Should You Sheetrock Behind a Bathtub?

Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.

Finding suitable materials for a bathroom renovation can be tricky, especially if you’re on a budget. Most people who want to save money opt for sheetrock, but when you’re remodeling a bathtub, you may have to get creative since some materials– sheetrock included– don’t respond well to moisture.

You should not sheetrock behind a bathtub unless you also install some sort of moisture barrier in between the sheetrock and the framework. That is because drywall can absorb moisture, compromising the structure and potentially damaging a home’s framework long-term.

So, let’s discuss the complexities of installing sheetrock behind a bathtub. I’ll tell you about some of the best materials for the job, and I’ll also teach you how to waterproof your sheetrock so you can use it in the bathroom.

What Can You Install Behind a Bathtub?

When considering how to treat the walls of your bathtub or shower, several options exist. However, water resistance and waterproofing are essential factors to keep in mind since the walls inevitably get wet at some point.

You can install fiber cement board, glass-fiber-reinforced gypsum, or fiber mat-reinforced cementitious backer panels behind a bathtub, as long as the material is waterproof. Remember that whatever you install needs to be moisture-resistant to sustain its structure and prevent damage.

Whether you are using sheetrock or opting for another material altogether, there are some necessities for installing a bathtub wall.

Materials such as fiber cement board, glass-fiber-reinforced gypsum, and fiber mat-reinforced cementitious backer panels are all water-resistant enough to withstand even the steamiest of showers.

So, let’s see how each of these options stacks up in terms of price, accessibility, and ease of installation.

Fiber Cement Board

Fiber cement is predominantly used as siding on the exterior of a home or building because it is incredibly durable and easy to install. They are also common when installing flooring or making furniture.

You can purchase fiber cement boards at your local hardware store. The reason fiber cement board would make an ideal alternative to sheetrock is that it is virtually indestructible and water-resistant.

This product will not rot, crack or warp with time or moisture so you can have peace of mind.

There is a price difference between fiber cement board and sheetrock. While sheetrock will run between $0.40 to $0.65 per square foot, fiber cement board usually costs $0.90 to $1.05 per square foot.

Glass Fiber-Reinforced Gypsum

Glass fiber-reinforced gypsum combines the strength of resistant glass fibers and gypsum cement that is high density to make panels that are lightweight, strong, and easier to install than its traditional counterpart, plaster castings.

It is also moisture resistant. So, it will have high structural integrity, and you won’t need to worry about mold or mildew growth in the walls.

This product is durable and low-maintenance since it is easy to install. The price of the glass-fiber-reinforced gypsum panel is roughly $1.00 to $1.20 per square foot, making it the most expensive option on the list thus far.

Fiber Mat-Reinforced Cementitious Backer Panels

Fiber mat-reinforced cementitious backer panels are also gypsum panels, but they have a fiberglass mat facer and backer.

The difference is that the face of the panel has a cementitious (cement-like) coating to make it more moisture and mildew-resistant. This product has the highest rating for mold resistance.

It is lightweight, easy to install, and due to its coating, it is ideal for tile bonding. The price of the fiber mat-reinforced cementitious backer panel is comparable to the glass-fiber-reinforced gypsum at roughly $1.00 to $1.20 per square foot.

How Can I Use Sheetrock Behind a Bathtub?

If none of these options are suitable due to cost or lack of availability and sheetrock is the only option for installation, there are a few ways in which you can do this job effectively to avoid the aforementioned issues.

You can use sheetrock behind a bathtub as long as you also include a vapor barrier or waterproofing primer. Keep in mind that these options will add cost to the overall project, but they will prevent moisture from affecting the sheetrock.

Use a Vapor Barrier

Vapor barriers or vapor retarders come in various classes based on permeability.

A vapor barrier is simply a material you can add to the sheetrock that reduces the rate and amount of water vapor that can move through it. Examples of this are sheet metal, rubber membrane, or polyethylene sheets.

For the lowest level of permeability, the options are products like cellulose insulation, board lumber, concrete block, and so on. As the possibilities of materials differ, so may the price of products.

Use a Waterproofing Primer

This method will allow you to use the sheetrock without adding a second layer of protection to the installation. All you need to do is coat the sheetrock with water-resistant primer.

Fortunately, the process of adding the primer is so simple. It does not require the assistance of a professional, and you can do it yourself in one afternoon.

You can find these waterproofing primers at any paint manufacturer, as well as the supplies needed to coat the sheetrock properly. Using a primer is a more cost-effective approach than purchasing pretreated sheetrock.

Opt for Pretreated Sheetrock

The terms drywall and sheetrock are often used interchangeably, as sheetrock is simply a type or brand of drywall.

If using a waterproofing primer is an added step that would be too time-consuming, then you may want to look for pretreated drywall at your local hardware store.

Though the term is outdated, Greenboard is the proper term to refer to water-resistant drywall. Though Greenboard is still common in shops, most people prefer paperless or moisture-resistant paper drywall.

Conclusion

Whatever you choose to install behind your bathtub, the most crucial factor is ensuring that water does not penetrate the structure and cause mold or mildew and eventual damage to the framework.

Though some options may be more costly than others, they may prove to be the most cost-effective in the long run.