Whether you’re building a home from scratch or installing a standalone shower in your master bathroom, you will soon find that shower curbs are more important than you thought. While some homeowners are free to do as they please, some counties and circumstances require that shower curbs meet certain building requirements.
Building codes in most locations require shower curbs to be at least two inches (2”) above the drain. However, this doesn’t mean that your shower curb needs to be exactly two inches high, especially if your shower slopes down towards the drain.
Let’s take a look at how you’ll need to set up your shower curb. We’ll also examine how to measure from the top of your drain so your shower curb doesn’t end up too small.
Shower Curbs 101
The shower curb is an important part of your standalone shower. This small ‘lip’ at the entrance to your shower helps to keep water from flooding your bathroom.
While it might seem pointless (especially with a sloped shower floor), it can help a great deal if there’s an unexpected clog or if the drain is covered during your shower.
If you happen to stand over the drain or drop an object so that the drain is covered, water can quickly fill up the bottom of the shower. If it spills over onto your bathroom floor, you may permanently damage your floors.
Water damage can lead to a host of problems. Among these are mold, structural problems, mildew, discoloration and distortion of tiles, and odor.
Needless to say, your shower curb must be high enough to contain any extra water from your shower.
Requirements for Your Shower Curb
Here’s a checklist to make sure that your shower curb will keep water from damaging your bathroom floors.
According to H2ouse.org and most state building codes, shower curbs must be:
- Lined with moisture-resistant barrier material (like PVC sheeting)
- Solid and secure to the floor of the shower
- At least 2” from the top of the drain in most locations
- No more than 9” from the top of the drain
- Measurable from the outside bathroom floor
- Ideally, mortared or set with concrete to preserve its longevity
How Can a Sloped Floor Help?
Simply put, a sloped floor is a key to making the smallest possible shower curb that still adheres to building codes. While most showers should slope towards the drain, you’ll need a deeper slope if you want to avoid having a taller shower curb.
If you have enough room, you can slope the floor of the shower deeply enough to have a shorter shower curb. But you have to make sure that the slope is gentle and gradual. Otherwise, it can become a hazard.
A slope of about ¼” per foot is usually safe and effective. You can stand on it without it becoming dangerous and water will fall into the drain.
Here’s a quick comparison table to reference for your shower curb based on a ¼” per foot slope.
|Distance from Drain||Required Height of Shower Curb|
|1ft (12 inches)||1-3/4”|
|2 ft (24 inches)||1-1/2”|
|3 ft (36 inches)||1-1/4”|
|4 ft (48 inches)||1”|
As you can see, larger showers may require shorter shower curbs. If you have a more gradual per foot slope, you’ll need to calculate your numbers.
How to Measure Your Shower Curb
There are two different ways to measure your shower curb. You can take the height of the curb from the drain, or you can do an external measurement.
Measuring from the Drain
To measure from the shower drain, you’ll need two measuring implements. You can use tape measures, rulers, or yardsticks to try and get an accurate measurement.
Place one end of the measuring device on the drain itself and lay the other across the top of the curb, making sure to keep both straight as they intersect. When used correctly, the intersection of these implements will tell you how high the shower curb is from the drain.
Remember that in most cases, this must be at least 2” and not more than 9”.
To measure the exterior of your shower curb, measure the distance from your bathroom floor to the top of the shower curb.
This is not the measurement that you’ll use to determine if your shower curb meets building code requirements, but it can help you choose materials and more.
For instance, if the shower curb is 1-½” high at the external measurement, you’ll know what you need to repair or replace it. Alternatively, you can use this measurement to plan shower door installation and more.
How to DIY Your Shower Curb
Installing your shower curb is simple, but it takes some construction expertise to complete. You can’t just put any material across the front of your shower and call it a curb: materials must be sturdy, waterproof, and sealed.
Sunrise Specialty goes into great detail about how to plan your shower curb. Essentially, you have to get your measurements correct, line the area under your shower, and make sure that the shower liner never gets punctured. This is the last line of defense between the water in your shower and the wood beneath.
Once you have the liner in place, you’ll need to cover it with metal lath. This is a type of metal mesh that helps protect the liner and shape the curb. Make sure not to puncture the liner and keep your hands away from the sharp edges of the lath.
Once the lath is shaped and in place, you will mortar around the lath to provide a surface for the tile and other finishing materials. After the mortar hardens, you can finish the curb off with tile and waterproofing.
Make sure that you are using the right tools and understand the materials that you’re working with.
Curbless Shower Designs
For accessibility reasons, you may need a curbless shower. If this is the case, make sure to contact the local building authorities to find out what you can do. Make sure that your bathroom floor is lined and waterproofed properly to avoid damage.
With a large enough shower, you may be able to create a slope large enough to eliminate the need for a shower curb. This requires careful planning and should only be attempted after contacting your local building authorities.
US Building Code Restrictions
It’s important to note that each state, county, and even municipal district may have different building restrictions. If you are building a shower for a rental property or a remodel on a house you plan to sell, you have to make sure to adhere to the restrictions in your area.
Most states have a flat standard: the shower curb must be at least 2” high when measured from the drain and less than 9” high in total. Section 411.6 of the ICC (International Code Council) lays this rule down, though other laws may extend how high a curb must be.
Make sure that you know the regulations in your state and local area so that your builds always pass the code inspection if one is required.
While shower curbs may seem unnecessary to some, they are very important for the long-term health of your bathroom floors. Additionally, most building codes require shower curbs of a certain height to be installed on standalone shower stalls.
Keep these requirements in mind when you’re building or renovating your bathrooms to avoid fines and building code violations.
As a homeowner, I am constantly experimenting with making the structure of my house more energy-efficient, eliminating pests, and taking on DIY home improvement projects. Over the past two decades, my family has rehabbed houses and contracted new home builds and I’ve learned a lot along the way. I share my hard-learned lessons so that you can save time and money by not repeating my mistakes.