Photo courtesy of tile redi.


New home construction has slowed down substantially across the US. With it has gone most of the easy money many have enjoyed for years by just doing floor work in the residential sector. But, a good number of installers, those who are shower installation specialists have continued to enjoy a healthy backlog of jobs waiting for their talents. It is their higher skill level and ability to do jobs beyond the ordinary floor or backsplash that makes them specialists.

True today as it has been since I’ve been in the trade, a good floor tile installer does not make a good shower installer. Retailers seem to have a hard time grasping this concept. They assume because the installer’s work always looks great on the floor, then he certainly could do the same with a shower or tub. Installers know better - many cringe at the idea of having to enter such a foreign realm where the possible liability of water damage to a structure can cost thousands of dollars in uninsured damages. Floor and wall tile installation require a certain amount of skill and some very basic knowledge. Showers, mortar floors, and wet area installations on the other hand require a high degree of both skill and knowledge. Those that have the ability to float mortar on not only the floor but also the walls in wet areas are the rarest installation specialists of all. If you want continuous work at good profits, now may be a time to focus on learning more about the specialized area of wet installations.

There are proliferations of products being offered today that claim to be the “answer” to leak-free showers. While many are fine and very viable products, there is often too little information readily (keyword) available other than the typical sales pitch and information offered on the box, bucket, or bag. Showers being constructed today are increasingly complex and with it, the inherent risk of water damage increases. Having the advantage of personally working with many of the different waterproofing products available, 18 at last count in our warehouse, I can assure you, they all have their little nuances. Various liquids, sheets, and cement-based products each have their own very specific performance levels with variable installation requirements and working characteristics.  

Many liquid- and cement-based waterproofing products recommend pretreatment of corners and drains in waterproof applications.

Read the Literature

When researching products to consider for use, I would advise you to seek out the manufacturers printed literature rather than solely relying on a verbal representation. Thoroughly understand the requirements for performance and warranty offered.

Nobody seems to want to read. I can say this with authority because we receive calls daily from people who have the literature on hand, but want to know either where they can find the information in the literature or what it says. Published literature will provide you with the highest degree of accuracy and contains information thoroughly reviewed by the highest levels of authority in the company. If a problem arises, the printed literature will prevail, not the often-supplied verbal version.

If I seem overly sensitive to this it is probably due to some recent experiences on several large-scale projects where failure was imminent due to incorrect details the salesperson was supplying in wanting to secure a large order. No doubt the substantial cost of this failure would be borne by the less-than-perfect installer who did the less-than-perfect installation, which includes not only this author, but everyone who has ever touched a piece of tile. In both of these recent instances, it was the studied installer who pointed out the contrary nature of the detail, which was later verified, and they all lived happily ever after.

Many struggle with the concept of using foam products, as I did initially. This demonstration was in response to someone who alleged their body weight of 200 lbs. was causing 1” glass tile to come loose from a foam tray system. Despite repeatedly driving up the foam ramp with a car, the tile remained firmly in place.

Wet Areas 101

Let’s take a short look at some of the basics in shower building and wet areas 101. All water must go down the drain. Sounds exceptionally simple doesn’t it? I think so too, but if I were a betting man, odds are there is a lot of money to be made saying it doesn’t always work that way, some would go so far as to say seldom.

All too often water is left behind in the shower assembly courtesy of not just the tile installer but the plumber who improperly installed the shower pan, and in some local jurisdictions (I hope they are reading this), code officials who failed to enforce plumbing codes. Showers are water critical management systems. The typical shower sees more water in a month’s use than many climates receive in a year. To effectively manage this staggering amount of water, we need a number of things to happen.

First is the proper pitch under the waterproofing material directing it to the drain assembly. Most state and local codes are adapted from one of several national code writing organizations. All these organizations require that a pre-pitch of 1/4” per foot be used under the waterproofing material. This is probably the least enforced plumbing code item in the book when building conventional mortar base showers. Given the time and money it takes to create a pitch, coupled with the lack of enforcement by code officials, plumbers commonly ignore this code requirement when they install shower pan liners. Where tile installers are allowed to install the waterproofing material, code applies to their work as well. Assuming this requirement is met, we must have the proper type of drain assembly for this pre-pitch to be beneficial.

Conventional shower drains for mortar applications actually have two drainage areas - the top, which we’re familiar with; and weep holes at the bottom where the membrane clamps to the drain assembly. These holes must also be kept clear of mortar to function properly. In the case of large showers, you may even want to consider the use of a drainage mat over the top of the waterproof membrane. Even with the proper pitch and weep holes being kept accessible for drainage, there is a still a very large amount of water kept in the shower floor seeking a way out. This water must wick its way from the outside edge of the shower floor to where the drain is located. This is often only a few feet but in larger showers, it can be much more.

Drainage mats used over a conventional waterproof membrane can provide a path for the water to freely leave the systems soon as it passes through the depth of the mortar bed (a few inches) rather than length (measured in feet). This promotes a healthier environment not only for the floor but the bathroom itself by reducing the amount of humidity caused by retained water that would otherwise drain slowly from the floor. I think most of us have been in commercial environments where you could feel the humidity of large, exposed areas and showers. Using a drainage mat would be a great contribution to reducing that damp feeling.

There are an increasing amount of foam products entering the market. This system includes a pre-pitched base, curb, and drain assembly ready to receive waterproofing. These types of systems allow for faster installation of typical showers.

Waterproofing Products

Some of the more popular products of today are topically applied waterproofing products. With application of surface applied waterproofing materials in lieu of conventional waterproofing products, humidity is greatly reduced by less moisture retention in the system. These come in various forms such as liquid, cementious, and sheets. These products are applied directly to the surface to be tiled and therefore, in most but not all instances, only the surface to be tiled requires a drain slope. The degree of waterproofing provided by liquid and cementious systems is entirely dependent on what is known as film thickness.

With trowel-on systems, the trowel itself is used as a metering device to assure proper thickness. Typically the product is keyed into the substrate with the flat side of the trowel, combed with the notch side of the trowel, and then the ridges are flattened by combing once again with the flat side of the trowel. If you’re good with a trowel and have a smooth surface, this is a relatively simple task.

Most liquid systems (not all) require multiple coats because it takes a specific thickness or film coating of the product to be waterproof. Think of a raw wood board and the first coat of paint. It readily soaks into the wood. You know if you don’t put another coat on and it is exposed to moisture, it will rot. That is the same effect an inadequate film thickness has when liquids are used as a waterproofing material. With direct bond sheet products, the thickness is predetermined. However, they must be appropriately bonded and seamed to provide a leak proof surface.

The key issue on making these topically applied products work is the drain interface and corner reinforcement when required. With liquid systems, most provide detailed instructions on how to attach or bond their product to the typical two-stage drain assembly widely used by plumbers. Most often these recommendations involve the use a fabric or fiberglass reinforcing material at the bottom of the drain flange with several coats of liquid prior to bolting in the top of the drain assembly. This is most often where installation issues arise. When any of these surface systems are used, the drainpipe must be firmly anchored to the framing below, not by the waterproofing. Make sure you follow the specific recommendations for your product. There are several manufacturers on the market that make both a drain and a waterproofing product so you have a complete systems approach.

Still, other sheet and liquid systems are available with a special drain flashing, inside corners, and outside corners. There is a tremendous amount of variation in all products and their installation recommendations. Product availability of specialty items such as inside corners varies with each manufacturer, these pieces are not always easy to find. Check with your selected product manufacturer or distributor for a full line of their accessories.

Thus far, we have focused on shower floors. The best idea and typically a requirement when using any direct bond waterproofing application is to treat the entire shower to prevent any water that may be absorbed by the wall backing surface or go down behind the waterproof shower floor.

Waterproofing only the bottom half of the shower is very ineffective in managing moisture. More often than we care to see, we receive pictures of showers that have had partial waterproofing or inadequate film thickness and have failed. With few exceptions, backer boards are not waterproof. Those that are, still have special requirements for fasteners and edges to effect true waterproofing. Because many backer boards allow either water or vapor to pass, some recommend the use of a vapor membrane behind their panel in tub and shower applications. There are instances where this recommendation may be omitted when the entire unit is waterproofed. Building codes vary on this requirement and always prevail over manufacturer recommendations. While we have spent a great deal of time on the floor getting the water from the walls and floor down the drain and preventing damage that will otherwise occur, we should pay due attention to other areas of the shower.

When most plumbing codes were written, little consideration was given to seats, niches, and knee walls, which are relatively new additions to the shower scene. Curbs also remain an item of mystery for many. All these surfaces must have a pitch to direct the water to the floor drain, and must all be waterproofed as well. The new TCA Handbook for 2007 has added language to reflect this need and perhaps some day, code will also reflect this issue more appropriately. The failures of seats in particular are rampant.

Good shower installers are always in demand. Times may be a little tight now, but it won’t last long. Now is the time to take advantage of the many seminars and training opportunities available. Learn some new systems, make some new friends and join the ranks of the working and profitable.

Hope to see many of you at Coverings 2008 in Orlando this year expanding your horizons.