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Felt Pad for Shower Base: What It Is and Why It Matters

One of the top problems for homes in the United States is poor plumbing practices. When contractors do not install pipes and water fixtures properly, water can leak and cause structural damage to your home. 

It can also lead to issues with mold and mildew, creating a health hazard. 

One of the ways to prevent this is with proper installation practices. Using the felt pad for shower base is one of the ways to stay safe and protect your home from water damage in the future. Let’s look at what the felt pad does for your shower and how to install it. 

Felt Pad for Shower Base

What Is the Felt Pad for a Shower Base?

A felt pad for your shower base is a section of felt cloth put under the shower base during installation. The felt pad helps keep the shower base in place once installed by increasing the contact between the shower and the floor. 

Most shower bases include a felt pad as part of their packaging. These felt pads are fitted for the shower base, helping contractors and DIY builders to install their shower without getting a mismatched cloth. 

Also, many of these felt pads receive treatment to help with waterproofing. 

What Does the Felt Pad Do?

Since most showers don’t have a flush underside of the base, the felt pad increases the friction of the parts of the shower that touch the floor. 

The felt doesn’t slip as much on the floor, meaning your shower base is more stable with the pad underneath. 

Felt isn’t the only material you can use under a shower base. Felt pads simply tend to be the cheapest and easiest option to use. 

When Would You Install a Felt Pad?

Felt pads go underneath the shower base, meaning they need to go down before you place and set the shower base. 

The main thing to remember about using a felt pad is that they require the flooring to be level first. Most professional contractors recommend mortar cement or spray foam for uneven flooring over a felt pad. 

Also, softer shower bases might not benefit from using a felt pad. These pads don’t offer the structural reinforcement that other options can provide, causing the shower base to flex when someone stands on it. 

Mortar vs. Felt Pad

The other common choice for stabilizing a shower base is mortar cement. Mortar refers to a blend of sand and cement meant to help fill gaps between two things glued together with the mortar cement. As the mortar dries, it sets into a solid. This change causes the mortar to hold items in place and provide a semi-waterproof seal. 

When used under a shower base, mortar fills in these cracks and rigidity to the shower base when it hardens. 


Mortar can also be used to help even out the flooring, ensuring the shower connects to the drain. 

How to Install a Felt Pad for a Shower

You won’t need to install the felt pad for your shower until the shower site is ready for the base. So, you should have the flooring foundation, support structures, and insulation for the shower walls built before installing the felt pad. 

With all of the support structures set, you’ll want to follow these steps to install your shower base: 

  1. Measure the level of the installed flooring to ensure that the area will be level. 
  2. If the flooring is not level, apply mortar cement and decide if you still want to use the felt pad. 
  3. While the mortar cement is still wet, place the felt pad down so that the pad doesn’t cover the drain pipe for the shower. 
  4. Place the shower base on top of the felt pad, once again lining up the drain hole with the drain pipe for the shower.
  5. If you use mortar cement, wait for it to set before standing on or shifting the shower base from its position. 

From there, you can begin with waterproofing the shower base. Mostly, this process comes down to filling any holes between the shower base and the flooring with grout. Any grout or mortar used during this step will need to dry before you can move on to the next step. 

Waterproofing Your Shower Base

In addition to adding structure to your shower, a felt pad also helps a little with waterproofing your shower. The felt pad can act as a barrier against any water that leaks through cracks in the shower base, preventing water damage to the flooring or wood underneath the shower. 

However, there’s more to waterproofing your shower than just the felt pad. Though the plastic or ceramic material of the shower base is waterproof, any grout used in the shower isn’t. Grout is porous, meaning that water can travel from the shower and through the grout. 

Without a protective layer, this water will damage wood, nails, and other support structures in the wall over time. 

Most showers use an interior membrane of some kind behind the grout and tile. These membranes create a watertight seal that won’t allow shower water to go past them. This cause the water to evaporate over time without collecting in wood and damaging it. 

Protective Layer

These membranes come in both sheet and liquid forms. Both forms go into the wall before the tile and grout do. Sheet membranes use adhesive to stick the solid membrane onto the wall, while liquid membranes go on with paint rollers and dry into an elastomer film. 

Foam wallboards can go up in place of these membranes, as well. These wallboards use waterproof foam to block water from entering through the grout. 

Each of these waterproofing options will need to line up with your shower base. So, ensure that you think about how you will waterproof before setting up the base. 


Here are answers to some of the common questions out there about setting up your felt pad for shower base:

What do you put under a shower base?

The most common options to put under a shower base are a felt pad and mortar cement. Both of these offer anti-slip properties to the underside of the shower and prevent water from leaking inside the shower base. Mortar offers more support to the base, while the felt pad is easier to install. 

Do I need tar paper under the shower base?

Tar paper helps absorb moisture that can get into the subfloor when mixing mortar for the shower pan. Most shower installations use tar paper for the shower pan since this is where water will fill in while the shower is in use. 

Can I use spray foam with a felt pad under a shower base?

Spray foam helps reduce the flex of the shower base by filling in the space between the shower base and the flooring. You can use both spray foam and the felt pad underneath the shower base, but it isn’t a requirement for all types of shower bases or spray foam to include the pad. 


The felt pad that comes with your shower base is crucial to helping your shower stay in place after installation. The felt cloth increases the friction between the floor and shower, helping to keep everything in place even when the water is flowing. 

Felt pads aren’t required, or even recommended, for every shower setup. That fact is why, unless you know what to do, consulting a contractor for your bathroom before installing a shower is important.

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