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Bath and shower installations make up a huge portion of projects installers undertake on a daily basis. They can also be the most problematic if not executed properly. For this reason, the standards and specifications presented by American National Standards Institute (ANSI) and the Tile Council of North America (TCNA) Handbook are indispensable to anyone attempting a tile shower or bath project. Just as important, though, is having the correct materials and applying them properly to help guarantee your work will leave customers with safe lasting tile surfaces.


Waterproof Properly

The average U.S. shower lasts 7.8 minutes and uses 15.8 gallons of water. That means a family of three runs approximately 17,000 gallons of water through the bath or shower tile assembly.  As far as that family knows, it is the grout keeping the water from compromising the tile system and damaging their home and possessions. As tiling professionals, we understand that it takes more to prevent installation failure.

Whether you are installing a “water in, water out” or sealed shower system, some form of concealed waterproofing system needs to be applied beneath the setting mortar on walls and adequately sloped floors. The flexibility and cost efficiency of waterproof membranes make them the go-to solution for many in our industry. The membranes’ primary functions are to prevent water from creeping beyond the setting mortar and to transport the water to the drain as quickly as possible. While there are many waterproof membrane systems available to installers, the two leading types are sheet and liquid applied.

Sheet membranes can be trimmed to size to fit most space requirements. They provide the same waterproofing protection as liquid-applied membranes but only if they are installed precisely to manufacturer specifications. Sheet membranes rely on the integrity of seams between sheets to prevent water infiltration. When not installed properly, these seams can create many points of failure that can upend an entire installation. This may result in property damages and a complete rip-and-replace of the tile installation.

Liquid-applied membranes deliver greater flexibility, as they can be brushed, rolled, troweled or sprayed on to accommodate any space or shape. The membranes form a thin continuous barrier free of seams and failure spots. They are easily integrated into any drain assembly to provide uninterrupted runoff from the sub-tile surface. Additional support and protection can be provided at change-of-plane areas by installing a product like SikaTile®-190 Reinforcing Fabric into the membrane system.  And the strength and elongation of these liquid-applied membrane systems grant exceptional crack isolation, inhibiting the transfer of fractures 1/8 inch wide to the tile surface.


Find the Right Mortar

Once your shower or bath is waterproofed and flood tested, you can start laying your tile.  However, it is important to ensure that your mortar is suitable for the environment in which it will be holding tile. The mortar needs to be able to hold up to intermittent to continual water exposure, supporting the tile or stone for decades. Organic mortars, also known as tile mastics, are a non-starter due to their ability to host mold, so high-performance cementitious tile mortars will produce the best all-around results.


TILE 0622 Technical Focus Merkete 02 Mortar

Photo courtesy of Sika


It is also imperative to be sure the mortar’s strength and properties are suitable for the tile or stone type your customers want. Do they want a stone mosaic floor? Are they asking for subway tile on the tub surround? You may need more than one type of tile mortar for the bath or shower depending on the job requirements.

For instance, for customers who want to reduce the number of grout joints by embracing the large-format tile craze, you will want a mortar that meets ANSI A118.4 or A118.15 standards.  Premium-grade, single-component large and heavy tile mortars are designed to meet or exceed these requirements. The mortar is formulated for non-sag, non-slump application of oversized, hefty tiles. It forms an instant bond while providing extended open time to handle even larger gauged porcelain tile panels and slabs.

Having the right mortar isn’t everything, though. Following TCNA application specifications and the manufacturers’ instructions are essential to ensure your installations will last.  Installation practices such as spot bonding are unacceptable in any situation due to the tile weak spots it creates. And the voids created from spot bonding leave room for mold growth in wet applications. 


TILE 0622 Technical Focus Merkete 03 Grout

Photo courtesy of Sika


Grout and Get Out

Grouting should mean your project is nearing its end. In reality, it is where a number of issues can arise that will get you called back to the jobsite to remedy. Choosing the wrong grout for the wet environment or improperly mixing and applying the right grout will present problems almost immediately after the first few showers. For instance, standard cementitious grouts must be mixed with clean potable water to a specific ratio to cure properly. Overwatering or cleaning too soon can cause blotches, discoloration or efflorescence that may require additional products or strong solvents to fix. High-performance, ready-to-use grouts take much of the guesswork out of tiling showers and baths. 


Standards + Materials = Success

The standards we use today for bath and shower installations are the culmination of more than a millennium of practice and experience. The same can be said for the tile-setting materials currently on the market. By closely adhering to the time-honed standards and selecting products specifically designed to perform as needed in wet demanding environments, you can be sure that your bath and shower installations will provide ageless satisfaction for decades to come.