The NTCA, along with other leading tile installation trade associations, has released a position statement on thin porcelain tile. For more information on this statement, contact Bart Bettiga, NTCA executive director.
July 29, 2014
The official publication of the National Tile Contractors Association
The NTCA, along with other leading tile installation trade associations, has released a position statement on thin porcelain tile. For more information on this statement, contact Bart Bettiga, NTCA executive director.
Schluter-Systems’ new LEED Gold certified building is located just outside Reno, Nevada, and offers a picturesque view of mountain ranges on the horizon surrounded by terrain adjacent to the property with running streams and wild horses roaming freely on the land. In addition to the state-of-the-art facility, Schluter’s 97,500-sq.-ft. building is strategically located to offer increased service and faster delivery of products for their west coast distributors, dealers and contractors. It is also an ideal location for training and educational programs. The facility features a multitude of sensible and sustainable technologies to maximize energy efficiency, water usage and air quality.
Schluter recently hosted over 75 NTCA members for a training and educational seminar and tour of the facility. This was also an excellent opportunity for NTCA staff to update the attendees on association direction and strategic planning. The program included a complete presentation and tour of the building, which was in essence a hands-on research and development project for Schluter. Many of their products are showcased throughout the facility, offering a great example of how conventional building methods continue to evolve, and how tile and stone can be key elements in the successful implementation of sustainable systems that maximize energy efficiency.
Andy Acker, a leading trainer and presenter for Schluter-Systems, was the lead speaker and facilitator of the program, which consisted of two complete days of highly-engaged interaction. Former NTCA regional director and contractor John Trent, who is currently employed with Schluter, was instrumental in putting the program together and assisting in its development and promotion.
Topics discussed in the first day of the training seminar included lengthy interaction on the principle of uncoupling, covering details from the TCNA Handbook and thin-set installations. New product introductions included a preview of the new Ditra-Heat system, which was recently introduced to the trade. NTCA and Schluter leaders then held an open-forum discussion on installation practices and business strategies before heading out to a fabulous dinner.
Day Two consisted of the NTCA strategic planning update and a Schluter presentation on moisture management, including a lengthy discussion of waterproofing and examining details of both the TCNA and Schluter installation handbooks. Presentations on Schluter Kerdi Board and their innovative profiles as solutions to challenging installations completed the morning sessions. After lunch, all of the attendees broke into groups and moved into the training center locations, where several territory managers were ready with demonstrations of products in carefully-constructed modules. All of the groups had time to see the hands-on training demonstrations, ask questions and make comments, and move on to the next module.
The educational portion of the event concluded with presentations by Schluter leaders offering a glimpse into the future, sharing some strategies of products currently being considered for development. Schluter also shared their position on supporting Certification through the CTEF programs, and pledged to support the ACT Certifications currently being offered.
Many of the attendees stayed an additional day to go skiing, snowboarding and snowmobiling in the beautiful mountains located near Lake Tahoe. By all accounts, those that stayed the extra day were treated to a memorable experience. Schluter-Systems and NTCA leaders agreed that future meetings of this nature would continue to provide value to our members.
Many end users don’t want movement joints because they think they are distractive and ruin the appearance of their tile installation. So why should tile installers make sure that movement joints are installed in all of their tile installations?
The short answer is because industry standards say that all tile installations must have movement joints. If you don’t install movement joints, and there is some problem with the tile installation, then the fingers will be pointing your way and you will be held responsible even if the problem isn’t directly related to the lack of movement joints. Lack of movement joints can be a contributing factor to many different types of tile failures, so it’s not worth the risk to exclude them from your installations.
All tile and stone assemblies move in one way or another, whether due to thermal movement, moisture movement, shrinkage, freezing, or dynamic structural movements. To ensure a long-lasting installation, it’s important for architects to specify and provide the requirements for movement-joint design and placement, and to specify the correct type of sealant (caulking) for filling those joints. When there isn’t an architect – and the tile installer is determining how to install the tile – then it becomes the tile installer’s responsibility to specify and install the movement joints or to find someone else to specify them.
“Movement joint” is a general term used for all types of joints seen in construction materials that control and allow movement. Most commonly we refer to these joints as either “expansion joints” or “control joints,” but there are various categories of movement joints. Generally they contain an appropriate pliable sealant for the intended application that is often referred to as a soft joint. Movement joints allow for the material in which they are placed to move without restraint, and they control where the movement manifests, avoiding random cracking in finish materials. An example would be the joints or separations in a concrete sidewalk. If there were no movement joints in the concrete sidewalk, then it would crack at some random point as it is subjected to shrinkage (contraction) as it cures, or subjected to expansion when it is exposed to moisture or heat, and then contraction again as it dries and cools.
I have seen tile floors without adequate movement joints where a portion of the floor was literally tented (debonded and raised) several inches off its substrate during the heat of the day, but laid flat at night when it cooled down. To see how small horizontal movements can result in exponentially larger vertical movements, take a 48’ (1219 mm) metal ruler and lay it on a horizontal surface. Restrain one end of the ruler and move the other end toward the center 1/8” (3.2 mm), and you will see a 2” (51 mm) rise at the apex of the ruler. In effect, this is what happens to tile floors when they tent. They are constrained at their perimeters with no movement relief and the tile expands.
The Tile Council of North America (TCNA) provides general movement joint guidelines for tile and stone applications in its TCNA Handbook for Ceramic, Glass, and Stone Tile Installation. The guidelines are listed under EJ171 Movement Joint Guidelines for Ceramic, Glass, and Stone section. When there isn’t an architect on the job then the tile installer should refer to these standards to determine where to install movement joints. If there is an architect and they haven’t specified movement joints, then the tile installer should submit an RFI (request for information) to ask for the movement-joint layout and design.
The general rule is that movement joints should be placed at the perimeters of tile installations and at all transitions of planes or transitions to different materials, as well as within the field of tile. Inside and outside vertical joints on framed walls should have movement joints and should not be hard-grouted. Bathtub or shower receptor to wall transitions should have a movement joint. In wet areas, movement joints are important not only to control movement, but they act as a water-stop at those transitions, providing another layer of protection against potentially costly water damages.
TCNA EJ171 states that movement joints for interior applications should be placed at least every 20’ to 25’ in each direction unless the tile work is exposed to direct sunlight or moisture. In that case, movement joints should be placed at least every 8’ to 12’ in each direction – the same for exterior applications.
EJ171 states that all underlying movement joints in the substrate need to continue through the tile assembly. This means that in addition to honoring the substrate movement joints, the tile assembly needs additional movement joints within its assembly. If there is a mortar bed over the substrate, then the movement joint has to be continuous through it to the tile surface, which is considered an expansion joint. If the tile is being bonded directly to the substrate, and there is no substrate movement joint continuing up from beneath, then it is called a generic movement joint. The generic movement joints are often the same width as the grout joints if they were designed to work at that width. The movement joint widths within the tile work should never be narrower than the substrate joint on which it is placed.
Some manufacturers of ANSI A118.12 crack-isolation membranes allow their membrane to cover non-structural movement joints (joints that only move horizontally, but without any vertical displacement) such as saw-cut or cold-control joints, even though TCNA does not recommend it. Structural expansion joints can never be covered with membranes, since the vertical displacement cannot be mitigated with a crack-isolation membrane. Crack-isolation membrane manufacturers require that movement joints are installed within the tile assembly installed over their membrane. Some manufacturers allow the movement joints to not line up exactly over the substrate control joints. Each manufacturer of crack-isolation membranes may have different recommendations and limitations, so it is always important to follow manufacturers’ instructions.
TCNA F125-Partial and F125-Full Crack Isolation Membrane details provide guidelines for isolating non-structural cracks with an ANSI A118.12 crack-isolation membrane. This detail recommends that a movement joint be placed at one or both ends of the tile, parallel to the crack which is bridging the underlying shrinkage crack or non-structural control joint, as recommended by the membrane manufacturer.
Sealants for soft joints
The type of sealant (caulking) used to fill movement joints is critical to the success of the tile installation. TCNA EJ171 states that an appropriate ASTM C920 sealant must be used to fill movement joints of all types. An ASTM C920 sealant includes high-quality silicone, urethanes, and polysulfide sealants. These types of sealants are normally rated as highly weather resistant with high-elongation properties, and high-adhesion characteristics that come with 20-year commercial warranties. Too often we find installers using some type of acrylic, latex, or siliconized sealant, because they are easier to work with, but these sealants have very low performance values and basically no warranty.
Different sealants have different physical properties and performance capabilities. EJ171 provides guidelines and the nomenclature for determining the appropriate Type, Grade, Class and Use sealant for the intended application. For instance, some sealants are not suitable for foot or vehicle traffic, so you must use a “Use T” sealant for those applications. A traffic sealant should have a Shore A Hardness of 35 or greater, which is critical because otherwise it would be dangerous to those who wear high heels. Some sealants can’t be used in a submerged application and some can’t be subjected to certain chemicals. Not all ASTM C920 sealants are compatible with natural stone and could cause the stone to stain. Some sealants require the surfaces to be primed after cleaning the joints and prior to installing the sealant.
Movement joint aesthetics
Movement joints are a necessary part of tile and stone installations and can even accentuate design features, rendering the joints unnoticeable, when specifiers take the time to design the movement joints into the installation.
Manufacturers of one-part silicone sealants have a broad range of colors available; custom colors are generally available to match the grout. Two-part urethane sealants can be mixed on the job by experienced sealant installers and can easily match the color of the tile grout. Movement joints placed more frequently in the installation can be narrower to match the width of the grout, also making them less noticeable. If your tile pattern has staggered joints, you can use the staggered-grout joint (referred to as a saw-tooth joints or zipper joints) as a generic movement joint to make it less noticeable. When done well, movements joints are not noticeable and can enhance the features of the installation.
All tile and stone assemblies move in one way or the other, whether due to thermal movement, moisture movement, shrinkage, freezing, or dynamic structural movement. To ensure a long-lasting installation, install movement joints and use the correct type of sealant (caulking) for filling those joints. The key to a successful tile and stone installation is to follow industry standards.
Donato Pompo, CTC, CSI, CDT, MBA, is the founder of Ceramic Tile and Stone Consultants (CTaSC), and of the University of Ceramic Tile and Stone (UofCTS). He has more than 35 years of experience in the ceramic tile and stone industry from installation to distribution to manufacturing of installation products. Pompo provides services in forensic investigations, quality control (QC) services for products and installation methods, training programs, testing, and onsite quality control inspection services. He received the 2012 Construction Specifier magazine Article of the Year Award. Pompo can be reached at [email protected]
Glass tile continues to grow in popularity for both aesthetic and functional reasons. It provides an elegant, upscale look, and its composition makes it easy to clean and maintain. Because it can contain recycled glass, glass tile is also a sensible choice where sustainability is a concern.
However, the same attributes that benefit the end user of glass tile can also challenge its installer. For example, its imperviousness makes it ideal for wet areas like pools, showers and backsplashes, but also makes it difficult to bond. The translucence of some glass tile gives it a highly desirable appearance, but requires that the installer take extra care to create a uniform look when applying mortar and grout. To help the end user reap the benefits of glass tile, here are some proven installation strategies.
Mind the mounting
If glass mosaic tiles are specified, keep in mind that they are often pre-assembled into sheets with some type of mounting material. Before installing back-mounted mosaic glass tile in wet or submerged applications, check with the glass tile manufacturer to ensure the back mounting is suitable for wet areas. The adhesive used to bond the tiles to the mounting material may be water sensitive, resulting in bond issues in wet environments.
Mortars: bond and color
For any glass tile installation, you will need to address potential bond problems with your mortar selection. Glass tile’s lack of porosity requires the use of a latex-modified thin-set mortar, but not all modified mortars are suitable for glass tile. Some manufacturers have specific mortars designed for use with glass tiles.
With translucent tile, mortar color matters. White mortars provide a bright, consistent backing for translucent or transparent glass tile. They also minimize the effects of high alkalinity found in gray mortars that can result in glass tile discoloration and loss of bond strength.
However, the TEC® brand of setting materials offers additional aesthetic and functional options for bonding glass tile. To install glass tile, you may use TEC® AccuColor® Unsanded Grout (white cement-based colors only) mixed with XtraFlex™ Acrylic Mortar Additive. AccuColor® Unsanded Grout comes in a variety of white cement-based colors, which can enhance the final appearance of clear or translucent tile. Use of the mortar additive, rather than water, for mixing produces extremely high bond strengths.
Mastic is typically not recommended for glass tile. However, if the glass tile is pre-bonded to a colored backing, mastic may be the best option, because mortar can cause degradation of these backings. In dry areas, mastic is the preferred setting material for these types of tiles.
Room to move
Expansion joints also contribute to successful long-term installations of glass tile. Glass tile has a high level of expansion and contraction. Proper placement of expansion joints prevents the development of resulting stresses that disrupt the bond. For example, problems have occurred when dark glass tiles were installed on exterior walls without any expansion joints. When subjected to direct sunlight, the dark glass warmed and expanded. Without flexible expansion joints to accommodate the movement, the tile lost bond and “tented” up off the substrate. For recommendations regarding expansion joints, refer to Installation Method EJ171 in the TCNA Handbook or ANSI Specification A108.01, Sections 3.7 through 126.96.36.199.1.
Grout is an equally important consideration for a successful glass tile installation and requires consultation with glass tile and setting material manufacturers. Some glass tile can be susceptible to surface scratching when installed with sanded grouts and therefore requires the use of unsanded grout. Other glass tiles are compatible with sanded grouts. The same holds true of epoxy grout: some glass tile manufacturers recommend installing with it and some do not. In addition to traditional cement and epoxy grouts, some grouts, like TEC® Design FX™, are specifically formulated to be functionally compatible with and enhance the appearance of glass tile.
As you can see, there are some aspects of glass tile installations that are universal and some that vary by manufacturer, and even product line. Pre-installation communication with your suppliers and/or manufacturers is necessary to overcome these complexities, ensure successful installations and minimize callbacks.
TEC®, AccuColor®, XtraFlex™, and Design FX™ are trademarks of H.B. Fuller Construction Products Inc.
I just returned from the International Surface West event in Las Vegas. It was clearly evident that all the organizations that represent the floor-covering industry are emphasizing the importance of quality installation as an essential component to the growth of their respective industries. Throughout the show floor, you could find training seminars, live demonstrations, and certification testing taking place. This is a really good thing to see.
As a leader in the tile industry, I want to point out something that I think is very important about the word CERTIFICATION. It can be used in a variety of ways, and the tile industry needs to address this word immediately, so that we understand the difference as it relates to who is qualified to do what type of work in commercial and residential installations.
There are training programs currently being offered by some organizations that are entry-level relating to installing tile. At the end of the training session, “certifications” are given that the installer has successfully completed this program. There are also proprietary manufacturer training programs and online, knowledge-based seminars that offer “certification” for completing the course.
I want to be very clear in my point here. These are great things to see happen. Anyone who is offering training and increasing knowledge for the sale or installation of tile and stone is contributing to our industry growth.
All “certifications” are not created equally
But – and this is a big but – if these programs are marketed in the incorrect way, then all the good they have done is quickly swept away. This is, in fact, dangerous for our industry.
This is why the tile industry has taken a strong stance on the word CERTIFICATION. This is why we have written clear language related to qualified labor in the TCNA Handbook and in Master Specifications. We have to differentiate the installers that are truly qualified from those who are not.
The ONLY OFFICIAL certification currently being recognized by the tile industry – in accordance with standards set out by the tile industry – are the CTEF Certified Tile Installer (CTI) certification and the Advanced Certifications for Tile Installers (ACT) Program. The language is clear. In addition to these two certifications, we recognize Department of Labor-approved apprenticeship programs as a way to qualify installers as well.
Why is tile so different and why are we so serious about this? For one thing, tile installations are often designed to be permanent, often installed in wet areas, and at times with other living space underneath the installation. It is very expensive to replace, and other products have to be moved and can be damaged when replacement has to take place.
Tile and stone comes in different sizes, shapes, and formats, is extremely challenging, and not forgiving in regard to installation. It needs to be looked at differently than other floor coverings when considering who is qualified to perform the work.
Our own industry recognized that even a rigorous certification test like the CTI exam the CTEF offers was not enough. That is why we partnered with all the leading tile industry trade associations to develop the ACT program – so that we go further into specific skills such as shower pans, mudwork, waterproofing and crack isolation, and large-format tile. We will be adding grouting applications and thin-tile installation very soon.
Invest in industry-recognized certifications: CTI and ACT
To every tile installation contractor who reads TileLetter regularly I am telling you today: contact the CTEF or your local union representatives to discuss the official, tile-industry-recognized CTI or ACT programs. If you are already a CTI, you need to make plans to become ACT-certified. You need to differentiate yourself from the competition. And you definitely need to understand the difference between these certifications and others that are being offered and rewarded out there.
I can’t think of anything more damaging in our industry than a beginning tile installer getting hired instead of a more qualified tile contractor because they have a piece of paper that says they are “certified” in a program that the tile industry doesn’t recognize. How would a consumer or builder know the difference? They wouldn’t! You need to get officially certified in a program our industry supports and recognizes, and you need to understand how to explain that to your customer.
Certification is here to stay. The specifications are starting to call for it. Our industry needs it; the quality tile contractors need it as well. Contact us immediately to discuss how we can help you set yourself apart from the competition.
Exterior decks and balconies, and interior showers and bathrooms have historically been problematic areas for the installation of ceramic tile, glass tile, stone tile and other stone products. Typically problems are due to installer error, such as not using appropriate materials for those applications, or not having clear enough specifications. In each case it is the result of not following industry standards. Exploration into the intricacies of exterior decks and balconies can be an entire article in itself, but for this story, we will focus on interior showers and bathrooms.
Industry standards are created by industry consensus groups consisting of installers, producers, and industry experts through organizations such as ANSI (American National Standards Institute), TCNA (Tile Council of North America), ASTM (America Society for Testing and Materials) or ICC (International Code Council). These consensus group members combine their many years of experience with science to establish standards so problems and failures can be avoided and not repeated. Thus if standards are not followed then known potential problems can’t be avoided.
As a forensic investigator for over 11 years, I have investigated many failed interior showers and bathrooms. I have found that the common denominators to tile and stone failures in these applications were the lack of proper slope, plugged weep holes, and inadequate flashing to contain or manage the water that resulted in various types of damages.
Managing water volume
First, consider the volume of water that showers are subjected to on a daily basis. Since these areas are likely to be subjected to more water than a typical roof is subjected to annually, it is imperative that extra care and attention are spent on specifying and constructing them. This is accomplished by properly managing the water so it is controlled and safely evacuated from those areas.
Lack of adequate slope is a common problem in interior wet horizontal applications such as shower floors, shelves and seats. It is very clear in the tile and stone industry standards, as well as in the Uniform Plumbing Code (UPC), and in the IRC (International Residential Code) or IBC (International Building Code) building codes, that the slope to drain, or away from the building, should be a minimum 2% slope. That calculates to 1/4” per foot (6 mm per 305 mm). UPC says the slope to drain in a shower must be a minimum of 1/4” per foot (6 mm per 305 mm), but not more than 1/2” per foot (13 mm per 305 mm).
Not only is it important for that slope to drain to be at the surface of the tile or stone, but it is critical that the minimum 1/4” per foot (6 mm per 305 mm) slope to drain is at the surface of the waterproof membrane or drain plane. Drains come in two sections. Where the drain clamps down on the waterproof membrane below the surface of the tile assembly, there are weep holes in the drain assembly, so that any water that migrates to the waterproof membrane can then evacuate into the drain through the weep holes.
Problem #1: Improper slope to the drain
There are three common problems that we run into. First, the waterproof membrane is not properly sloped to the drain. In a shower this can result in the tile mortar bed staying constantly damp, which creates a musky odor in the room, or it may cause a stone or tile floor to look wet. Excessive moisture might result in the stone spalling (deteriorating) and/or staining. Sometimes we find that the waterproof membrane is flat or even negatively sloped away from the drain, or that there are low spots on the membrane surface where water collects.
Problem #2: Plugged weep holes
The second common problem is drains with plugged weep holes. Industry standards state that the weep holes are to be covered with pea gravel or with a plastic weep hole protector to make sure the weep holes stay open. Often this weep hole protection is left out, and mortar is placed over the weep holes, plugging them. Thus, if the waterproof membrane is properly sloped to drain, the water cannot escape into the drain. Again, this can result in the tile mortar bed staying constantly damp, which results in the musky odor in the room, a wet-looking floor or stone spalling or staining.
The term “spalling” refers to the deterioration of the surface of a stone. It is the symptom of a stone being subjected to excessive moisture over time. Spalling is typically caused by moisture migrating from the stone’s underlying substrate up through the stone to its surface where the moisture evaporates. As the moisture travels from under the stone through the cementitious materials, and through the stone itself, the moisture picks up various minerals (salts) which dissolve in the moisture. When the moisture reaches the surface of the stone it evaporates and the minerals precipitate into a solid again. This expansion or crystallization of the mineral, referred to as efflorescence, causes the surface of stones to deteriorate to some degree.
Whether it is a shower or an exterior deck or balcony, the waterproof membrane surface must be sloped to drain or away from the building. Shower pans or receptors are supposed to have a pre-sloped mortar bed installed over the base substrate before installing the waterproof membrane. The pre-slope needs to have a minimum slope of 1/4” per foot (6 mm per 305 mm).
That brings up the third common problem that we find in showers: waterproofing or vapor retarders that are not complete or continuous. They tend to lack flashing at transition areas. Considering the potential collateral damages a defective balcony can develop, it is important to construct it like a big shower pan. Assuming that the deck has been properly pre-sloped, the waterproof membrane must continue, or be flashed, up the wall at least 3″ (76 mm) above any thresholds to prevent water from causing any potential collateral damages. All seams, penetrations and transitions must be properly waterproofed, flashed and sealed with a sealant. These are the areas that are most vulnerable to having problems, so they need to be given the extra attention to ensure they are installed correctly. The waterproof membrane should never be penetrated, unless it is unavoidable, and then the penetration has to be properly flashed and sealed with the appropriate sealants to ensure it will never leak.
Often we find that decks are sloped to their outer edge without any type of gutter or drain. The water drains over the side of the balcony and eventually results in staining along the siding, or staining and spalling the stone if there is stone siding. The latest trend is to use trench or linear drains that work very well and can be installed at the perimeters of decks or showers.
So how can a tile installer make sure that showers are given the attention they need to avoid failures? It is the same old answer. Follow industry standards and manufacturers’ directions. It doesn’t matter who is at fault when there is a problem; everyone ends up paying – either in time to defend themselves, money to fix the problem or with their reputation. So it is in everyone’s best interest to make sure that tile and stone installations are done properly. (Editor note: please visit www.tileletter.com for the full text of this story, which also addresses exterior installations).
Ceramic Tile Consultant, Donato Pompo, CTC, CSI, CDT, MBA, is the founder of Ceramic Tile and Stone Consultants (CTaSC), and of the University of Ceramic Tile and Stone (UofCTS). Donato has over 35 years of varied experience in the ceramic tile and stone industry. CTaSC provides services in Forensic Investigations, Quality Control Services for products and installation methods to include writing specifications, training programs, testing, and on-site quality control inspection services. CTaSC is a professional consulting business comprised of accomplished ceramic tile consultants, stone consultants, ceramic tile and stone installers, architects, engineers, general contractors, construction scientists and other industry specialists and experts conveniently located throughout the US and Canada. You can reach Donato by visiting the company website at www.CTaSC.com, emailing [email protected] or calling 866-669-1550.
By Donato Pompo, CTC CSI CDT MBA, Ceramic Tile and Stone Consultants (CTaSC), University of Ceramic Tile and Stone (UofCTS).
(Editor note: a condensed version of this story appears in the January 2014 issue of TileLetter)
Exterior decks and balconies, and interior showers and bathrooms have historically been problematic areas for the installation of ceramic tile, glass tile, stone tile and other stone products. Typically problems are due to installer error, not using appropriate materials for those applications, or not having clear enough specifications. In each case it is the result of not following industry standards.
Importance of industry standards
Industry standards are created by industry consensus groups consisting of installers, producers, and industry experts through organizations such as ANSI (American National Standards Institute), TCNA (Tile Council of North America), ASTM (America Society for Testing and Materials) or ICC (International Code Council). These consensus-group members combine their many years of experience with science to establish standards so problems and failures can be avoided and not repeated. Thus if standards are not followed then known potential problems can’t be avoided.
culprit in tile and stone failures
In the last ten years or so, since the demand and use of tile and natural stone has grown so dramatically, there have been a lot more failures caused by tile and stone being subjected to excessive moisture. Obviously tile and stone are very resistant to problems as indicated by the fact that there are tile and stone installations that are still standing and functional after thousands of years of use and exposure to various weathering conditions.
But when a number of things are done incorrectly in a tile and stone installation, particularly where water is involved, it can lead to extreme damages that can cause visually aesthetic damages and substantial collateral damages of adjacent materials, which can significantly reduce the functional life of the tile or stone application.
On the other hand, if tile and stone are installed correctly, per industry standards and product manufacturer’s directions, these products can provide trouble-free installations that can provide many years of pleasing aesthetics and successful performance that will be our legacy to future generations.
In over 11 years as a forensic investigator, I have found the common denominators to failed exterior decks and balconies, interior showers and bathrooms are the lack of proper slope, plugged weep holes, and inadequate flashing to contain or manage the water , resulting in various types of damages.
First, consider that exterior decks and balconies are often not only subjected to water directly from rain, but often water is channeled through drains and scuppers to these areas further subjecting them to higher volumes of water. Plus these areas are often washed down regularly so they are further subjected to large volumes of water.
Consider the volume of water that showers are subjected to annually. If one person takes a 12-minute shower each day in an average size shower with reasonable water pressure and using an appropriate shower head, the amount of water it is subjected to is equivalent to a roof being subjected to about 1,000 inches of rain water per year. Since these areas are likely to be subjected to more water than a typical roof is subjected to annually, it is imperative that extra care and attention is spent on specifying and constructing them. This is accomplished by properly managing the water so it is controlled and safely evacuated from those areas.
Be savvy about slope
Lack of adequate slope is a common problem in both exterior horizontal applications as well as interior wet horizontal applications such as shower floors, shelves and seats. It is very clear in the tile and stone industry standards, as well as in the Uniform Plumbing Code (UPC), and in the IRC (International Residential Code) or IBC (International Building Code) building codes, that the slope to drain, or away from the building, should be a minimum 2% slope. That calculates to 1/4″ per foot (6 mm per 305 mm). UPC says the slope to drain in a shower must be a minimum of 1/4″ per foot (6 mm per 305 mm), but not more than 1/2″ per foot (13 mm per 305 mm).
Not only is it important for that slope to drain to be at the surface of the tile or stone, but it is critical that the minimum 1/4″ per foot (6 mm per 305 mm) slope to drain is at the surface of the waterproof membrane.
Drains come in two sections. Where the drain clamps down on the waterproof membrane — below the surface of the tile assembly — there are weep holes in the drain assembly, so that any water that migrates to the waterproof membrane can then evacuate into the drain through the weep holes.
One of three common problems that we run into is first that the waterproof membrane is not properly sloped to the drain. In a shower this can result in the tile mortar bed staying constantly damp, which results in the room taking on a musky odor or it may cause a stone or tile floor to look wet, and the excessive moisture might result in the stone spalling (deteriorating) and/or staining. Sometimes we find that the waterproof membrane is flat or even negatively sloped away from the drain, or that there are low spots on the membrane surface where water collects. These same conditions can be found on an exterior deck or balcony. Obviously an exterior deck or interior commercial floor with multiple drains is a somewhat complex installation for the waterproof installer and the tile installer. In these cases, you will have transition areas that peak and slope in one direction or the other towards the respective drain. So it is critical to make sure that the drains and slopes are properly laid out to allow for all the water that reaches the membrane to readily evacuate through the drain weep holes. Even when there are drainage mats installed on top of the waterproof membranes to facilitate the evacuation of water from the mortar bed into the drain, if the waterproof membrane is not properly sloped it can result in expensive problems.