Bamboo Flooring Contraction and Expansion
Bamboo continues to prove itself as one of the top choices for flooring materials in all sorts of different homes, offices, and even commercial spaces. But no matter how popular this product is, there are still common flooring problems to prepare for, such as contraction and expansion. If the proper precautions are ignored, you could end up with some serious problems down the road – plus the need for some new bamboo floors!
Why does bamboo flooring expand and contract?
Since bamboo flooring is a natural product (read more about its eco-friendliness), it is affected by the elements, including the seasons, temperature, and humidity. When the humidity level is high, the bamboo absorbs the moisture and expands. Once the humidity levels drop, the bamboo will contract, or shrink, back to its normal size.
Don’t think you’re getting a subpar product because of the expected expansion and contraction – all hardwood floors (along with other natural building materials) do this, because they are indeed living! Any hardwood owner knows that in the winter, the cracks in the flooring may be a little more noticeable and creaky, while in the humid summers, they’ll be expanded and quiet.
How to reduce bamboo flooring expansion and contraction?
While there is no way to completely eliminate the natural expansion and contraction of bamboo flooring, there are ways you can keep it under control and make sure you’re not damaging anything in the process.
1. Acclimation
Before installation, it’s vital to give the bamboo flooring plenty of time – a minimum of 72 hours – to adjust itself to room temperature. To do this, simply bring the pallets of bamboo flooring into the exact room or area where it will be installed.
Leave it there for at least three days, and up to ten days, so it can completely adjust to the temperature and humidity level. You’d be surprised how much the humidity levels vary from room-to-room in the same house, so make sure you’re showing the bamboo exactly where it will be living before its installed.
For additional advice on installing bamboo flooring, check out our Installation Guide.
2. Expansion Gap
The next thing to do is to leave a gap around the entire parameter of the room (this is often called an “expansion gap”) with the bamboo flooring. This small space will give the bamboo room to properly expand and contract, without causing any damage to the flooring.
If there is no gap for the bamboo planks to expand, they will still expand – only upward, causing buckling, distortion, and sometimes permanent damage. This is not the route you want to travel!
How big of an expansion gap should you leave?
- This depends on the type of bamboo flooring and the size of the area
- Could be anywhere from 6mm-13mm (1/4in-1/2in) from each wall or structure*
- If the room or area is very large, leave tiny slots between each plank*
- Don’t forget to leave a gap around permanent fixtures, too! This includes counters, islands, doorways, and built-ins.
*Be sure to consult with your bamboo flooring provider to get the proper gap measurements and instructions for the specific type of flooring you’re installing
It probably sounds a little weird to leave gaps in your beautiful bamboo flooring, but it’s not only common practice, it’s a best practice. This will save you from permanent damage and keep your floors looking great, even years down the road.
Expansion gaps are so common in fact; you can purchase products to cover them up and have a floor that looks seamless and sleek. Most rooms call for a t-molding, which covers the expansion gap while still leaving room for expansion and contraction, and looks like a standard molding or baseboard.
3. Water & Humidity
If you live in an area where there is relative humidity (35-55 percent) all year long, bamboo flooring is less-likely to experience expansion and shrinkage. An HVAC system can also assist with this, as can a dehumidifier – or possibility a humidifier if you’re lucky enough to live in a dry climate.
Lastly, take proper care of your bamboo floors by cleaning them with a recommended cleaner (which will likely not be water-based), and clean up spills as quickly as possible.
Material quality: how it affects expansion and contraction
As with any other kind of building material, different quality levels of bamboo flooring can mean more or less expansion and shrinkage. To choose the best quality of bamboo flooring for your project, you’ll have to consider:
- Budget
- Local seasons
- Temperature
- Indoor/outdoor humidity levels
- Expected wear (pets, children, office area, etc.)
Local Seasons & Temperature: how it affects expansion and contraction
In general, high-quality bamboo will be able to withstand higher humidity levels (within reason), and lower-quality bamboo will not. But it all depends on the needs of the project and the best product for it.
Areas of the country that experience four distinct seasons may also have an ebb and flow to humidity levels which can affect bamboo more than in the areas where it stays more or less humid throughout the entire year.
In those year-long humid areas (particularly the South), bamboo flooring is less likely to expand and contract after its acclimation period. In other parts of the country, the material is constantly having to adjust, i.e. and move right along with it.
Characteristics of High and Low Quality Bamboo Flooring
| High-Quality Bamboo Flooring | Lower-Quality Bamboo Flooring |
|---|---|
| Harvested at 5-7 years old | Harvested at 3-5 years old |
| 6-8% moisture | 8-12% moisture |
| Heavier in weight, hard | Lighter in weight, soft |
| Dense with actual bamboo | Not as much actual bamboo |
| Multiple coats of finish | Less than three coats of finish |
Checklist: Bamboo Flooring Expansion and Shrinkage
Once you’ve started your research and are really considering using bamboo as your flooring of choice, consult our checklist to make sure everything runs smoothly so you can enjoy your bamboo floors for years to come!
- Purchase the right type and quality of bamboo flooring
- Let flooring acclimate in installation location for at least 72 hours
- Leave an expansion gap beside walls and permanent structures
- Manage indoor temperature and humidity levels
- Clean bamboo floors with a recommended, non-water-based cleaner
- Take care of spills and additional moisture as soon as possible
There are many, many different types of bamboo flooring available for use and each one of them have different pros and cons. It really just depends on what you’re looking for on any specific project. Take a look at our comprehensive list of bamboo flooring suppliers when you’re ready to order!