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How To Build A Shower Pan On A Concrete Floor

A shower assembly is not complete without a shower pan. If you have a concrete floor, it is possible to place the shower pan over it. You should plan carefully before you do this project. In this post, we will teach you how to build a shower pan on a concrete bathroom floor based on our research.

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To install a shower pan over a concert floor, the steps involved are the following:

  1. Prepare the subflooring surface.
  2. Install the shower drain flanges and prepare the shims.
  3. Add the mortar mix as a base. 
  4. Place the shower pan on the surface.

You have the option to use a prefab or a customized shower pan. Regardless of your choice, you should follow the correct process of installing the shower pan to avoid drainage and damage to the concrete floor. Read further to learn about how to add the shower pan, project costs, and more.

photo of a wooden-white-bathroom-two-sinks-towels, How To Build A Shower Pan On A Concrete Floor

Installing A Shower Pan On A Concrete Floor

A shower pan is necessary if you have a shower in your bathroom. It adds to the aesthetics and functionality of the space. You should install a shower pan to protect the floor where you are standing in the shower.

Without the pan, there will be no proper water drainage. In that case, mold and mildew can accumulate. Also, the concrete floor can crack. The concrete surface will not be able to sustain the water pressure.  

photo of a shower-drain-box-grate-on-base

Before you start, you should consider the following:

  • Measure the space where you plan to shower. Account for your body size when measuring.
  • Select the right size of your shower door. Consider its location when accounting for the total shower space.

Choose if you want to build a shower pan from scratch or purchase a prefab one. Below are the processes for each option. 

How To Build A Shower Pan On Concrete Bathroom Floor?

Creating a shower pan from scratch will take time, but you can customize it to match your needs. You need to gather the following materials for this project:

  • 2 bags of premixed cement and sand
  • Thin-set
  • Lumber board
  • Tiles (bullnose, mosaic tile)
  • Grout
  • Tile caulking chalk that matches grout color
  • Liquid waterproofing barrier
  • 4-inch screws
  • 1-inch nails
  • Hammer
  • Chop saw
  • Level
  • Margin trowel
  • Small foam roller

Here are the steps to follow:

  1. First, build the shower curb to create a sloped waterproof floor. Assemble the wooden frame and fill it with the concrete mix. Take into account the measurements for the door and drainage.
  2. Wait at least 24 hours for the concrete to dry before removing the frame. Sand the curb to level it.
  3. Next, prepare the surface where you will place the shower. With a drywall knife, scrape burrs and imperfections on the surface. 
  4. Pour the mixed sand and cement into the area. Use the trowel to remove air bubbles. Wait for at least three days to cure. 
  5. Apply the waterproofing on the perimeters and the whole pan. 
  6. Once the waterproofing dries, dry lay the tiles.
  7. With the thinset, place the tiles carefully on the surface. Do not puncture the surface with waterproofing. 
  8. Caulk the tiles on all the corners and the curb. 
  9. Add the grout and seal. 

Achieving the desired shower pan will take a few days, but it will be worth it.

How Do You Install A Prefab Shower Pan On A Concrete Floor?

In contrast to a custom-built pan, a prefab shower pans minimizes the time and effort of installation. Depending on your needs, you can choose materials like acrylic, custom tile, composite, or fiberglass.

photo of a porcelain-shower-base-bathroom-horizontal

Follow the procedure below:

  1. Purchase the shower pan. Check if all the parts are complete.
  2. Prepare the subfloor. Smooth any lumps and bumps on the concrete surface. 
  3. Mark the locations of the shower pan feet. If there are none, create a base with sand and mortar.
  4. With the shims on the floor, use these to create a level space for the pan. 
  5. Try fitting the shower pan in the desired area. Check if there is a need to move the drain pipes and the level space.
  6. Adjust the shims to level the pan. After getting the correct alignments, pre-drill the shims on the subfloor.
  7. Mark the flanges on the studs as your reference in the final installation. 
  8. Get the shower pan flange and add a bead of the plumber's putty or silicone under the rim of the drain flange. Place the flange through the shower pan from the top.
  9. Place the foam or rubber gasket on the underside of the shower pan.
  10. Add the paper gasket on the drain flange threads. Place and tighten nuts on the flange threads. 
  11. Connect the shower pan to the flanges.
  12. Then connect the flanges to the studs with the built-in clips, if there are any. You can drill the flanges on the studs if there are no clips.
  13. Afterward, complete the shower drain assembly. 

If you're doing the project yourself, refer to the product manuals. Otherwise, you can ask a professional to do the job.

How To Select The Right Shower Pan To Install?

Your needs and preferences will determine what shower pan you install. Here are some things to consider:

photo of a white-corner-shower-base-old-bathroom

  • Visuals: You can match the shower pan to the shower walls for a cohesive look. You can choose something eccentric if you want to show off your style.
  • Mobility restrictions: Assess how you and your family members will use the shower. You can install a curbless shower pan if tripping is a concern.
  • Cost: Consider your expenses for installing or purchasing a shower pan. The benefits of the shower pan should outweigh the cost and not the other way around.

How Much Does It Cost To Install A Shower Pan?

Knowing that setting up the shower pan can be tedious and time-consuming, you might want to hire someone to do the job. 

It will cost you around $500-1,550 to install a prefab shower pan, while building it costs between $900-3,500. The labor costs are a big chunk of the amount. The more complex your requirement is, the more fees you incur.

Check out this post: How Much Does A Shower Pan Cost To Buy And Install?

What Kind Of Concrete Mix To Use For A Shower Pan?

If you are building a shower pan, you should find a suitable concrete mix. For shower pans, you can use a basic mortar mix made of sand and Portland cement.

The mixture creates a solid, water-resistant barrier. To create the concrete mix, here are the ingredients:

  • Portland cement (1 part)
  • Fine sand (4-6 parts)
  • Water 

Place the ingredients in a concrete mixer. Mix until you get a clay-like consistency. The mix should hold its shape and release water when squeezed.

If you are not going to mix the concrete yourself, you can buy ready-mixed commercial concrete. A popular choice is Quikrete.

Click here to see this product.

Whatever concrete mix you choose, you should apply it properly when installing a shower pan.

Should You Pre-Slope A Shower Pan?

Pre-sloping is a must, whether you build or buy a prefab shower pan. You should establish the slope before adding the pan.

The pre-slope is vital in water and moisture management of the shower assembly. The slope prevents water from pooling in the shower area by directing water to the drainage.

If the water flows to the mortar bed under the shower tiles, it can damage the surface, and mildew will accumulate.

The shower pan requires at least a 4% slope or 1/4-inch per 12 inches. To get the slope, use a leveler on the top edge of the shower pan. 

Afterward, use mortar mix to create the slope. The mortar should be strong enough to support the weight of the shower assembly while resisting water intrusion.

The thickness of the mortar slope is between 1/2-1 inch. Wait 24 hours for it to dry.

In Summary

photo of a wooden-white-bathroom-two-sinks-towels

You can build a shower pan from scratch or purchase a prefab one. The process of installing the shower pans will vary due to the time and effort involved.

Creating the shower pan on your own will take longer. If you choose a prefab shower pan, you should refer to the product manual for detailed instructions.

Either way, you should use a suitable mortar mix to support the shower pan. It is also important to establish the pre-slope to facilitate the water drainage of the shower unit. 

The shower pan is an important part of the shower. Preparing it well adds to the design and usability of your bathroom.

Read more about showers from our posts:

How High Should Rain Shower Head Be?

Gap Between Shower Door Frame And Wall—What To Do?