Shower Curb Height and the Best Cap: Tile, Marble or Quartz

A shower curb is the low wall at the shower entry that holds water inside the shower until it reaches the drain. Most shower curb height lands around 4 to 6 inches above the bathroom floor. That is tall enough to hold water back and low enough to step over. The top of the curb, called the cap, should slope slightly back into the shower. For the cap, we prefer one solid piece of marble or quartz over cut tile, because it has no grout joints on top where water sits.

Key Takeaways

• Height: most curbs finish about 4 to 6 inches above the bathroom floor.
• Slope the top. The cap tilts toward the shower so water runs back in, not out.
• Best curb core: a Schluter Kerdi foam curb or a mortar curb. We do not build curbs from wood, because wood rots when it gets wet.
• Best cap: a solid Anatolia Marmiline marble piece or a quartz piece. One piece means no grout on the top.
• Cracked curbs leak. Water that gets into a curb often shows up on the bathroom floor or the ceiling below.

Building a new shower, or is your old curb cracked? Send us photos of your shower curb for a same-day curb and tile shower estimate. A close-up of the curb top and both ends shows us a lot.

This article covers curbs only. For the full build, go Back to Tile Shower Installation or read our Bathroom Tile Installation Complete Guide.

How High Should a Shower Curb Be?

A shower curb should stand about 4 to 6 inches above the bathroom floor. The exact height depends on the shower floor inside it. The shower floor slopes about 1/4 inch per foot toward the drain, so its highest point is at the curb. The curb has to clear that high point with room to spare.

• Too low: water can spill over during a long shower or if the drain slows.
• Too high: it becomes a trip hazard, and stepping over gets harder with age.
• Width: wide enough to stand on safely and to hold a glass panel if you plan one.

If you want no step at all, the floor has to be recessed instead. Our is a curbless shower worth it article covers that trade-off. A low curb is a good middle ground when the floor framing cannot drop.

What Are Shower Curbs Made Of?

Shower curbs are made of foam, brick or packed mortar, then waterproofed and tiled. The core matters because it has to stay solid and dry for decades. Here is how the three compare:

• Schluter Kerdi foam curb: light, straight and pre-made. It pairs with a Kerdi foam tray, and Kerdi-Band seals it to the tray and the wall. This is our usual choice with a tray.
• Mortar curb: packed sand and cement shaped by hand. It pairs with a traditional mud pan and can be any length or shape.
• Brick curb: stacked brick wrapped in mortar. It is strong and old-school, and it is common in older Boston homes we tear out.
• Wood curb (2x4s): we do not use it. If water ever reaches the wood, it swells and rots, and the tile on top cracks.

Every curb gets waterproofed with the rest of the shower. On a Kerdi tray, the curb is wrapped and banded to the tray. The walls get RedGard, and Kerdi-Band goes only where the tray or curb meets the wall. Our RedGard vs Kerdi article explains how those two systems meet. For tray vs mud pan, see kerdi shower pan vs mud.

What Is the Best Shower Curb Cap?

The best shower curb cap is a single solid piece of stone or quartz. One piece has no grout joints on the flat top, where water sits after every shower. Tile works too, but it puts more grout right where the curb takes the most water. Here is how the options compare:

Is a marble shower curb a good idea?

Yes, if you are fine with sealing it. Marble is porous and can etch from acidic products, so it needs sealing before grouting and about once a year after. In return, you get one clean piece with no grout on top. We set marble caps with a slight slope into the shower, so water does not sit on the stone. Many homeowners pick the same marble for the niche sill. Our shower niche dimensions guide covers that pairing.

Does a curb cap need to slope?

Yes. The cap should tilt slightly toward the shower. A flat cap holds water. A cap that tilts out sends water onto the bathroom floor. If you are adding a glass panel, the glass installer works with that slope when they set the panel.

Why Do Cracked Shower Curbs Leak?

Cracked curbs leak because the curb is the one part of the shower that gets wet on three sides. Water hits the top, the inside face and the seam where the curb meets the floor. Once a crack opens, water gets into the core and moves outward. It often shows up on the bathroom floor, the baseboard or the ceiling below.

Signs your curb is leaking

• Cracked or missing grout along the top of the curb.
• A loose or rocking cap piece.
• Stains, swelling or soft spots on the floor just outside the shower.
• Peeling paint or stains on the ceiling under the shower.
• Caulk at the curb ends that keeps failing.

Fresh caulk will not fix a cracked curb. In most cases, we remove the curb, check the waterproofing under it and rebuild it tied into the shower pan. Our article on a shower leaking from the bottom walks through the other common causes.

What Does a Shower Curb Cost?

A curb is part of the shower floor price, not a separate line on most jobs. Replacing a leaking shower floor with a Kerdi tray and new curb, with the walls staying, runs $4,100 to $4,500 (as of 2026 pricing). A full shower tear-out and rebuild runs $5,000 to $7,000+ for labor and setting materials (as of 2026 pricing). Benches, stone sills and bigger showers push it up. Plumber and glass are extra. Most full showers take 4 to 8 working days. A solid marble or quartz cap adds the cost of that one piece. You buy the tile and choose the cap, and we supply the setting materials.

Ready to Get Your Shower Curb Right?

The right shower curb height is about 4 to 6 inches, with a cap that slopes back into the shower. Build the core from foam or mortar, never wood. Top it with one piece of marble or quartz when you can. Aguirre Modern Tile has built showers in Greater Boston since 2016. We are a registered Massachusetts home improvement contractor (HIC #655072) and fully insured. Send us photos for a same-day estimate on a new shower curb with a marble or quartz cap.