Traditional vs Bonded Waterproofing Showers
Unfortunately, due to sub par building requirements in the area, showers are not being built with longevity as a priority. Most tiled showers will do just fine under these requirements for at least two years, long enough to satisfy the warranty. After that, things start failing and this failure can be cosmetic or catastrophic. Let’s look at the reasons for failures and determine if a repair is the way to go.
Traditional Shower Pans
Traditionally built tiled shower pans have, as the name implies, been the standard for decades. The Tile Council of North America has several standards issued to dictate the proper methods and materials that are to be used to make this a permanent and reliable installation. However, these methods are rarely employed correctly. There are three problems that we see with almost every traditionally built pan that we remove.
Punctured Pan liner
In the traditional shower pan, the rubber pan liner is the only waterproofing, so it is critical that it be free of puncture. This rule is usually followed, except on the curb. In order to bond tile to the curb, cement board is nailed or screwed through the pan liner as it wraps over the curb. The stretchy rubber forms a tight seal around this fastener, for a few years, until the fastener rusts. Now there is a hole in the liner. As water under the tile is wicked up by the cement board and thinset mortar, it eventually finds the hold and molds and eventually rots whatever material is behind it.
Blocked weep holes
Traditionally built pans are also known as “water in water out” systems. This means that water does not exit the mortar bed under the tiled floor until it has first entered it and saturated it. The drain is specifically designed to provide an exit path for this water by presence of weep holes around its perimeter. These weep holes must be protected during the installation process. If they become blocked, then water in the saturated mortar bed has nowhere to go. This will accelerate the process of water finding holes in the pan liner at the perimeter of the pan or on the curb.
no pre-slope
In order for the pan liner and the weep holes to function as designed, the pan liner must be sloped to the drain. The is accomplished by first installing a sloped mortar bed, called a pre-slope, upon which the pan liner will sit. By this, as the top mortar bed saturates, water migrating downward will contact the sloped liner and work its way toward the weep holes and ultimately enter the drain. We have never seen a pre-slope in the field. The pan liner is always laid directly onto the subfloor. This turns the pan liner into a pool liner. Sometimes quarts of water sits permanently within the thick mortar bed, molding its contents and waiting for a nail or screw to rust out.
Bonded Waterproofing
All of the pitfalls associated with the traditional method are eliminated in a bonded waterproofing system. In addition to solving existing problems, this system adds benefits as well to make the shower a permanent, leak-free installation.
What is it
Bonded waterproofing is just that. It is waterproofing that you bond the tile to, directly. Instead of having a mortar bed that must saturate to function, the shower pan in a bonded waterproofing system has the waterproofing layer at the top. Water that penetrates the tile and grout (and it will), will immediately contact the waterproofing and then it must begin its journey toward the drain. This results in a pan that doesn’t retain water and can actually dry out between uses. This greatly reduces the mold possibilities and eliminates the leakage possibilities.
In this system, waterproofing extends all the way to the top of the tile structure. In a traditional system, there is rarely waterproofing on the walls. Tile is bonded directly to cement board, or oftentimes, drywall, which absorbs water and becomes a constant supply of moisture to mold growing being the tile and through the grout lines.
No fasteners
This system does not use fasteners (nails or screws) to install the waterproofing at the pan level. The pan is bonded directly to the floor with thinset mortar and the waterproofing membrane is bonded to the curb in the same way. Any fasteners used to install the waterproof wallboard to the studs are covered with more membrane. This results in a completely sealed system, from the top of the tile structure to the inside of the drain.
one system, one warranty
The traditional method uses multiple materials from multiple manufacturers. While they each come with their own product warranty, if the shower were to leak, each manufacturer is going to blame the other. Also, since they are only product warranties, should the homeowner succeed in filing a claim, they will only be paid the cost of replacing that material. The rest of the shower will come out of pocket.
With a bonded waterproofing system, one company owns the entire waterproof envelope. This means that if a leak were to happen, there’s no one else to point to. Schluter Systems, the manufacturer we at Charash Renovations prefer, warranties the shower for 10 years and will cover all components of the shower necessary to return the shower to its original function. They can make this warranty because, when installed correctly, it doesn’t fail.
Conclusion
As you can see, while traditional methods have been around a long time, when they are not done correctly, they are a setup for future failure. Multiple pitfalls exist to make this method a risky option when looking at potential contractors. At Charash Renovations, we only employ bonded waterproofing systems from Schluter Systems. You can rest confidently that your new shower will be function, beautiful, and leak free for generations. Or, at least until the design fads change.