What Size Should A Shower Curb Be? (Minimum Curb Height)

When building or renovating a bathroom, you must install some sort of curb or rim at the bottom to catch any excess water. Right now, you may be wondering to yourself just how tall a shower curb should be?

The standard shower curb height in the United States is a minimum of 2 inches above the top of the drain. The recommended minimum width of a shower curb is 36 inches or it can be 42 to 48 inches wide.

This is building code however it does not mean that the curb itself must be 2 inches high. It means that you must have 2 inches of a drop from where the drain is located to where you step in.

Now that you know the correct size of a shower curb, let us explore this topic further and in more detail below. We will discuss what exactly a shower curb is, why it is necessary, and how to make one properly. I will also explain how to create a curbless shower and where to purchase a pre-made shower curb.

So, if you are ready to learn more, then please continue reading…

* This article may contain affiliate links. As an Amazon Associate, I earn from qualifying purchases. 

What is a Shower Curb?

A shower curb keeps water contained in the shower area, preventing it from leaking onto the bathroom floor. It is essentially the border between the base of the shower pan and the bathroom floor. It can also be referred to as a shower threshold or a shower dam.

Shower curbs can be built or bought. The form is usually made of wood or concrete, but it can also be fabricated out of rubber.

Shower curbs are the first line of defense against water damage and should be crafted or installed according to building code regulations.

What is the Purpose of a Shower Curb?

The purpose of the shower curb is to keep water in the shower area only. It can also act as a foundation for mounting brackets for a shower door.

Should the unthinkable happen and a water pipe gets backed-up or the drain gets clogged, the shower curb acts as a fail-safe until the problem can be properly fixed.

While the minimum curb height is 2 inches, that does not mean that curb itself must be 2 inches high.

If you have a shower with a slanted floor and the slope covers ¼ inch per foot, 3 feet away from the drain, then you have ¾ inches already integrated so you only need a curb that is 1 and ¼ inches high.

Do You Have to Waterproof a Shower Curb?

You do not need to waterproof a shower curb if you are installing a pre-made one-piece shower stall.

The manufacturers have designed the unit to be waterproof already. If you intend to build and tile the shower yourself, then you must also create your own shower curb and waterproof it as well.

To waterproof a shower curb, use a moisture barrier such as a PVC pan liner or sheeting. A liquid moisture barrier that can be painted directly onto the wooden surface of the shower curb will also work.

Coating the wood with cement and then applying a thin layer of liquid moisture is yet another option.

What is a Shower Curb Made From?

In most cases, shower curbs are made from pressure-treated lumber because is both strong and water-resistant. They can also be made with cement or wood that has been coated with cement. You must still add a moisture barrier, however, to prevent moisture from seeping into the wood and causing it to rot.

While most prefabricated shower curbs are made from rubber, the Schluter Kerdi-Board-SC is made of kerdi-board (a multifunctional tile substrate and building panel) and used with the Schulter-Shower System.

It is waterproof and ready to tile. The only you need to do is seal the joints and corners!

Is it Necessary to Have a Shower Curb?

If you think a shower curb could be a potential tripping hazard, then you can opt for the curbless shower option. Before you begin, however, you should consult with your local building inspector to make sure everything is ‘up to code’.

The key to a curbless shower is the slope of the floor. It should be gradual otherwise the slope itself will be hazardous when wet and could cause a slip-and-fall accident.

This design requires a structural drop in the flooring and should be noted during the pre-construction phase of the building.

How Do You Build a Shower Curb?

To build a shower curb yourself, follow these 15 steps (example video at the end of this list):

  1. Begin by stacking 2 2X4’s on top of each other – cut them to fit the length of your shower entrance and then screw them securely to the floor with non-corrosive screws.
  2. Cover the curb completely with a waterproof pan liner that will then extend onto the floor and up the walls about 7 or 8 inches – be careful not to puncture the liner.
  3. Remove the top half of the drain flange and lay the liner – replace the bolts afterward.
  4. Cut out the liner around the drain in a circular fashion – the hole should reach the bolts at the bottom of the drain flange.
  5. Unscrew the 4 bolts from the drain and apply a ring of silicone under the liner onto the bottom of the drain flange – avoid getting any silicone into the bolt holes.
  6. Press the pan liner onto the ring of silicone and screw in the top of the drain flange gently so as not to crack it.
  7. Set the liner evenly into the corners and up against the walls – secure it with tape.
  8. At the two corners opposite the curb, take the liner and fold it over onto itself.
  9. At the edges of the curb, cut the liner vertically where the curb meets the wall – lay the liner flap over the curb making sure it is covered completely.
  10. Cover the curb with metal lath – put tape over the edges to prevent it from puncturing the liner.
  11. Add a layer of mortar or cement onto the curb about 1 inch thick. Place a straightedge on top and press down firmly to create suction.
  12. Apply an additional layer of mortar (about ½ inch thick) to the outside of the curb while the straightedge is still on it. Remove any excess mortar with a flat trowel.
  13. Once the inside mudding is complete, take a break for an hour to allow time for the mortar to harden.
  14. After an hour, take your flat trowel and go over the curb again to ensure it matches the height of your shower door. Check that the inside and outside of the curb are parallel to each other.
  15. Proceed to tile the shower – start with the sides and then do the top of the curb.

What is a Good Manufactured Shower Curb?

One of the best ways to create a shower curb is to purchase a manufactured shower curb and then customize it to fit your existing shower.

It not only makes the job easier, but it also helps speed the process along. Plus, it ensures that you get the best moisture protection possible.

A good one to check out online through Amazon is the Duzzy 66-Inch Shower Threshold Water Dam. It is a great choice as it is made from 100% waterproof rubber. Easy to both cut and clean, this thing can also be molded into a variety of shapes to fit almost any shower design.

It is ideal for both curbless showers as well as other areas where water needs to be contained.

A great value for your money, it is thick, sturdy, and highly-adhesive. Do yourself a favor – go online and check it out today!

Also, check this video:


To summarize, the typical height for a shower curb according to building code in the United States is 2 inches above the top of the drain.

This does not mean, however, that the curb itself must be 2 inches high. It depends on whether you have a shower floor that slopes down towards the drain or not.

Hopefully, this article has been of help to you. Thanks for reading and good luck!

Cheers, tools owners!

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Hi there! My name is Jack and I write for ToolsOwner. I have a passion for everything related to tools and DIY projects around the house. You often find me in my workshop working on new projects.