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Do you need Underlayment for Bamboo Flooring?

Last updated on July 17th, 2021 at 08:51 pm

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If you’re planning on installing new bamboo floors, during your research process you likely have asked or have come across the question: Do you need Underlayment for Bamboo Flooring?

In general, the answer is yes, depending on the installation method. If you are planning on using the glue-down method, then underlayment is not a necessity. If you are using either one of the two additional popular installation methods (i.e. floating or nail down), then you will almost certainly need underlayment.

Installing your bamboo floors helps in numerous ways, including soundproofing, providing stability and durability, and additional protection from moisture. Underlayment can be installed over surfaces like concrete, other types of wood floors, and even vinyl tile.

In case you are in a hurry, here are my top 3 suggestions:

What are the main benefits of underlayment?

At a high level, underlayment is a material that is used to lay over the top of the subfloor before installing your final flooring material. A subfloor is the bottom layer of flooring in your space and is normally made up of a material such as concrete or plywood.

You will place it over the subfloor and with its primary usage to provide support for your top flooring surface.

There are a number of key benefits that come from installing bamboo floors over an underlayment. Here are our top four benefits:

1. Protects From moisture

Bamboo flooring has the tendency to retain moisture. When you install underlayment under your floors, you will protect them from moisture.

PRO TIP: I highly recommend install underlayment with a vapor barrier for ultimate moisture protection.

2. Helps with soundproofing

Another advantage is that underlayment provides great sound absorption and helps to prevent squeaking of your bamboo floors. If you live in a space that has a tendency to echo off sound (like music or sound from your television), the underlayment will help to minimize the sound as much as possible.

This is especially useful for spaces like apartments, townhomes, and condominiums, which are typically in close proximity to other homes.

PRO TIP: Best underlayments on the market are equipped with Ratings in their description. Look for Sound Transmission Lost rating or in short (STC). Over 65 is considered really good.

3. Helps to hide many of the flaws on the subfloor

Often, the subfloor in space is the flooring layer that has the most visible flaws, scratches, and marks, as this is the layer of your floors that is the least likely to be seen. On many occasions, your subfloor will also have dips, which can be a nightmare if attempting to install bamboo floors directly on top.

These dips in the floors can lead to the separation and cracking of the top flooring layer. In addition, the bamboo floors will begin to make noise, which can be problematic for years to come.

In order to help with concealing some of these flaws and limiting some of the downsides, you can install underlayment on top of the subfloor, which, when installing bamboo floors, will offer an additional layer of protection from the previously mentioned imperfections.

4. Provides stability to the top flooring surface

Underlayment also provides stability for your bamboo floors by making the existing flooring surface more flat and even. As mentioned above, the sturdiness that underlayment provides limits the amount of dipping and bending that will happen when walking on bamboo floors.

Do you need Underlayment for Bamboo Flooring

Types of underlayment used for bamboo floors

Because the two main installation methods that require underlayment are the nail-down method and the floating method, let’s take a look at the primary or most popular underlayment for each installation method.

Felt paper underlayment for nailing bamboo floors

Felt paper underlayments are common when installing bamboo floors using the nail-down method. Most flooring professionals use a 15 pound felt paper, which is also referred to as roofing paper, for those familiar with this type of paper used for other projects.

Although also referred to as red rosin paper, this paper type is typically used less often than felt paper because it tends to scatter hard-to-remove red dust which can stain walls and other materials.

NOTE: There are some professionals and individuals installing felt paper underlayment that consider felt paper to also be a vapor barrier, this is typically found to be untrue. 

While felt paper helps with preventing moisture from coming in contact with the bamboo flooring planks, it does not act as a complete vapor barrier. Therefore, if you’re planning on installing bamboo floors in wet, moist, or humid areas (like basements and bathrooms), it is recommended that you consider your installation method, which will potentially alter the type of underlayment you use.

Foam/cork underlayment for floating bamboo floors

The most common method used when installing bamboo floors is the floating method, which means that the bamboo strips are not fixed to the floor, but instead, they are joined together. For floating a bamboo floor, you will need an underlayment that is cushioned. These underlayments include materials like foam, cork, and rubber.

Although bamboo flooring is extremely durable when compared to other flooring types (such as hardwoods), it is prone to absorbing and locking in moisture, which can cause significant wear and tear.

Unlike the felt paper underlayment described above, a foam or cork underlayment can actually act as a moisture barrier. In addition, most best-rated underlayments already include vapor barriers.

No matter what the climate is like in your area, the subfloor will almost certainly have some moisture issues. Because of this, it is very important to line the subfloor with a vapor barrier to protect it from moisture completely.

KEEP IN MIND: If you're planning to install your bamboo floors over a heated surface, you will want to make sure you're using underlayment which is at least 2mm thick in order to insulate the floor and protect it from heat. 

Finally, you may find information that suggests that foam or cork underlayments can be used when installing bamboo floors using the nail down method, but this is not recommended. Because foam/cork underlayment tends to compress when walked on, it may produce squeaky noises over time.

How to install underlayment?

Now that we have discussed the benefits and types of underlayment for bamboo floors, we wanted to provide a brief overview of the installation process. Since many bamboo floors are installed using the floating method, the steps provided below will be the focus of this section.

Foam Underlayment

1. Rool out the Underlayment

Start by rolling out the underlayment sheet along any one wall while keeping the moisture barrier on the downside. Keep turning the foam while rolling it out.

Normally, the moisture barrier is marked on the sheet itself, but you should check the user manual if it is not visible. Look for the barrier mark carefully before rolling it out, as often time the manufacturer will roll up the product first during the production process and will then attach the barrier on the outside of the roll.

Because of this, the barrier will potentially be laid against the floor when you roll it out. Additionally, some manufacturers keep the barrier on the inside of the roll to prevent it from flipping. In these situations, you simply need to flip the roll before unrolling it.

2. Cut the foam

Cut the foam from the end of the row using a sharp utility knife and leave about 4 inches extra for overlapping with the walls.

3. Unroll another Foam Roll

Unroll another row of foam underlayment while overlapping it with the edges of the first row. Overlapping is important, otherwise the rows will slip off.

4. Join your underlayments with seam tape

Take the foam underlayment seam tape and apply it over the seam of two rows in order to join them. If you are not given a specialized foam underlayment seam tape, you can also use normal duct tape.

5. Repeat until the floor is covered

Repeat the process until all the floor is covered with the underlayment and seal it nicely. Avoid sticking the underlayment to the walls around the perimeter.

Installing Cork Underlayment

  1. Start by unrolling the cork along one wall of your room and then cut off the extra sheet from the end of the row using a utility knife.
  2. If the edges of the underlayment are curled, then flip it down as the edges should always face down.
  3. Unroll the next row and repeat the same process of cutting the extra sheet from the ends.
  4. Secure the seams using a cork underlayment tape or simply use duct tape. Seal the adjoining seams carefully.
  5. Repeat the same process until the entire floor is covered and keep sealing the seams using duct tape or underlayment tape. Also, keep trimming the excess product if necessary.

Additional underlayment installation tips

  • Be sure to use the utility knife very carefully as it can ruin the roll by tearing it.
  • If you’re planning on installing a floating bamboo floor on a concrete subfloor, then start by lining the subfloor using a plastic underlayment moisture barrier sheet and seal it properly. Install any underlayment only after performing this step because concrete floors are prone to giving off moisture.
  • Sometimes the foam or felt underlayment comes with in-built self-adhesive adjoining seams. To work with this type of underlayment, unroll the sheet while overlapping it the same width as the self-adhesive edges.
  • In cases where your walls have slight imperfections (e.g. they’re crooked or chipped off), then take a few extra inches from the underlayment and line the edges of the wall.

Wrapping things up

We know that underlayment can often be a tricky topic to understand, especially for those who are completely unfamiliar with what it is used for and why it’s important.

We hope that this article has helped to clear things up and has helped to show the benefits that underlayment provides for bamboo floors.