Optimal Shower Curb Size: A Comprehensive Guide for Your Bathroom Design

The shower curb height in the United States is a minimum of 2 inches above the drain. The suggested minimum width is 36 inches, with an acceptable range of 42 to 48 inches. Compliance with building code entails ensuring a 2-inch drop from the drain location to the stepping-in point, rather than a strict 2-inch curb height.

Understanding the appropriate dimensions of a shower curb, let’s delve deeper into this subject. The following sections will cover the definition of a shower curb, its significance, and proper construction methods. Additionally, I’ll provide insights into crafting a curbless shower and offer guidance on acquiring pre-made shower curbs.

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

Shower Curb Definition

A shower curb functions to contain water within the shower, preventing leakage onto the bathroom floor. It serves as the boundary between the shower pan base and the bathroom floor, also known as a shower threshold or dam.

Shower curbs are available in constructed or purchased forms. Typically crafted from wood or concrete, they can also be manufactured using rubber.

Shower curbs serve as the initial defense against water damage and should be constructed or installed in adherence to building code regulations.

Shower Curb’s Purpose

The shower curb’s primary purpose is to contain water within the shower area. Additionally, it can serve as a base for attaching brackets for a shower door.

In the event of a water pipe backup or drain clog, the shower curb serves as a temporary safeguard until the plumbing issue is rectified.

Although the minimum curb height is 2 inches, it doesn’t imply the curb must be precisely 2 inches high.

In a shower with a sloped floor at a rate of ¼ inch per foot, if the slope covers 3 feet from the drain, ¾ inches are already factored in. Consequently, a curb height of 1 and ¼ inches would suffice.

Shower Curb Waterproofing

Waterproofing a shower curb is unnecessary when installing a pre-made one-piece shower stall, as manufacturers design these units to be inherently waterproof.

However, if you opt to construct and tile the shower yourself, it’s imperative to craft your own shower curb and ensure its waterproofing.

For shower curb waterproofing, employ a moisture barrier like a PVC pan liner or sheeting.

Alternatively, a liquid moisture barrier that can be directly applied to the wooden surface of the shower curb is effective. Another option involves coating the wood with cement and applying a thin layer of liquid moisture.

Shower Curb Composition

Typically, shower curbs are crafted from pressure-treated lumber due to its strength and water-resistant properties.

Alternatively, they may be constructed with cement or wood coated in cement.

Nonetheless, it’s crucial to incorporate a moisture barrier to prevent wood rot by inhibiting moisture infiltration.

While the majority of pre-made shower curbs use rubber, the Schluter Kerdi-Board-SC is constructed from Kerdi-board, a versatile tile substrate and building panel. It is specifically designed for use within the Schluter-Shower System. It comes waterproofed and ready for tiling. Just ensure to seal the joints and corners!

Necessity of a Shower Curb

If you’re concerned about a potential tripping hazard with a shower curb, consider the curbless shower alternative. Before initiating the process, it’s advisable to consult your local building inspector to ensure compliance with the applicable building codes.

The critical aspect of a curbless shower is the floor slope. It must be gradual to prevent the slope itself from becoming a wet hazard, reducing the risk of slip-and-fall accidents.

This design necessitates a structural drop in the flooring, and it’s essential to take note of this requirement during the pre-construction phase of the building.

Constructing a Shower Curb

To construct a shower curb on your own, follow these 15 steps:

1. Begin by stacking two 2X4s, cut to fit the shower entrance length, and securely screw them to the floor using non-corrosive screws.
2. Completely cover the curb with a waterproof pan liner, ensuring it extends onto the floor and up the walls about 7 or 8 inches. Be cautious not to puncture the liner.
3. Remove the top half of the drain flange, lay the liner, and replace the bolts.
4. Cut the liner in a circular fashion around the drain, reaching the bolts at the bottom of the drain flange.
5. Unscrew the four bolts from the drain, apply a ring of silicone under the liner onto the bottom of the drain flange, avoiding silicone in the bolt holes.
6. Press the pan liner onto the silicone ring and gently screw in the top of the drain flange to prevent cracking.
7. Set the liner evenly into the corners and against the walls, securing it with tape.
8. Fold the liner over itself at the two corners opposite the curb.
9. Cut the liner vertically at the edges where the curb meets the wall, laying the liner flap completely over the curb.
10. Cover the curb with metal lath, placing tape over the edges to prevent puncturing the liner.
11. Apply a 1-inch thick layer of mortar or cement onto the curb. Place a straightedge on top and press down firmly for suction.
12. Apply an additional ½-inch thick layer of mortar to the outside of the curb while the straightedge is still in place. Remove excess mortar with a flat trowel.
13. Take a one-hour break to allow time for the mortar to harden after completing the inside mudding.
14. After an hour, use a flat trowel to ensure the curb matches the height of your shower door. Verify that the inside and outside of the curb are parallel.
15. Proceed to tile the shower, starting with the sides and then covering the top of the curb.

Recommended Manufactured Shower Curbs

An efficient approach to crafting a shower curb involves acquiring a manufactured one and customizing it for your existing shower.

This not only simplifies the task but expedites the process while ensuring optimal moisture protection.

A recommended option available on Amazon is the Duzzy 66-Inch Shower Threshold Water Dam. Crafted from 100% waterproof rubber, it’s easily cut and cleaned, and can be molded into various shapes to suit diverse shower designs. Ideal for curbless showers and areas requiring water containment, this product offers excellent value with its thickness, sturdiness, and strong adhesive properties. 

Closing Thoughts

In summary, the standard building code in the United States mandates a shower curb height of 2 inches above the drain’s top.

However, the actual curb height varies, contingent on whether your shower floor slopes towards the drain or not.

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

Cheers, tools owners!

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.