Can Drywall Tape Be Used On Cement Board?

Have you ever been in a situation where you had to fix your walls and you were confused by whether you are allowed to use drywall tape for cement boards or cement board tape for drywalls, and just got confused about which tape can be used for what? It can be a bit confusing, but it is important to know which tapes can be applied to which walls. So, can one use drywall tape on cement board as a substitute for cement board tape?

Drywall tape should not be used on cement board. The thin-set mortar, which is used with cement board, has detrimental effects on the tape. Thin-set mortar degrades certain types of tape, which is why the tape you use must possess alkali-resistant properties – something drywall tape does not have.

When applying the tape, it is important to know which tape you must apply for which reason. There are various types of drywall tape, each with its different functions. So, can you use drywall tape on cement board? Other questions also arise: if drywall tape cannot be used on cement board, which tape can be used on cement board? Additionally, If drywall tape cannot be used on cement board, where must it be used? What happens if you have a situation where drywall and cement board must be taped together? All of this we explore!

Can Drywall Tape Be Applied To Cement Board?

Before we start discussing whether or not drywall tape can be used on cement board, let us first discuss what drywall tape is and what it is used for. Drywall tape can be described as a tape that is designed to fit into and cover the seams (or joints) of drywall.

If we take a look at a tape such as the FibaTape Mold-X10 Drywall Tape, we see that it is a fiberglass mesh drywall tape with mold-resistant properties. It is perfect for environments that are moist and prone to mold build-up. Thus, it offers a lot of protection when you find yourself in a very humid environment.

That said, this mesh tape is NOT meant for cement boards. It does not offer any particular protection from the degradation that occurs when in contact with thin-set mortar because it does not have the alkali-resistant coating that comes with cement board tapes. Accordingly, it is best to use drywall tapes – be it mesh, paper, or any other kind of drywall tape – on drywall.

Given the different properties of drywall tape, it must be noted that there are various drywall tapes that should be used in different scenarios; none of these scenarios, however, include using them on cement board.

What Tape Should Be Used On Cement Board?

Now that we know that drywall tape is not ideal and must not be used on cement board, what are the tapes that you can use? We explore that now. It is important to remember that cement boards (or any similar products for that matter) are substrates for tiles. These tile-like products are often applied with thin-set type mortar (the glue that sticks the tile).

With this in mind, FibaTape Cement Board Tape is the only cement board tape that must be used when it comes to thin-set or dry mortar. FibaTape Cement Board Tape is alkali resistant and is also made from vinyl-coated fabric that can be found in certain cement board’s faces. Because of this, FibaTape Cement Board Tape provides additional crack resistance and strength to the cement board.

Because FibaTape Cement Board Tape possesses alkali resistance, the fiberglass is protected from any degradation which the thin-set mortar can cause.

If Not On Cement Board, When Should Drywall Tape Be Used?

Paper drywall tape has very limited use in that it is almost purely aesthetic: paper tape is used to cover the seams of drywalls that have ‘drywall mud’ applied to them. The idea is to first feather out the drywall mud, such that it is difficult to exactly see where the compound starts and where it stops. Thus, the idea is to get it as thin as possible.

Because this compound dries up eventually, you can see the seams again. In order to give your drywalls a rounded finish look, you then apply the paper tape. Once the paper tape is applied, you apply another tiny layer of compound over the paper tape to smooth out bubbles and edges. This makes it difficult to see where the seams of your drywall start and stop. It gives the impression that it is one holistic wall, as opposed to separate panels joined together.

Other drywall tapes serve very similar functions, only with an added benefit of protecting the seams against potential mold build-up, strengthening the seams against fire, etc.

What Tape To Use Where The Drywall Meets Cement Board

It is clear when one has to use which tape for which type of wall in isolation, but what if the situation is a bit blurry and a mix of two different types of wall that need taping?

When dealing with a scenario where the drywall and the cement board meet, you can use fiberglass mesh tape. In this instance, you use a setting type compound for joints and apply the mesh tape to the compound.

To do this, take your mesh tape a run it horizontally along the seams of the cement boards. You have to be careful to ensure that the tape remains flat. Thereafter, you can merely finish the drywall side with the compound and tape you would normally use for drywalls.

Can Cement Board Tape Be Used On Drywall?

Some suggest that it is not a good idea to use cement board tape on regular drywall because cement board tape should be placed in thin-set mortar, which is very different from a drywall joint compound.

Multipurpose Tape That Can Be Used For Drywall And Cement Board

We have no explored whether or not drywall tape can be used for cement boards and whether cement board tape can be used for drywalls; it appears that the answer is no for both of these scenarios. It is best to use the tape on something which it is designed to be used on and leave it at that.

The question that arises, however, is whether or not there are any tapes out there that can, perhaps, do both? It appears we are in luck because the Grabber Mesh Tape 2” x 300 is perfect for someone who is too lazy to go and look for two separate tapes for two different types of walls (or boards).

The Grabber Mesh Tape 2” x 300 is certified in terms of ISO 9002 as a multipurpose mesh tape that can be used for finishing drywall as well as cement board! It is designed to cover regular joints in drywalls, racks, popcorn finishes, and many more!  This mesh tape is a self-adhesive fiberglass tape that is ideally suited for environments where there is heat or humidity.

Final Thoughts

Now we know that there is drywall tape and cement board tape, each with its own designs and intended usages. Drywall tape, for the most part, is only used to give your wall that finished look and provides for a bit of water resistance and strengthened seams. Accordingly, drywall tape should, as the name implies, only be used on drywall and not be repurposed for any other types of wall.

On the other hand, there is cement board tape. This tape comes with a special alkali-resistant property that makes it ideal for cement board tape. Thus, as the name implies, cement board tape should ideally only be used on cement boards.

Accordingly, Drywall tape does not work on cement board because it does not have alkali-resistant properties. Use an approved cement board tape, such as the FibaTape Cement Board Tape, that ensures that when you do cover the seams of your cement board, it won’t come apart not too long after!

If you find it too much of a chore to figure out which type of tape to buy for which type of wall or board, you can always just buy multipurpose tape, such as The Grabber Mesh Tape 2” x 300, and you will never go wrong!

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