Your shower walls should be prepped and tiled according to the International Residential Code and applicable local regulations. The general code for residences states that shower walls must have a nonabsorbent surface finish. Check your local building codes, too, for specific guidelines.
You should waterproof all the shower walls before tiling. A tile backer or cement board is typically not waterproof, albeit many are water-resistant. The most effective and reliable solution is a separate waterproofing membrane on primed shower walls before tiling.
The market has a plethora of products using interchangeable & poorly defined terms, such as mastic, water-resistant, nonabsorbent, and waterproof.
Eliminate all ambiguity and uncertainty by waterproofing shower walls before tiling using one of the solutions in this guide.
Why Should I Waterproof Shower Walls Before Tiling?
Not all tiles are nonabsorbent. Glazed ceramics are nonporous, and porcelain is impermeable.
However, tile backers or cement boards claiming to be nonabsorbent, water-resistant, or having a waterproofing membrane aren’t necessarily failsafe for your shower walls before tiling.
Tile glues, cement, backer boards, and any built-in water-resistant membrane do not waterproof your shower walls. Water or moisture will seep through the grouts of the tiles sooner or later. Thus, preventable mold growth and stud rot will become inevitable.
Take mastic, for example. The ambiguous term is not widely used on labels, but mastic is still available in different forms.
Do not use mastic for your shower walls as it is meant for damp places at best, not where you will have a mini water park. Also, thinset poses a few challenges.
The sheer variety of thinset complicates the process of choosing one. Then, there is a modified thinset with varying proportions of latex and other materials.
One typical challenge with many thinset solutions is the likelihood of tiles sagging as the material takes a while to cure and dry.
How To Waterproof Shower Walls Before Tiling
Consider one of these reliable solutions to waterproof your shower walls before tiling:
- USG Durock
- Hydro Ban
- Waterproof Membranes
Standard thinset is not water-soluble and thus will not dissolve, liquefy, or degrade when exposed to water, even when it is submerged.
However, it isn’t waterproof. Also, modified thinset or variants containing latex are more water-resistant but still not truly waterproof.
Likewise, Diamondback is water-resistant, not waterproof. Hence, it is not an ideal solution for shower walls or the pan on the floor.
You must choose a material that is actually waterproof, one totally immune to water, and completely impermeable to prevent water or moisture seepage.
RedGard Elastomeric Waterproofing Membrane
You may consider Custom LQWAF3 Gard Waterproofing available on Amazon.com.
This pack is 3.5 gal (13.2 liters), which you will need for at least two and preferably three coatings on all the shower walls and the floor.
RedGard is an excellent option.
Here’s a video to assist your DIY RedGard application:
ARDEX S 1-K One Component Waterproofing
ARDEX S 1-K One-Component Waterproofing on Amazon.com is another reliable option.
This flexible waterproofing coating is easy to apply on interior walls & floors with a brush or roller and ensures crack isolation for ~3 mm (0.11 inches).
You can apply this liquid membrane on drywall. The manufacturer recommends two coats and 1 gal (3.78 liters) is sufficient for 56.75 sq ft or 5.27 sq m.
Furthermore, you can use Ardex for the tiles on your shower walls, bathroom floors, dados or kitchen backsplashes, and stones.
Schluter Kerdi Shower Kit
Schluter Kerdi Shower Kit, on Amazon.com, includes a 2 inches (50.8 mm) PVC flange, a stainless steel grate, and joint sealant.
Also, you get a pre-sloped shower tray and prefabricated components for snug onsite installation.
You don’t need a mortar bed to use this full kit. The all-inclusive kit has valve & pipe seals, strainer, and high-density polymer membranes for inside & outside corners.
The impeccable waterproofing solution has 15 years of warranty from Schluter Systems if installed correctly.
USG Durock Liquid Waterproofing Membrane
USG Durock Brand Liquid Waterproofing available on Amazon.com is similar to RedGard and Ardex.
Like the latter, Durock serves as a crack isolation membrane. Also, the liquid-applied waterproofing solution is a vapor retarder and is thus practically suitable for steam showers.
You may install USG Durock on concrete, cement backer board, masonry, and gypsum panel or topping.
Furthermore, you may brush, roll, trowel, or spray the material on the wall and floor substrates in your shower area.
The brand recommends one coat for walls and two for floors.
Hydro Ban Ruber Polymer Membrane
Laticrete’s Hydro Ban available on Amazon.com is another popular option.
The waterproofing and crack isolation membrane is load-bearing and self-curing rubber polymer in liquid form.
You can apply two coats of Hydro Ban directly on all standard shower walls & floor substrates and tub decks.
Tile Underlayment Waterproof Membranes
Some homeowners may prefer a solid waterproofing membrane instead of self-curing coatings.
This Snap membrane can cover 108 sq ft (10 sq m), and there is one for 54 sq ft (5 sq m). The 0.125 inches (~3 mm) membrane is a tile underlayment for stone, ceramic, and porcelain.
The membrane can prevent tile cracking, and its polyethylene top layer ensures waterproofing.
UCANVIN’s 0.3 inches (8 mm) thick shower membrane is sufficient for 108 sq ft (10 sq m). Also, there are Ucanvin Store Uncoupling Membrane Tile Underlayment 54 sq ft (5 sq m) and Ucanvin Store Waterproof Membrane Band Roll 216 sq ft (20 sq m) variants available on Amazon.com.
The soft sheet membrane is ideal for shower walls and floors. Besides, you can use it for the entire bathroom floor if you want.
Here’s a video using a similar soft membrane to waterproof shower walls before tiling:
Always waterproof your shower walls before tiling, irrespective of the backer board, substrate, and other materials.
The preventive measure may cost you a few hundred dollars now, but you will save several thousand that would be inevitable for the extensive repair & restoration later.
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