Waterproofing

The most important part of shower construction and having a long lasting tile installation in a wet area is having proper waterproofing. Most of my shower construction relies on cementboard as being the tiling substrate for the wall. It is a very common misconception that cement board is waterproof. At best it can be called moisture resistant. That is to say that it will hold its structural integrity when exposed to water. However, it absorbs water at a very high percentage and will share the moisture it collects with whatever it is in contact with which is most likely framing.

Most porcelain tile has a water absorption rate of .5% and cement grout of around 10%. With a typical shower consuming at least 30 gallons of water, it is a guarantee that every time you use your shower, a substantial amount of water could be penetrating a non-waterproofed cementboard wall and being absorbed by studs. With the simple installation of a liquid applied waterproof membrane water will be 100% contained to only right beneath the surface of the tile and thinset. This adds up to a problem free shower that can completely dry between uses eliminating constant moisture. Showers constructed with a waterproof membrane are easier to keep clean and also will prevent cracks in the tile and susceptible grout lines as they have anti-fracture capabilities as well.

Bellow are some pre-tile installation pictures that show arguably, the most important part of a tile shower/bathroom.

 

Taped seams and screwholes ready for waterproofing.

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Walls recieve 2-3 coats of waterproofing.  After pan cures it will be waterproofed with 3 coats. 

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The last coat of pan waterproofing is dring in this picture. 

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Divot filled, 100% waterproof and ready for tile.

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Cementboard walls with 2 coats of redguard.  Waterproof Schluter Ditra was used as the floor substrate and all gaps and transitions on perimiter where sealed with 100% silicone.  The floor directly outside the shower can be a point of entry for water that is commonly overlooked.  Expessially on wood subfloors it is important to waterproof this area.

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