What to Do When Your Shower Tile Starts Cracking After Installation

The Cracks That Should Not Be There

Your bathroom remodel was completed a few months ago. The new shower looked perfect on day one: clean lines, beautiful tile, crisp grout joints. Then you notice a crack. Maybe it is a hairline fracture in the grout. Maybe a tile has split. Maybe several tiles are developing a network of fine cracks in the same area.

Cracking tile in a brand-new shower is not normal wear and tear. It is a symptom of an installation problem, and how you respond determines whether it stays a minor issue or grows into a major one involving water damage, mold, and a complete tear-out.

Why Shower Tile Cracks After Installation

Understanding the cause is essential to choosing the right fix. Here are the most common reasons shower tile fails prematurely.

Improper Substrate

The substrate (the surface behind the tile) is the foundation of any tile installation. In a shower, the substrate must be dimensionally stable, moisture-resistant, and rigid enough to support the tile without flexing.

What goes wrong: Some installers use regular drywall (green board or even standard white board) in showers. Drywall absorbs moisture over time, swells, softens, and eventually crumbles. As the substrate moves, the tiles bonded to it crack and pop loose.

What should be used: Cement backer board (Hardiebacker, Durock), foam board systems (Schluter KERDI-BOARD, wedi), or fiber cement board. These materials do not absorb water and provide a stable surface for tile adhesion.

Missing or Inadequate Waterproof Membrane

A waterproof membrane is a barrier between the tile and the substrate that prevents water from reaching the framing behind the shower. Without it, moisture passes through grout joints (grout is not waterproof) and reaches the substrate and framing.

What goes wrong: Many budget installations skip the waterproof membrane entirely or apply it inconsistently, leaving gaps at seams, corners, and penetrations. Water finds these gaps, saturates the substrate, and causes swelling, mold, and eventually tile failure.

What should be used: A continuous waterproof membrane system. Options include sheet membranes (Schluter KERDI), liquid-applied membranes (RedGard, Hydroban, Laticrete Hydro Ban), or hot-mop waterproofing (traditional in California). The membrane must cover every surface that will be exposed to water, with sealed seams and sealed penetrations at valves, showerheads, and niches.

Wrong Thinset Mortar

Thinset is the adhesive that bonds tile to the substrate. There are two primary types:

• Modified (polymer-modified) thinset: Contains latex or polymer additives for improved bond strength and flexibility. Cures by both chemical reaction and evaporation.
• Unmodified thinset: Standard Portland cement-based mortar that cures by hydration.

What goes wrong: Using the wrong type for the substrate and membrane combination. For example, modified thinset over a Schluter KERDI membrane can prevent proper curing because the membrane blocks moisture evaporation. Using unmodified thinset in an application that needs flexibility can result in bond failure.

What should be used: Follow the membrane manufacturer’s specific recommendations. Each system has tested and approved thinset pairings.

No Movement Joints

Tile and grout are rigid materials bonded to a surface that experiences thermal expansion, moisture cycling, and minor structural movement. Without relief, these forces crack the tile or grout.

What goes wrong: Grout is applied in every joint, including corners (where walls meet walls) and transitions (where tile meets the tub, shower pan, or ceiling). These are all movement zones that need flexible sealant, not rigid grout.

What should be used: Silicone or urethane caulk (color-matched to the grout) at all inside corners, where tile meets the tub or shower pan, and at any change in plane. These joints are called “movement joints” or “expansion joints” and are required by tile industry standards (TCNA Handbook).

Structural Deflection

If the wall framing or floor structure behind the tile flexes too much, the rigid tile surface cannot accommodate the movement and cracks.

What goes wrong: Walls framed with studs spaced 24 inches on center (rather than 16 inches), undersized floor joists beneath a shower base, or inadequate blocking behind heavy tile installations.

What should be used: Wall studs at 16 inches on center maximum behind tile. Cement board must be fastened according to manufacturer specifications (typically every 8 inches on edges and every 12 inches in the field). Floor deflection should not exceed L/360 for tile installations.

What to Do Step by Step

Step 1: Assess the Severity

Before calling anyone, evaluate the situation:

Cosmetic cracking indicators:

• One or two cracked tiles in an isolated location
• Grout cracking at a corner or transition (movement joint issue)
• A tile with a single crack that is not growing
• Tiles feel solidly bonded when pressed (no hollow sound, no movement)
• No signs of water damage on surrounding surfaces

Systemic failure indicators:

• Multiple tiles cracking in a pattern
• Tiles that sound hollow when tapped with a knuckle
• Tiles that flex or move when pressed
• Grout falling out of multiple joints
• Water stains or dampness on the wall or ceiling below the shower
• Musty or moldy smell near the shower
• Mold visible in grout joints or at the base of the shower

Step 2: Contact the Original Installer

If the tile was installed recently (within the past year), contact the installer or contractor who did the work. A reputable installer will stand behind their work and come back to assess the situation. Ask about their warranty terms and what they cover.

Be prepared for the possibility that the installer may minimize the issue. If they offer a cosmetic fix (replace one tile, regrout a corner) but you suspect a systemic problem, get a second opinion from an independent tile professional.

Step 3: Get a Professional Assessment

For anything beyond clearly cosmetic cracking, hire an experienced tile contractor or a building inspector to evaluate the installation. They should:

• Tap tiles across the shower to check for hollow spots (indicating bond failure)
• Check for moisture behind the tile using a moisture meter
• Examine the substrate type and condition (if accessible from the back side or through a single removed tile)
• Evaluate whether a waterproof membrane was installed
• Assess the grout and caulk joints for proper placement

This assessment typically costs $200 to $500 and gives you a clear picture of whether you need minor repairs or a full redo.

Step 4: Decide Between Repair and Redo

Repair is appropriate when:

• Cracking is limited to grout joints at movement zones (just needs caulk)
• One or two tiles cracked from impact or a manufacturing defect
• The substrate and waterproofing are intact
• Tiles are well-bonded throughout the rest of the shower

Full tear-out and redo is necessary when:

• The substrate is wrong material (drywall in a shower)
• No waterproof membrane was installed
• Multiple tiles are debonding across a large area
• Water damage has reached the framing
• Mold is growing behind the tile

Step 5: Get It Done Right the Second Time

If a tear-out is necessary, treat it as an opportunity to do the job correctly. Insist on:

• Cement board or foam panel substrate
• A complete waterproof membrane system (Schluter KERDI, RedGard, or equivalent)
• Manufacturer-approved thinset for the membrane system
• Movement joints (caulk, not grout) at all corners and transitions
• Proper substrate fastening per manufacturer specs
• Sloped mortar bed or pre-sloped foam pan for the shower floor

Costs of Fixing Cracking Shower Tile

Repair Type	Cost Range
Replace caulk at movement joints	$100-$300
Replace 1-3 individual tiles	$200-$600
Regrout entire shower	$400-$800
Full tear-out and redo (standard shower)	$3,000-$7,000
Full tear-out and redo (large/custom shower)	$7,000-$12,000
Additional: framing repair if water damage exists	$1,000-$5,000

How to Prevent Tile Cracking

Hire an Experienced Tile Installer

The most effective prevention is hiring a tile installer who follows industry best practices. Ask prospective installers:

• What substrate do you use in showers?
• What waterproof membrane system do you install?
• What thinset do you use, and is it approved for your membrane system?
• Do you use caulk at movement joints?
• Are you familiar with TCNA (Tile Council of North America) installation standards?

Their answers will tell you whether they understand proper shower tile installation.

Specify the Waterproofing System

Do not leave the waterproofing system to chance. Specify the system you want (Schluter, RedGard, or equivalent) in the project scope of work. Get a line item for it in the contract so there is no ambiguity.

Require a Pre-Tile Inspection

Before any tile goes on the wall, walk the shower with your contractor and verify:

• The correct substrate is installed and properly fastened
• The waterproof membrane is continuous with sealed seams and penetrations
• The shower pan slopes to the drain (test with a ball or level)
• All curbs are waterproofed
• Niches are lined with waterproof membrane

This 15-minute inspection can save thousands in future repairs.

Document the Installation

Photograph the substrate, membrane, and key stages of the tile installation. These photos serve as a record of what is behind the finished surface, which is valuable if questions arise later.

When to Call a Professional

Call an experienced tile contractor or building inspector if you observe:

• Cracking tile in a shower that is less than two years old
• Multiple tiles with cracks in the same area
• Tiles that feel loose or hollow
• Persistent mold in grout joints despite regular cleaning
• Water stains on the ceiling below a bathroom
• A spongy or soft feeling in the shower floor

These signs indicate potential waterproofing or substrate failure that will worsen over time. Early intervention prevents the damage from reaching the structural framing.

Why Custom Home Design and Build

Tile installation quality is one of the areas where design-build firms distinguish themselves. At Custom Home, our tile work follows industry best practices without exception.

Every shower we build includes a waterproof membrane system, proper cement board substrate, manufacturer-approved thinset, and caulked movement joints at all corners and transitions. We do not cut corners because we stand behind every project we complete.

Our project managers inspect tile installations at multiple stages: substrate verification, membrane application, and in-progress tile work. We photograph the waterproofing before it is covered by tile, creating a permanent record of the installation for your files.

If you are dealing with cracking tile from a previous installation or planning a new bathroom remodel, our team ensures the work is done right from the substrate out.

Contact us to discuss your bathroom project with a team that treats tile installation as the craft it is.