Should You Insulate Interior Shower Walls? [And How To]

There are many forms of remodeling and home renovations. One of the more popular ones is a bathroom-re-do. It is always nice to have a little more space, better lighting, and some new porcelain. You might also be considering whether or not you should insulate interior shower walls? We've researched this to determining if shower wall insulation is essential for your bathroom.

You should insulate interior shower walls. It will help with heating and cooling, noise reduction, and, most importantly, moisture control.  It is critical to have the least amount of moisture for your health and your home's well-being.

This article will discuss the benefits of insulating interior shower walls. We will also cover the importance of controlling moisture and how different types of insulation are better for this job than others. Later, we will go through how to insulate interior shower walls. 

Small bathroom interior with sink and glass door shower with concrete textured walls and floor - Should You Insulate Interior Shower Walls [And How To]

About Insulation

Modern black linear drain in a bathroom lined with ceramic tiles imitating wood.

You might be wondering what the purpose of insulation is. Installing insulation is beneficial for temperature control in your home. It also has the added benefit of suppressing sound between rooms. Preventing mold and rot is another purpose of insulation.

Insulation comes in many different forms with variations in material, the application process, price, and eco-friendliness.

Fiberglass insulation is the most commonly used type of insulation. As the name implies, it is made of fiberglass particles. Fiberglass insulation can be found in rolls, batts, and loose-fill forms. Typically fiberglass insulation is less expensive, making it budget-friendly. 

Insulation better improves your space. It also serves as an energy saver because you can trap heat inside; it won't escape with the blanket of insulation around your house. Also, if you are trying to cool your house down, the cool air coming from your air conditioner won't escape, and your rooms will stay nice and cool.

What Do You Put Behind Shower Walls?

Small bathroom interior with sink and glass door shower with concrete textured walls and floor.

It is important to have a few things behind your shower walls. First, you have to have a moisture barrier. Second, you have to have insulation. Both of these combined will make for a proper and safely complete bathroom.

A moisture barrier is critical. It's pretty self-explanatory as its job is in its name. Regardless of the type of shower you have, it will produce moisture. It is not good to have moisture in your walls because it can cause mold growth and wall rot. This is why you should have a moisture barrier underneath your shower pan and behind your shower walls. 

You should have concrete behind shower walls, especially if you have tile. Concrete or cement is very porous, allowing water to pass through. However, the best thing about concrete is it will never retain water, so you don't have to worry about rotting concrete.

Insulation is also necessary behind shower walls. Pick out the type of insulation that will do best at fighting the retention of moisture. The goal is to not have mold and bacteria growth. Foam insulation is a great option for behind shower walls. 

Should You Put Plastic Behind Shower Walls?

Bathroom demolished all to the concrete basement wall

In some cases, it is smart to cover the studs in your walls with plastic. This plastic will help protect your studs from water, thus reducing the risk of them molding or rotting. It would be best to choose a 6-millimeter thickness of polyethylene to cover your studs. 

There is a catch, however. It is still possible for things behind the plastic to still get wet. The moisture and condensation from the shower can sneak past the borders of the plastic covers. It is important to make sure you have the right size to cover from top to bottom.

It is not wise for the plastic sheets that cover your studs to be the only protection from water damage. This should be an additional measure of protection along with water-resistant insulation.

Can You Use Plywood Behind Shower Walls?

Bathroom demolished all to the concrete basement wall

It is not a good idea at all to use plywood behind your shower walls. Plywood in no way can protect the wall interior from water and water damage. 

What will happen is the water from the shower and the condensation from the steam will seep into the plywood. The plywood would never fully dry out and continue to collect moisture. Eventually, the plywood would grow mold and other bacteria. It could also rot and break down, providing no barrier from moisture. 

The point of putting something behind your shower walls is to protect the studs and other materials from water. Plywood is not protective. It actually can cause more harm. Once it creates mold, you are at risk of breathing in the mold and that could lead to serious health problems. 

It is not healthy to have mold in your home. Let alone inside your walls. This will lead to future problems as it spreads and causes more damage.

Can You Waterproof Drywall For A Shower?

It is possible to waterproof drywall. You can do this behind your shower. However, it is not a protection style we would recommend. 

If you plan to install a shower, you can waterproof the existing drywall with a clear water-based urethane. This product can be found at your local home improvement store. 

It is highly recommended to coat the entire sheet of drywall from top to bottom. Be certain that you focus on the edges to seal the job. It will take you a few coats to ensure the drywall is protected as much as possible. 

If you insist on using drywall behind the shower, you should make sure that you select drywall that is specifically made for wet areas. This will help with protection but not guarantee it. There are types of drywall that are moisture-resistant, but none that are water-resistant.

Although it is possible, it is not a method that we would recommend. You are at risk for damage, mold, and re-doing your bathroom walls shortly. We do, however, have a method of protection that we do recommend.

Considerations for How To Insulate Interior Shower Walls

Walls and floor thermal insulation in bathroom interio

How you insulate interior shower walls is dependent on a few things. For one, budget is a big factor. You should consider all your options to have something that works for you and doesn't break the bank. Different insulation types can range from $1 a square foot to $6 a square foot.


Location is also a factor. If your bathroom is on the wall that is shared with the outside of your house, you will need a higher level of protection. Outside elements are a lot tougher than the temperature range inside your home.

Since we are talking specifically about an interior shower, outside elements are not relevant. With interior showers, you will want to insulate for different reasons, like preventing moisture collection and better indoor temperature control.

Noise reduction is also an added benefit of insulating your bathroom. The insulation plays as a noise barrier keeping your bathroom private and comfortable.

Insulation R-value

Make sure you have a high R-value. This is a form of organizing insulation by strength. The higher the R-value, the better the quality. Also, be sure to properly install moisture barriers. These should be underneath your shower and on the wall of your shower. 

We would also recommend covering your studs with polyethylene plastic sheets for extra protection for your studs. This is in addition to insulation and moisture barriers. However, it is at your discretion whether this is necessary or not. Sometimes it is not necessary depending on the build of your bathroom. 

Insulation Type

Although a bit more costly, sprayed insulation is often the best version of protection, especially if it is foam. This foam insulation is water-resistant, which makes it perfect for behind the shower.

We would recommend eco-friendly foam insulation, as well. This foam is soy-based which is beneficial because it is resistant to mold and mildew. This option is also beneficial for reducing your carbon footprint not only because of the material but because it will reduce the energy you spend, heating and cooling your home.

Final Thoughts

Modern, gray bathroom with walk in shower, mirror and countertop basin

Although it may be more money and more work, properly installing insulation for your interior bathroom is completely necessary. It can save you from future headaches that you are pretty much asking for by foregoing these steps. 

In this article, we covered what insulation is as well as its purpose. We also discussed different methods of insulation. With this knowledge, we are better equipped to make decisions for our bathroom construction.

Protecting your home and yourself from water damage and other negative effects of running water in the home are critical. Additionally, insulating your bathroom will help in other areas as well, including finances. Better insulating your home takes some weight off of your energy bill from playing consistent catch-up with the elements outside. 

And hey, it is always good to call a professional to take a look at your situation. Every home is unique, and so is every bathroom. This will help you determine which direction of the insulation process is best for you.

For more articles like this one, please visit:

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