Can You Use AquaDefense On Drywall? (Explained)

Drywall is highly vulnerable to water damage. It’s why you may be considering using a waterproofing product such as AquaDefense. This product falls in the same category as RedGard.

It serves as a waterproofing crack isolation barrier. And, you can apply AquaDefense on drywall. But, is it advisable? Keep on reading to find out.

Interior construction of housing project with drywall installed and patched without painting applied interior with drywall installation and construction work in progress

Will AquaDefense Stick to Drywall?

It absolutely will. AquaDefense is available in liquid form. You can apply it over drywall using a roller brush.

AquaDefense will adhere to the drywall and create a waterproofing barrier if given enough time to cure. However, it’s not recommended to use AquaDefense on drywall.

Why Shouldn’t I Use AquaDefense on Drywall?

To understand better why AquaDefense shouldn’t be used on drywall, let’s look at why you may consider using it in the first place.

AquaDefense is a waterproofing product made by Mapei. It’s a quick-drying membrane made of advanced liquid rubber.

AquaDefense creates a waterproofing crack isolation membrane when applied on a surface, which is ideal for tile installation.

Therefore, you may be considering using AquaDefense on drywall to create a waterproofing crack isolation membrane for tile installation.

But the problem with drywall is that it should not be used in a wet or high moisture area. Of course, drywall can be tiled over as long as you perform adequate prep and use the correct mortar.

When you use AquaDefense over drywall in an area that frequently experiences moisture, the drywall will be severely damaged at a certain point in the future. And the repairs will be pretty costly.

Therefore, the bottom line is that AquaDefense shouldn’t be used on the drywall in a high-moisture area such as a kitchen or bathroom.

If you intend to tile a typical room such as a bedroom, you don’t need to waterproof drywall with AquaDefense.

Replace Drywall with Cement Board and Then Apply AquaDefense

People have a common misconception that it’s okay to use drywall in a shower system as long as it’s waterproofed.

A shower setting is pretty complex, and the consequences can be severe when you make a mistake. Drywall can easily be damaged by water. Having drywall in your showers can also lead to mold growth.

What if you waterproof it with AquaDefense? Sure, when drywall is waterproofed, it can be shielded from moisture.

For AquaDefense to work, you must ensure there is no seam or opening that may leak water into the drywall substrate, which is almost impossible.

Even with AquaDefense, drywall can be exposed to moisture that seeps through the underfloor.

When that happens, the drywall will deteriorate and welcome mold into your home. The repairs will be pretty expensive, and your health will be at risk because of the mold in the walls.

Instead of taking such a huge risk, drywall in a shower area or any high moisture area should be replaced with a cement board for the application of AquaDefense.

Unlike drywall, cement board is pretty durable and moisture-resistant. No matter how wet it gets, it will hold its shape and won’t deteriorate.

Using AquaDefense on drywall may seem like a convenient shortcut to waterproof drywall. But leaks are inevitable. To be safe, switch to a cement board instead.

MAPEI AquaDefense

Can You Use AquaDefense on Moisture-Resistant Drywall?

AquaDefense shouldn’t be used on regular drywall because it can get damaged when moisture seeps through. But with moisture-resistant, popularly known as green drywall, you can use it in the bathroom.

But you should remember that green drywall isn’t 100% moisture-resistant. Exposure to too much water will damage it.

What Product is Recommended for Showers with Drywall?

From the above, it’s clear that AquaDefense isn’t recommended for use on showers with drywall. That’s because the drywall will eventually get damaged by moisture as it seeps through other areas.

Therefore, you are probably wondering, what waterproofing product can I use on showers with drywall?

First, it’s important to mention that installing drywall in a shower or high-moisture area is an amateur move. No professional or experienced contractor would use drywall in a wet area, whether moisture-resistant or not.

To emphasize one more time, drywall doesn’t do well when exposed to water. If you discover drywall in your shower, it’s better to replace it with a cement board since it’s more durable.

But if you prefer to go ahead with waterproofing the drywall, you shouldn’t use AquaDefense. There is another waterproofing membrane that is approved for use on drywall, and it’s known as Kerdi.

Made by Schluter, Kerdi is one of the best waterproofing membranes out there. It will protect the drywall from moisture damage if you use it on the walls and shower pan.

But if you leave any openings, there is a chance that some water may seep through and damage the drywall. If you prefer to compare Kerdi with another product, you can check out DITRA. It’s also a remarkable waterproofing membrane.

Will AquaDefense Protect Drywall from Moisture?

AquaDefense is a waterproofing product. It’s one of the best in the market. For those who insist AquaDefense will protect drywall from moisture, you need to understand that you are only postponing the inevitable.

All waterproofing products wear out after a while. That means, even though AquaDefense will shield drywall from moisture in the next year or two. Eventually, it will wear out, and moisture will get in. That’s when hell will break loose in your bathroom.

Drywall can be protected from moisture by AquaDefense. But this will only last for some time. It’s better and safer to use a long-term solution such as a cement backer board that won’t deteriorate when water accidentally leaks through.

Will More Coats of AquaDefense Protect Drywall from Moisture?

Not really. Mapei recommends that only two coats of AquaDefense be applied over a surface. Applying many coats can cause the waterproof membrane to fail prematurely.

Therefore, there won’t be any benefits that will come from using lots of AquaDefense on drywall. Also, even if you apply plenty of coats, how will you prevent moisture from passing through the shower pan?

How to Apply AquaDefense on Drywall?

Now that you know the limitations of using AquaDefense on drywall, you need to choose whether to pull off the drywall and use a cement board instead.

Or, you will proceed with drywall and live with the risks. If you settle with the latter option, here is how to apply AquaDefense on drywall.

Step 1– Start by applying the AquaDefense on joint lines. The joints act as entry points of moisture. They need to be sealed thoroughly.

Step 2 – Cover the joints with Mapei band tape. The membrane by itself isn’t enough to cover the joints on drywall. This is why the joints must be reinforced with tape. Cut the tape and ensure it evenly covers the joints. Install the tape when the AquaDefense is still tacky. That way, it can dry with the tape on.

Step 3 – Cover the tape with more AquaDefense. This is to ensure adequate adhesion.

Step 4 – Grab a roller and apply thick AquaDefense on drywall. A roller makes the application easier. Give the first coat an hour to dry before applying the second and final coat.

Step 5 – Give the surface a day to dry, and you can tile over it after.

Please note that we don’t recommend using AquaDefense on the drywall in wet areas. If this is a project you plan on starting, it’s better to replace the drywall with a cement board and then apply AquaDefense on it.

Can You Tile Over Drywall Sealed with AquaDefense?

One of the perks of using AquaDefense is that you can easily tile over it. However, you must be cautious when tiling over drywall sealed with AquaDefense.

If the tiling is being done on the drywall in a shower, moisture will seep through and damage the substrate. When the drywall substrate is damaged by water, the tiles will fail, and you will have wasted plenty of resources.

If you plan on tiling over drywall, ensure that you take note of the conditions the room will experience. If it’s a usual room with no moisture, you can tile it and don’t even need to use AquaDefense in the first place.

But if it’s a wet area, remove the drywall and replace it with a cement board. Initially, it may seem expensive. But it will save you a lot of money and time.

Should I Hire an Expert to Install AquaDefense Over Drywall?

Regarding AquaDefense and drywall, it’s not a matter of expertise. It all depends on the presence or absence of moisture in the room where these two products will be used together.

On the contrary, when you hire an expert constructor, they will inform you that drywall isn’t a suitable substrate for tiling in a shower or kitchen.

They can even tell you that using drywall in a shower is against the local building codes, depending on where you are staying. Bringing in a qualified expert can save you a lot of trouble.

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