gap between backer board and shower pan

How Much Space Should Gap Between Backer Board and Shower Pan Be

Proper installation of bathroom components is crucial since it influences their functionality, lifespan, and overall functioning of your bathroom. With that in mind, should you leave a gap between backer board and shower pan?

You should leave 1/16 inch space between the backer board and the shower pan and fill this area with caulk. This gap will ensure your bathroom tiles do not crack.

Making sure this gap exists is important, considering its importance. This post offers a step-by-step guide to installing a backer board in your shower and utilizing the gap between the backer board and the shower pan. It also covers how to choose the best backer board.

How Much Should the Gap Between Backer Board and Shower Pan Be

There are different reasons for leaving a gap between the backer board and the shower pan, some of which include the following:

  • It marks the spot to lay the first row of tiles.
  • Maintaining the 1/16-inch gap around the edge of the shower pan will keep the tiles from cracking. 
  • The gap gives room for the shower pan to expand in case of increased temperatures.

What To Do With The Gap Between Backer Board And Shower Pan?

Caulk is the go-to option when filling the gap between the backer board and the shower pan. Homeowners prefer caulk over grout because of its flexibility. 

Given the ability of the shower pan and tiles to expand, you need something flexible to minimize cracking. Besides flexibility, caulk boasts better waterproofing characteristics than other materials, such as grout. 

However, you should replace the caulk every five years or after a mold and mildew infestation. Remember, caulk is not flawless; it dries and shrinks with time, a problem that limits its waterproofing qualities. 

Some households use grout to seal the gap between the backer board and the shower pan. Grout has decent water-resistance properties, but it is not waterproof enough. 

In addition, grout is rigid (unlike caulk); it’s susceptible to cracking. Its rigidity, however, makes it ideal for hard-level surfaces. 

How Soon Can You Caulk After Grouting Between Backer Board And Shower Pan?

There’s no harm in combining caulk and grout, only that you need to allow grout to cure first. It can take 24-72 hours, and you can test its dryness by sprinkling water on it. 

Wet grout is porous and absorbs all water sprinkled on it. Apply caulk after water rolls off the grout surface. 

Does Backer Board Go Over Shower Pan Lip?

Home improvement experts don’t fancy the idea of the cement board going over the shower pan lip; instead, they recommend leaving a 0.6-inch gap between the shower pan lip and the backer board. Doing that will preserve the structural integrity of your bathroom. 

Why Use Cement Boards With Shower Pans?

Home improvement professionals recommend cement boards because:

1. They Are Cheap

Spending less money without sacrificing quality and longevity cannot be overlooked. Cement boards are inexpensive compared to other backer boards, which cost a fortune. 

2. Durability

Cement boards promise durability once installed. They outlast their counterparts and can withstand deterioration caused by continuous abrasions. 

3. Easy To Clean

Cement boards mount incredible resistance against stains. Even if they get dirty, you only need a wet sponge or cloth to clean the soap residue and water droplets. 

4. They Look Stylish

Your bathroom design conveys a right or wrong message to individuals walking in and out of the room. The cement board will help enhance the aesthetic appeal of your bathroom, something that other backer boards won’t match. 

Furthermore, they look contemporary and are resistant to fading. 

Factors To Consider When Choosing a Backer Board For Your Shower

Besides knowing the recommended gap between the backer board and your shower pan, it’s good to know what to take into account when shopping for the former. The following three factors will help you make an ideal purchase and installation:

1. Budget

The cost of a backer board depends on the size and type of the fixture. A square foot of cement board will cost you between $4.33 and $6.90. 

2. Functionality

Making the best-informed decision about buying and installing backer boards rests on their functional aspects. For instance, some homeowners will incorporate waterproof sealers, while others will consider additional insulation. 

3. Design

Backer boards come in different designs, such as recycled, textured, and wood-look varieties. They are also available in multiple materials, including smooth and rough-sanded surfaces. 

Furthermore, the glass and the natural stone look are examples of finishes you’ll come across in the market. 

See also Tile Redi Shower Pan reviews

How To Install A Backer Board In Shower

Having established that you should leave a gap between the backer board and your shower pan, it’s good to know how to install them. Before starting the installation, it’s good to note that the board can be too heavy for you, so have someone help you place it. 

Follow the steps below to install a backer board in your shower:

  • Estimate the area where you would like to place the backer board, marking out its perimeter with a pencil. Using a level will improve the accuracy of the installation. 
  • Use a saw blade or utility knife to remove excess wall material. 
  • Keep the walls at the backside of the backer board moisture-free by employing plastic sheeting on the wall studs. Additionally, cover the shower lip of the pan with the edge of the sheeting. 
  • Use a handsaw or electric jigsaw to cut out the required piece of the cement board, then clean the cuts. Backer boards usually measure 3’ x 5’, so cutting out the excess part is necessary. 
  • Insert zinc-plated screws and add adhesives. 
  • Trim the cement board to conform to your fixtures. 
  • Mount the cement board on wall studs and drill holes through the board and the studs using a 4” grinder. Ensure the holes are equidistant. 
  • Insert a screw on each hole, and be careful not to over-tighten. 
  • Finally, caulk the spot and seal it with drywall tape. 

See also Schulter shower system problems

FAQs on Gap Between Backer Board And Shower Pan

1. How Far Off Shower Pan Should Cement Board Be?

Experts advise you to install the board 1/8 inch above your shower pan. 

2. Should There Be A Gap Between Shower Pan And Wall?

You must leave a space of 1/16 inch between the shower pan and the tile and fill the gap with caulk. It will serve as a waterproofing material. 

Besides that, you should know areas where grout is ideal and spots where caulk would be more suitable. 

3. Can You Put Tile Directly On Backer Board?

You can install ceramic tiles directly over the backer board to lengthen its lifespan. Since it doesn’t harbor organic materials (unlike plywood), it curbs rot and the growth of mold caused by continuous exposure to moisture. 

4. Can I Use Plywood With A Shower Pan Instead Of a Cement Board?

Several modern bathrooms have cement boards as opposed to plywood. Experts argue that plywood is porous and not sticky enough, making it unsuitable for use with thinset mortars that incorporate latex. 

Final Remarks 

In summary, leave a 1/16-inch gap between your shower pan and the backer board. This space is essential because it gives the shower tray room to expand, thus protecting tiles from avoidable cracks. 

The gap also shows you where to place the first tile. In addition, you can fill the gap with caulk or grout (though caulk is the better option) because of their water-resistance properties. 

See also Kbrs shower pan problems

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