Here's a fact that surprises many homeowners: tile is not waterproof. Neither is grout. Without proper waterproofing behind the tile, water will eventually penetrate your walls and floors, leading to mold, rot, and structural damage. This article explains why waterproofing matters and how professionals do it right.
The Hidden Danger of Poor Waterproofing
We regularly repair showers where water has been leaking behind the tiles for years. By the time homeowners notice (usually a musty smell or soft spots in walls), the damage can cost $5,000-$15,000+ to repair—compared to $500-1,000 for proper waterproofing during initial installation.
What Is Tile Waterproofing?
Waterproofing creates a water-resistant barrier between your tile and the structure of your home. It's applied to the substrate (backer board, concrete, etc.) before tile installation, ensuring that any water that gets through the grout or tile joints doesn't reach the wood framing, drywall, or subfloor behind it.
Where Is Waterproofing Required?
Shower walls and floors
Direct water contact makes waterproofing essential
Tub surrounds
Splash zones need protection
Steam showers
Requires ceiling waterproofing too
Bathroom floors
Protects against overflow and splashing
Kitchen backsplashes
Not typically required (minimal water exposure)
Types of Waterproofing Systems
1. Liquid-Applied Membranes
Painted or rolled onto surfaces, these form a seamless waterproof coating:
- • RedGard: Popular, affordable, easy to apply
- • Hydroban: Professional-grade, quick-drying
- • AquaDefense: Premium option with excellent flexibility
Pros: Affordable, seamless coverage, easy to apply around corners and curves
Cons: Requires proper thickness (multiple coats), drying time between coats
2. Sheet Membranes
Pre-formed waterproof sheets that are adhered to surfaces:
- • Schluter DITRA: Uncoupling membrane with waterproofing
- • Kerdi: Thin sheet membrane for walls and floors
- • NobleSeal TS: Premium chlorinated polyethylene
Pros: Consistent thickness, immediate coverage, some provide crack isolation
Cons: Higher material cost, seams require proper treatment
3. Foam Shower Panels
Pre-sloped, pre-waterproofed panels that serve as both substrate and waterproofing:
- • Schluter Kerdi-Board: Foam panels with fleece coating
- • Wedi: German-engineered foam panels
- • GoBoard: Lightweight, easy-to-cut panels
Pros: Built-in waterproofing, lightweight, easy to shape for niches and benches
Cons: Highest material cost, requires system-specific adhesives
Critical Areas That Need Special Attention
Corners and Transitions
Inside corners where walls meet floors or other walls need reinforcing fabric or pre-formed corner pieces. These are stress points where cracking can occur.
Shower Curb
The curb is often where water intrusion begins. Proper waterproofing wraps over the top and down both sides of the curb.
Drain Connection
The connection between the waterproof membrane and drain is critical. Many systems use specific drains designed to integrate with the membrane.
Niches and Benches
Built-in features have multiple corners and transitions. Each must be properly waterproofed, especially horizontal surfaces that collect water.
Valve and Fixture Penetrations
Every pipe and valve that penetrates the waterproof membrane needs proper sealing with appropriate materials.
Signs of Waterproofing Failure
If you notice any of these, have your shower inspected immediately:
- ⚠Musty or moldy smell in the bathroom
- ⚠Soft or spongy spots in walls near shower
- ⚠Stains or bubbling paint on adjacent walls
- ⚠Loose or hollow-sounding tiles
- ⚠Cracked or crumbling grout that keeps returning
- ⚠Water damage on ceiling below bathroom
Why Professional Installation Matters
Waterproofing mistakes don't show up immediately—they can take months or years to manifest. By then, damage behind the walls can be extensive. Professional installers:
- Know proper application thickness and techniques
- Use compatible products that work together as a system
- Understand critical details at corners, curbs, and drains
- Test waterproofing before tiling (flood test)
- Stand behind their work with warranties
Proper Waterproofing Included in Every Russell Tile Shower
At Russell Tile, professional waterproofing is standard in every shower installation—never an upsell or shortcut. We use proven systems and stand behind our work. Contact us for a free consultation.
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