Hilo on the big island of Hawaii. I’m getting confused on what bamboo floor i can use here. Can you recommend something for me?
    Thanks!

  4. Our bamboo engineered floor buckles. Recently it has developed large waves. We live in an area where the humidity fluctuations range widely. (Today it is 60% with a tempature of 70. Yesterday it was warmer so we used the HVAC and the humidity went down to about 45%). The flooring was chosen by the previous owner and, from the comments above, probably the wrong choice for this area. Will the buckling go away if we us a dehumidifier to control the humidity? I guess the alternative is to replace the floor.

    • Hi Steven, sorry to hear about the floor problems you’re having. Do you know who the manufacturer of that floor is? If so, we recommend calling them directly for advice. Without being able to inspect the site personally it’s difficult for us to advise you on how to fix your problem. That being said, bucking/crowing is usually a result of too much moisture/humidity in the room itself, and cupping is usually a result of excessive moisture hitting the bottom of the floor. Whether you use a humidifier or dehumidifier depends on whether the floor is cupping (use a humidifier) or buckling (use a dehumidifier). Here’s a great article from the NOFMA about wood/bamboo floor cupping and buckling.

  5. I am getting ready to install a 20 X 14 engineered bamboo floor. I am wondering if i can glue it vs letting it float, the flooring has acclimated for several months in the house.?

    • Hi Joe, we recommend checking with the manufacturer/brand of your floor about the best installation method; however usually engineered floors can be floated, glued or nailed with no problem (depending on the sub-floor). You’ll just want to make sure the sub-floor is level, dry and clear of debris. Good luck and enjoy your new floor!

  6. Hi,

    I have installed bamboo flooring in our house. The humid condition in our area are very high as we live near the sea.

    Now our flooring has started darkening, a few planks only, it is carbonized flooring. The grains have suddenly turned black. I don’t know the reason. Can you please help and give us a solution.

    Neeraj

    • Hi Raj! If the wood itself is darkening you most likely have a sub-floor moisture issue – your floor may be getting wet from underneath. If you have a concrete subfloor or a crawl space, it may not have been properly sealed. We recommend hiring an NWFA-Certified flooring inspector to come check it out, they’re very experienced and will assist you in determining your best course of action. Hope that helps and good luck!

  7. Hi,

    I had bamboo flooring installed on top of the existing tile (click installation) about 10 months ago. I don’t think the person that installed it let the floors acclimate to each room. I live in Fort Lauderdale and my ac is automatic. For the past few weeks we’ve experienced colder temperatures than usual and the ac hasn’t been on at all. This morning I noticed that right outside my bedroom (by the door, right underneath where the door shuts) the floor had risen (I want to say the floor expanded and when I step on it the floor rises right on the outside of the bedroom door). Is there any way to fix this without having to replace the floor ? I’m guessing the humidity in the house got higher than normal which caused the floor to expand ? What do you recommend. Thank you

    • Hi Maria! First we recommend reaching out to the manufacturer of your floors to see what their advice is in terms of recommended action and/or humidity levels. Otherwise, we recommend purchasing a hygrometer like this one to make sure your humidity levels haven’t dropped too much. Oftentimes during unseasonably cold weather the humidity can drop and it can cause all types of hardwood flooring to shrink a little bit, which is what may have caused your planks to bow. With a floating floor you want to avoid gluing parts of it down unless the runs are really short in the problem area, so we recommend putting a humidifier in that room until the humidity increases again, and the planks will most likely retain their shape.

  8. We installed bamboo flooring a year ago and just recently it has started separating.We acclaillation. it for a week before installation. It is a floating floor.

    • Hi Marlene! We recommend contacting the manufacturer of your floor when something like this happens. Is it a solid (bamboo all the way through) floor? If it was acclimated correctly and installed correctly (with 1/4″ to 1/2″ expansion gaps around the perimeter), then the culprit can be a few things: 1) your indoor humidity has dropped too far or 2) the brand you purchased didn’t properly balance the moisture in the floor during manufacturing.

      We recommend that you pick up a digital humidity monitor like this one at Home Depot to check your indoor humidity. If the reading is below 35% we recommend putting a humidifier into the space for about 3 weeks to see if the problem corrects itself. If the planks have separated to the point where they’ve unclicked from each other, and the humidifier doesn’t fix the issue, the only solution may be to take the planks up, click them back together and put them back down.

  9. Hi,
    I am thinking about installing a “click” bamboo floor.
    It said that it can be glued to the sub floor or floated.
    If I decide to float the floor, is there a problem if I decide
    to use tongue and groove adhesive. Is there a problem
    with gluing the tongue and groove of a click floor?
    Thank you

    • Hi Don,

      If you’re installing a click lock bamboo floor that means you shouldn’t need tongue and groove glue because the planks will simply “click” into each other. For a good understanding of click vs tongue and groove I recommend you check out our bamboo flooring types page.

      In regards to gluing down a click lock floor the answer is yes, you can glue down a click lock floor, it’s just a little more labor intensive as the glue may come up through the butt ends of the planks a bit more than a glue down job using tongue and groove planks. As always when gluing down a floor you’ll want to make sure to use Bostik Adhesive Remover Wipes to remove any spilled glue before it dries. Also, if you’re gluing down over concrete or over a crawl space you may need to take a few extra precautions. Hope that helps and best of luck!

      • Hi Jared,

        First thank you for responding and I understand I shouldn’t “need” tongue and grove glue
        with a click floor but my question was is there a problem if someone does use tongue
        and grove glue with a click floor?
        If a person does use a tongue and grove glue with a click floor, what are the possible
        failures if any? If you have never heard of anyone doing this, that is ok.
        There is a click hardwood floor that I saw and was curious if someone
        also used tongue and grove glue on this click floor would there be a benefit? A failure?
        Or there would be no benefit or failure at all? Just thought maybe there would be a benefit
        to putting tongue and grove glue in the grove of the hardwood click flooring.
        Maybe make it more stable.

        Thanks again Jared

        • Hi Don,

          The question about whether you can use tongue and groove glue on a click-lock floor should be directed to the manufacturer of your floors, and we cannot speak to the effectiveness of this method on other flooring types or brands. At Ambient Bamboo Floors we don’t advise using tongue and groove glue with our click lock floors because the possibility exists that it can compromise the locking system if not applied in careful quantities. Hope that helps and have a great day!

          Regards,

          The Ambient Team

  10. Hi,

    We installed Golden Arowana from Costco in 2012 (6 years ago). There is one section where a gap of about 1/8″ has developed. Any idea what may have caused this? It’s in the middle of the floor, so I am not sure how to go about fixing the problem.

    Thanks,
    Kerry

    • Hi Kerry!

      Sorry to hear that! There are a variety of factors that can result in gaps in hardwood, including low humidity in your home, shifting of planks on an uneven subfloor, and more. On floating floors sometimes you can use a racking system to tighten the planks, but if that doesn’t work then you may need to pull up and replace planks in that area. If it’s only happening in one area that points to a sub-floor or installation issue and I would contact a local NWFA-certified inspector or installer to come out and review it so that you may determine a course of action. Good luck and let us all know what happens!

      Regards,

      The Ambient Team

  11. Can you please send me a list of quality bamboo flooring brands
    Thanks

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