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How to Build a Shower Pan on Concrete Slab
If you’re remodeling your bathrooms and want to know how to build a shower pan on concrete slab or plywood floor, this article is for you. I’m going to walk you through the costs, the materials to use, and the essential steps required for building a shower pan on a concrete floor or plywood sub-floor.
If you’re planning to tile your shower, the first thing on your list should be to build a shower pan. But before you do that, start by preparing and waterproofing the subfloor. If you’re building your shower pan on concrete, consider getting some help from a pro, or at the very least make sure that your measurements are precise. And while putting up a curb is optional, doing it correctly will ensure that you won’t have standing water in your shower and more importantly prevent mold from growing androind app development . If this is something you can handle by yourself, here is how to build a shower pan on concrete slab:
To build a shower pan on concrete, you’ll need to first create a subfloor by pouring a layer of cement over the existing slab. The cement should be about 1/2 inch thick, and it should completely cover the old slab.
Once this is done, you can add the actual shower pan by placing a cement board over the cement subfloor. The cement board should be laid directly on top of the old concrete slab and nailed into place with galvanized roofing nails. Finally, use waterproofing caulking between all joints in order to ensure that water doesn’t seep into the structure of your shower pan.
One important thing to keep in mind when building a shower pan on concrete is that you must do so before tiling any part of your shower floor or wall with tile. If there’s no cement board underneath your tiles, they will simply fall off as soon as water comes in contact with them.
| Step | Description | Advantages | Disadvantages |
|---|---|---|---|
Pour Concrete First | Process:1. Pour the concrete on the slab. 2. Allow the concrete to cure. 3. Install a plywood floor on top of the concrete. |
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Install Plywood First | Process:1. Lay down the plywood on the concrete slab. 2. Secure the plywood to prevent movement. 3. Pour concrete into the seams around the plywood. |
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Waterproofing | Process:1. Use cement board as a moisture barrier. 2. Ensure proper coverage on the shower floor. |
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If you have access to a power saw and miter box, use it to cut the cement board into pieces that will fit around the drain and toilet flange (if you have one). Use adhesive such as Liquid Nails or construction adhesive to glue down the pieces of cement board.
Now you’re ready to start building your shower pan! Start by spreading a layer of thinset mortar on top of the cement boards and then place your first piece of plywood on top of it. Make sure that the plywood is level with each side of the walls and that it is flush against all four walls so there are no gaps between it and the wall.
Once you have made sure that everything is level and flush, apply more mortar underneath each piece of plywood until it’s completely covered in thinset mortar. You should use at least 1″ of thinset mortar underneath each piece of plywood so there won’t be any gaps between the pieces when they are stacked together later on in this step-by-step guide for how to build a shower
Step 1: Install backer board
If you are building a shower pan on a concrete slab, the first step is to install waterproofing on the floor. Use cement backer board to protect your concrete from water damage and mold. To learn more about how to install cement backer board for showers, read our guide here.
Step 2: Cut and place drain
Cut the drain hole in your shower pan and place it over the drain opening using silicone. Make sure the drain opening is centered so that your pan will sit flat on top of it when you are done installing it.
Step 3: Install shower pan liner
Place a layer of foam tape around the perimeter of your shower pan liner to ensure a tight fit against your walls when you set it in place. Then put down another layer of foam tape along the bottom edge of the liner before setting it into place over your drain opening.
Step 4: Set shower base in place
Set your shower base into position on top of your backer board and make sure all seams line up flush with one another before securing them together with silicone caulk or other sealant product like caulking gun sealant or caulking compound caulk (for example).
A shower pan is a waterproof base for your shower. It helps to keep water from leaking through the floor and protects your subfloor from damage. The shower pan is made out of waterproof material that can be made of plastic, ceramic or metal.
The shape and size of your shower pan will depend on your needs, but it’s important to make sure that it fits correctly so that you don’t have any leaks. To install a new shower pan, you’ll need to lay out the dimensions on a flat surface, then cut out the holes for plumbing fixtures. Once this is done, you can install the pan by fastening it to the subfloor with screws or nails through predrilled holes.
Shower pans are the waterproof foundation for shower stalls. Shower pans are made of fiberglass or plastic and are installed on a platform of wood, stone or concrete. The shower pan is designed to be waterproof but not leak-proof. The shower pan usually has an overflow hole in case of a clog.
🧱 How It Works
You create a sloped mortar base (“pre-slope”) atop plywood, layer a waterproof membrane, then add a finish mortar bed and tile. This prevents leaks and ensures water flows toward the drain.
📋 Materials & Tools Required
- Plywood subfloor: Clean, in good condition
- Mortar mix (dry-pack): For pre-slope and finish layer
- Waterproof membrane: Sheet or liquid, e.g., Schluter Kerdi or RedGard
- Cement backer board (optional walls)
- Drain assembly, thin-set, tile, grout, trowels, level, float, mixer
⚙️ Step-by-Step Instructions
- Prepare Subfloor & Drain
- Ensure plywood is stable and sloped approx. ¼″ per foot toward the drain hole.
- Cut drain hole and install drain flange per manufacturer instructions .
- Create Mortar Pre-Slope
- Lay roofing felt or tar paper on plywood.
- Build edge perimeter at correct height.
- Fill interior with dry-pack mortar (sand mix) and compact to form slope to drain. Cure 24 hrs.
- Apply Waterproof Membrane
- Sheet membrane: press into slope, extend 6–8″ up walls, seal corners/fold, cut X at drain.
- Or apply liquid membrane with fiberglass in corners.
- Add Finish Mortar Bed
- Mix mortar to smooth consistency.
- Screed a final sloped layer about 1″ thick, tapering to drain. Let cure.
- Install Tile
- Set tile with thin-set mortar.
- Grout and seal joints per your grout’s waterproof rating.
- Caulk transition between tile floor and shower curb for movement control.
- Install Wall Backer (if tiled)
- On walls above pan, fit cement backer board with thin-set under mounting screws.
- Apply membrane to wall/pan interface before tiling.
⚠️ Common Pitfalls & Tips
- Under-slope leads to pooling—maintain ¼″ per foot .
- Skipping membrane risks leaks—tile and mortar are porous .
- Seal drain properly—failures often occur around drain.
- Cement board vs plywood: Cement board is optional for floors; plywood is fine if properly waterproofed.
✅ Quick Facts
- Pre-slope mortar bed cures for 24 hrs before membrane.
- Membrane must extend up wall at least 6–8″.
- Second mortar layer should be smooth and properly sloped.
- Tile joints need waterproof grout; use caulk at terminations.
How to Build a Shower Pan on Plywood Floor
A shower pan is the structure that supports your tile shower. It keeps the water from seeping through the floor, and it gives you a level surface for tiling. You can build a shower pan yourself by following these steps:
1. Lay out the floor joists in the shower area with chalk lines and then cut them down to size with a circular saw.
2. Screw 2-by-4s to each joist at 16 inches on center using galvanized deck screws (Photo 1). You’ll need one screw per joist end, so use two screws per joist end where possible; otherwise, stagger your screw locations on adjacent joints (Photo 2). To ensure even spacing between joists, measure from the outside edges of adjacent joists and mark along each 2×4 with a framing square before drilling holes for screws.
3. Use nails to secure 2×4 blocking between opposite rafters in the ceiling so that it spans the width of your shower (Photo 3). Make sure you nail into the floor joists below so that there’s no chance of sagging over time due to wetness or weight from tiles or fixtures hanging from
A shower pan is a waterproof membrane that rests on top of the subfloor. It’s important to install it properly so that water doesn’t seep into your basement. If you’re building a shower on a concrete slab, here are the steps for installing a shower pan on plywood flooring.
1 Set up sawhorses and lay out your sheets of plywood. Use them as a guide to cut out the pan panels, using a circular saw with a carbide blade.
2 Fasten the panels together with countersunk deck screws placed every 16 inches along each seam. Apply construction adhesive between each seam before nailing down the panels with 2-inch nails or deck screws.
3 Cut out holes for plumbing and electrical lines in the center panel before fastening it to the outer ones with more adhesive and screws.
4 Cut an access door in one corner using a jigsaw or keyhole saw and attach hinges and strike plate by drilling pilot holes and driving screws through them into the plywood paneling.
How to Tile a Shower Floor on Concrete
Tiling a shower floor is no different than tiling any other floor. However, the challenge is in making sure that the tiles are level and flat. If they’re not, they’ll look terrible and you’ll end up having to redo them. This can be frustrating and expensive if you don’t know what you’re doing. Here’s how to make sure your shower floor is level and flat so that your tiles look great!
Step 1: Prepare Your Concrete Floor
If you haven’t already done so, prepare your concrete floor by removing any loose or damaged concrete. It should be clean and smooth before proceeding with this project. You can do this yourself or hire someone to do it for you.
Step 2: Measure Out the Pans for Each Wall
Measure out where each wall will go using chalk lines or level tape. Make sure that each line is level from corner to corner and from edge to edge on both sides of the pan (i.e., not just one side). Measurements should only be taken from one side at a time so as not to interfere with measurements taken on other walls later in the process. Once measurements have been taken for all four walls, use them as guidelines
How to Tile a Shower Floor on Concrete
Installing a tile shower floor is one of the most challenging jobs in tile installation. The biggest challenge is that you need to make sure that the waterproofing membrane is completely flat and level. If your floor isn’t flat, it can cause problems with the grout lines in the future. This article will show you how to install a tile shower floor using a mortar bed.
Step 1 – Lay Out Your Floor
Before you start laying tiles, make sure that your subfloor is level and plumb (square). You should also check for any major defects in your concrete slab, like cracks or weak spots. These problems can be fixed with a reinforcing steel grid system that’s covered with cement grout (or epoxy).
Step 2 – Prepare Your Subfloor
The next step is preparing your subfloor by nailing down 1/2-inch plywood sheets onto the concrete surface using 15/8-inch galvanized roofing nails. Place these sheets about every 10 feet across so you’ll have plenty of room for tiling later on. You’ll want around 12 inches between each sheet so there’s room for mortar when installing tiles on top of them later on.
In summary:
Building a shower pan on plywood involves creating a two-layer mortar slope, installing a reliable waterproof membrane, and finishing with tile. This method ensures durability, proper drainage, and long-term waterproofing.