Tech Talk – July 2016

TEC-sponsorSuccessful glass tile installation for pools

By Tom Domenici, area technical manager, H.B. Fuller Construction Products

tech-01Once you’ve seen a swimming pool finished with glass mosaic tiles, their popularity for both residential and commercial installations is immediately appreciated. Because they reflect natural light, glass mosaic tiles can give swimming pools a lustrous, shimmering appearance. They’re available in almost any color, size and pattern imaginable.

Here are the seven main components of a beautiful and long-lasting glass tile pool installation.

Porcelain or glass tile is the right choice for saline pools. Use a premium mortar that can withstand salt exposure and a chemical-resistant grout.

Porcelain or glass tile is the right choice for saline pools. Use a premium mortar that can withstand salt exposure and a chemical-resistant grout.

1. Choosing tile

Today, mosaic glass tile manufacturers often create sheets of tile by bonding the individual tiles to a paper or plastic facing or by adhering the backs of the tile to an open-weave mesh that allows the mortar to come into contact with the tile backs. Using this type of tile can help save time. However, if a water-soluble adhesive was used to bond the mosaic tiles to the mesh backing, that adhesive could re-emulsify once submerged. To avoid this, confirm with the tile manufacturer that the mosaic glass tile itself, and the sheet mounting method used, are suitable for pool installations in their environment, whether interior or exterior. Or use paper-faced tiles, which provide an unimpeded surface on the tile back for bonding.

2. Cutting tile

If the tile layout requires partial sheets, simply score the plastic sheeting, mesh or paper holding the tiles together with a utility knife as needed. If you need to cut the tiles themselves, use specialized glass mosaic tile cutting tools, as other cutters may shatter the small tiles.

The Robert D. Love Downtown YMCA in Wichita, Kan., contains more than 50,000 sq. ft. of mosaic and large-format tile.

The Robert D. Love Downtown YMCA in Wichita, Kan., contains more than 50,000 sq. ft. of mosaic and large-format tile.

3. Waterproofing pools

Over the primary waterproof membrane on the shell of the pool (per TCNA P602-16), you must provide a secondary waterproofing and crack isolation membrane.

Before applying the secondary membrane, smooth the substrate with a deep patch and patch additive that’s fast-setting, or a bonded mortar bed. Then clean the substrate of all contaminants, residues and dirt. Pre-fill all concrete cracks up to 1/8” wide. Treat all control joints, substrate joints, field seams and corners; anywhere vertical surfaces meet horizontal surfaces, such as curbs, bench seats and columns; anywhere dissimilar materials meet, such as drains and expansion/control joints.

Then, apply the waterproofing membrane. Install it just below the tile to help prevent water from leaking into the mortar bed and to help prevent problems associated with saturation and moisture expansion. For an efficient installation, use a membrane that allows for the direct bonding of tile. After the membrane is properly cured, test for leaks.

 

NTCA Five Star Contractor Fox Ceramic Tile of St. Marys, Kan., turned to TEC® products to aid with fast-paced tile installation in a variety of challenging environments.

NTCA Five Star Contractor Fox Ceramic Tile of St. Marys, Kan., turned to TEC® products to aid with fast-paced tile installation in a variety of challenging environments.

4. Setting tiles

 

Glass mosaic pool tile applications require polymer-modified mortars that are suitable for submerged installations. Keep in mind the mortar’s color can affect the appearance of clear or translucent glass mosaics. White mortars typically produce the most pleasing and consistent appearance – allowing glass tile to maintain its natural luminosity. Similarly, mortar ridges may be visible through clear or translucent tiles. Therefore, after troweling the mortar, use the flat side of the trowel to flatten mortar ridges before setting tile. Back-butter the tile to achieve a uniform appearance and proper coverage.

5. Grouting tile

Only certain grouts are appropriate for submerged areas. Consider a high-performance, ready-to-use grout or an advanced-performance cementitious grout, that can be used in submerged areas for glass tile installation. Saltwater pools require a grout that can be fully submersible and has chemical resistance, such as an epoxy grout. Proper pool water chemistry is essential for the future condition of the tile and grout. Use an appropriate flexible caulk joint, in place of grout, for predetermined movement joints in the tile installation.

The 110,000 sq. ft. LEED®-Certified facility features large -format porcelain tile on its lobby floor, ceramic and porcelain tiles throughout the building, and porcelain mosaics in its pools, whirlpool and steam room. 

The 110,000 sq. ft. LEED®-Certified facility features large -format porcelain tile on its lobby floor, ceramic and porcelain tiles throughout the building, and porcelain mosaics in its pools, whirlpool and steam room.

6. Wait time

Advise your customer to refer to the grout and mortar manufacturer wait time before filling the pool with water to allow the tile grout and mortar to fully cure before use in submerged areas.

7. Maintaining tile

In general, glass mosaic tile is very low maintenance. It is naturally stain resistant, and the use of a high-quality grout will help the installation maintain its appearance. However, tile in even the cleanest pools will eventually accumulate calcium deposits and other residue.

Cleaning techniques will vary depending on the tile system and condition, but always do a small sample test area to determine the best procedure.

Regardless of the type of tile used, fun in the swimming pool begins with a successful tile installation. If you follow these simple steps and manufacturer instructions, your tile glass project will make a splash for a long time after your work is completed.

 

For this job, installer Fox Ceramic Tile used TEC® products to address each space’s unique demands, including time constraints and exposure to heat and harsh chemicals.

For this job, installer Fox Ceramic Tile used TEC® products to address each space’s unique demands, including time constraints and exposure to heat and harsh chemicals.

The TEC® brand is offered by H.B. Fuller Construction Products Inc. – a leading provider of technologically advanced construction materials and solutions to the commercial, industrial and residential construction industry. Headquartered in Aurora, Illinois, the company’s recognized and trusted brands – TEC®, CHAPCO®, Grout Boost®, Foster®, ProSpec® and others – are available through an extensive network of distributors and dealers, as well as home improvement retailers. For more information, visit www.hbfuller-cp.com.

 

Exterior porcelain rainscreen wall systems

june-tech-01By Rich Goldberg AIA, CSI, NCARB
Professional Consultants International, LLC and PROCON Consulting Architects, Inc.

In the first article on this subject, I provided an update on large-format porcelain tile panel technology, and its emerging use as a mechanically attached cladding panel in exterior rainscreen building façade construction. The overall technical concepts of rainscreen wall systems were also summarized. In this installment, I will focus on the detailed technical issues associated with this new technology, and the challenges to tile contractors who choose to grow their business with this emerging porcelain tile technology.

Training and re-tooling for tile contractors

The challenges for education, training and re-tooling are best examined by breaking down the three major components of porcelain panel rainscreen wall systems:

  • Porcelain panel
  • Structural support framework
  • Structural back-up wall and ancillary components
Fig. 1 Details of prefabricated porcelain panels.

Fig. 1 Details of prefabricated porcelain panels.

Porcelain panels – Most quality porcelain rainscreen systems utilize panels that are completely pre-fabricated and delivered ready to install (Figure 1). In our design practice, we avoid any manufacturer’s system that allows field fabrication of such precision wall systems. The cutting of each panel, many with unique and precise dimensions, and the precision required for drilling and setting mechanical anchors (Figure 2) dictates that the majority of porcelain panels be pre-fabricated under controlled factory conditions to deliver a high-quality, durable wall system.

Fig. 2 Precision attachment detail for lower portion of panel, allowing for expansion, contraction and structural movement.

Fig. 2 Precision attachment detail for lower portion of panel, allowing for expansion, contraction and structural movement.

Many tile contractors are already familiar with large-format thin tile (a.k.a. LTPT or “gauged large format porcelain tile”), and understand the specialty equipment and training necessary for proper delivery, handling and installation of such panels for interior walls and flooring. Depending on the size of porcelain panels used in exterior rainscreen walls, such equipment may also be necessary in addition to specialty hoisting sub-frames and lift equipment. Safe handling is especially critical, not only due to the expense of each panel, but in many cases due to the unique dimensions of each panel (you can’t just take another tile from the box!).

Structural support framework – as with the porcelain panels, the majority of the aluminum framework used to support the porcelain panels is typically proprietary and provided pre-fabricated by the manufacturer; we likewise avoid manufacturer’s systems that rely on stock framing components and allow contractors to construct solutions in the field that have not been engineered or vetted by performance testing in the laboratory.

Fig. 3 Tile contractor training session for aluminum framework and porcelain panel installation procedures.

Fig. 3 Tile contractor training session for aluminum framework and porcelain panel installation procedures.

The proper installation and alignment of the supporting framework is the most crucial aspect in the construction of porcelain panel rainscreen wall systems. This is a significant departure from the “brick (tile) and mortar” skills typical of the tile trades, and requires skill and training in metal framing procedures (Figure 3). Again, based on experience, I only recommend considering manufacturer’s systems that provide fully pre-engineered and pre-fabricated proprietary supporting framework.

Similar to the porcelain panels, capabilities to understand and manage both the engineered shop drawings and the architect’s detail drawings are critical, especially due to the interfaces with other building systems such as the alignment with windows and attachment to the underlying structural wall components.

Structural back-up wall and ancillary components – this is the most complex and project-specific aspect of porcelain panel rainscreen wall systems, but the least problematic sub-system for the tile contractor. Tile contractors need to focus education and training efforts on the following:

  • Types of structural back-up wall systems – metal stud/sheathing (most common), concrete masonry units, or concrete
  • Waterproofing – continuous AMV (air, moisture, vapor) membranes
  • Insulation – continuous rigid insulation (outboard of back-up wall)
  • Flashings and accessories – metal and sheet-membrane flashings, primarily at interfaces with other building systems (window sills, heads, roof copings, etc.)
Figures 4 and 5 - Installation of porcelain rainscreen panels in progress, revealing ventilated air cavity and air, moisture and vapor (AMV) barrier installed by others.  Note this project did not require any outboard continuous insulation.

Figures 4 and 5 – Installation of porcelain rainscreen panels in progress, revealing ventilated air cavity and air, moisture and vapor (AMV) barrier installed by others.  Note this project did not require any outboard continuous insulation.

june-tech-06On many projects, the manufacturer’s engineer would coordinate efforts to evaluate the architect’s details and provide engineering requirements for attachment of the supporting framework to the back-up wall. Similarly, on many projects, the installation of the AMV would be performed by a waterproofing contractor in advance of the rainscreen wall system (Figures 4 and 5), and the project may or may not require external continuous rigid insulation (Figure 5). However, the manufacturer of the wall system is not responsible for providing those materials. In some cases, though, general contractors prefer the sub-contractor responsible for the installation of the porcelain panel rainscreen wall system to also coordinate and install the AMV, insulation, and all flashings (Figure 6) for single source responsibility.

Fig. 6 Coordination of installation with base of wall flashing and interface with cast stone base specified to avoid snow removal damage at base of columns.

Fig. 6 Coordination of installation with base of wall flashing and interface with cast stone base specified to avoid snow removal damage at base of columns.

Shop fabrication and erection drawings – In our design practice, we find that the biggest challenge for tile contractors, aside from specialized equipment and training required for handling and installation of these systems, is developing the resources and capabilities to understand and manage the crucial role of shop fabrication and erection drawings. Most quality porcelain rainscreen system manufacturers provide for and supply engineered shop drawings in the cost of their system, so tile contractors only need to concentrate training / human resources required to effectively manage the process. This not only includes technical capabilities for interaction with the manufacturer, their engineers, and the building architects, but also the logistics required for panel delivery, marking and sequencing logistics. The allocation of human resource time alone is probably the most underestimated task required for successful porcelain panel rainscreen wall systems.

Needless to say, the above considerations are not only important to construction, but also to bidding these types of projects. In the last installment of this series, I will review a case study of both completed and in-progress projects to provide more insight into actual construction.

Richard P. Goldberg, AIA, CSI, NCARB is an architect and president of Professional Consultants International, LLC – Connecticut, and PROCON Consulting Architects, Inc. – Florida, both building design and construction consulting companies. Goldberg specializes in exterior building envelope systems, with sub-specialties in concrete, porcelain tile, natural & engineered stone, brick & concrete masonry, terrazzo, glass and waterproofing material applications.

Goldberg holds National Council of Architectural Registration Boards (NCARB) certification, and is a registered architect in the U.S. in multiple states, including Connecticut, New York, New Jersey and Florida. He is a professional member of the American Institute of Architects (AIA) and the Construction Specifications Institute (CSI). Goldberg participates in numerous tile industry standards committees, is a National Tile Contractor’s Association (NTCA) Recognized Industry Consultant, and received the prestigious NTCA Ring of Honor Award in 2014.

Tech Talk – May 2016

New product technology for trendy bathroom remodels

tec-logo

Sponsored By TEC

Bathroom remodels are sound investments for your customers. The rate of return tends to be 75% or more of the initial investment, which is significantly higher than many other home renovations. The 2016 Kitchen & Bath Design Trends Report predicts that “transitional” style will dominate this year’s bathrooms. Transitional style blends the traditional with the contemporary – balancing comfort with sophisticated, clean lines. You can provide your customers with transitional style by incorporating the following three types of products.

Preformed components

One way the 2016 Kitchen & Bath Trends Report suggests that transitional style can be achieved is with open storage and built-in shelving.

may-tech-01Preformed components – like niches – can provide unique open storage options for residential bathrooms. Preformed components are consistent and easy to install – great for fast multi-unit residential and hospitality installations. Look for products like TEC® Preformed Components that integrate seamlessly with existing surface prep solutions, mortar, tile and grout. For protection against mold and mildew, choose a product that comes coated with an IAPMO-approved, waterproof membrane that meets ANSI A118.10.

Preformed components are a great way for tile installers to add a design element that fits with today’s building trends.

In-floor heat innovations

In-floor heating systems also align with the transitional aesthetic. They serve as an “updated classic” for stone and tile floors. Moreover, they are a great selling point when listing a home. They may reduce heating costs, so they are a true investment – not simply a design trend.

Beyond adding value to the home, features like in-floor heat bring a feeling of luxury and warmth (literally) to bathrooms, to make getting up in the morning and getting home in the evening more relaxing. Although they are considered luxury items, improvements in efficiency have made them a more viable option for both building owners and contractors.
The right products can also cut down on the special ordering and lag time associated with radiant heat installations. For example, TEC™ In-Floor Heat is customizable on-site to fit any space – eliminating the lag time of special orders.

may-tech-02Advances in technology have made installations more efficient as well. In the past, in-floor heating installations had many cumbersome steps: the system had to be installed, anchored and encapsulated in a self-leveling underlayment. Today, some products – including TEC In-Floor Heat – can simply be embedded in mortar. Then, tile and stone can be installed directly over them.

Despite many advances, the wiring of installation systems can still present a challenge. Look for products that offer the simplest wiring available to avoid frustrating installations. The new TEC In-Floor Heat mat does not have coils or wires that require patterning—saving installation time. For all systems, be sure to use an electrical source with the correct voltage. If you hook up to a power source with the wrong voltage, it could damage the system.

Before adding radiant heat installation to your repertoire, check your local building codes. Some areas of the country require a licensed electrician to complete the installation, while others allow a tile contractor to do so. Almost all manufacturers recommend that a licensed electrician complete all electrical work.

may-tech-04In-floor heat systems are available à la carte or in kits. Since they are luxury items, look for products with touchscreen or programmable thermostats to provide the utmost convenience for your clients. Most thermostats can be set for either ambient room temperature or floor temperature.

Grout color trends

This year’s trends also include neutral colors – like greys, whites and beiges. Look for grouts that fit this description. Although beautiful, these light colors can also be more subject to unsightly staining than darker grouts. With that in mind, you should recommend stain-proof and mold- and mildew-resistant grouts, like TEC’s DesignFX® grout, shown below. These durable characteristics offer convenience to your customers and help preserve the aesthetic of their spaces.

may-tech-05New product innovations have made installing high-end bathrooms easier. By carefully selecting the most efficient products, you can make stylish bathroom remodels more convenient for your customers and more profitable for your business.

The TEC® brand is offered by H.B. Fuller Construction Products Inc. – a leading provider of technologically advanced construction materials and solutions to the commercial, industrial and residential construction industry. Headquartered in Aurora, Illinois, the company’s recognized and trusted brands – TEC®, CHAPCO®, Grout Boost®, Foster®, ProSpec® and others – are available through an extensive network of distributors and dealers, as well as home improvement retailers. For more information, visit www.hbfuller-cp.com.

Tech Talk – March 2016

TEC-sponsorTile and stone lippage:

Achieving acceptable tile lippage through quality tile and stone installations

Donato PBy Donato Pompo, CTC, CSI, CDT, MBA

Tile lippage is the vertical displacement between two adjacent tiles of a ceramic, glass, or stone tile installation. Excessive lippage can lead to a number of problems: the edge of the tile with excessive lippage can have a propensity to chip; furniture and appliances can get caught on edges and not slide easily across the floor; and most important today is that excessive tile lippage can be a safety hazard particularly to the elderly with our aging population. Tile lippage is an inherent characteristic of installed tile. It is not possible to eliminate it completely, but it can be minimized within reason.

(Ed. note: This is part two of a two part article. Part one appeared in the February issue of TileLetter, as the the Tech Talk feature.)

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Installation methods – The tile installation method used can help limit tile lippage, or it can contribute to excessive tile lippage. Adhering the tile directly to the substrate, particularly if it hasn’t been properly prepared to meet the industry requirements for flatness, can make it difficult to avoid tile lippage. On the other hand, installing tile in a fresh dry-pack mortar bed while it is still in a plastic stage can help compensate for the tile dimensional variations because the installer can embed the tile into the fresh mortar.

TT1-316

This looks like excessive lippage due to type of lighting and viewing angle, but it isn’t.

Installer skill and workmanship – Another factor that can contribute to excessive tile lippage is the lack of skill and workmanship by the tile installer. It is very important how skilled and conscientious the tile installer is, and the lack of those qualities can be a contributing factor to excessive tile lippage. If the installer isn’t experienced and skilled enough, or isn’t detail minded, then poor workmanship can cause or contribute to excessive tile lippage. It is important that qualified skilled tile installers who understand – and are current with – industry standards are used for tile and stone installations to help ensure a successful installation.

TT2-316

This is measuring lippage from previous photo, which shows that the ceramic tile lippage is less than 1.6 mm (1/16”) which is within standards.

Unavoidable lippage at drains – There are some applications where tile lippage to some degree is unavoidable. ANSI A108.02-2013-4.3.7 cautions that the lippage requirements don’t apply to tiled floors sloping to drains specifically when using tiles that are 6” x 6” (15 mm x 15 mm) and larger. The larger the tile surface area the greater the potential for tile lippage under these conditions. That is why you will often see tiles cut in half on a diagonal near drains that have sudden changes in slope. That doesn’t mean the installer can have extreme tile lippage; it still needs to be reasonable considering the conditions. Using the relatively-new trench or linear drains can be good solution to avoiding this problem.

Perceived excessive tile lippage – Another tile lippage problem is perceived excessive tile lippage, when in fact lippage is reasonable and within allowable standard tolerances. The culprit is lighting. Even the best of tile installations can have perceived excessive tile lippage when the light is shining on the tile surface at a certain angle relative to the viewing angle. This is more problematic with large rectangular tiles with narrow grout joints installed on walls, particularly if the tile is installed in a staggered pattern. Just look at some tile exterior veneers when the sun is directly shining on the tile surface and you will find certain angles where it looks like there is so much lippage that you can climb up the wall, when in fact it is within tolerance. On the other hand, under other viewing angles or lighting conditions you don’t see excessive tile lippage in these same installations.

TT3-3316

The perception of lippage is affected by the angle of the light falling upon the wall.

Optical illusion caused by lighting – Sometimes lighting causes shadowing at the grout joint, creating an optical illusion that there is excessive tile lippage. This can occur in interior and exterior applications with natural lighting or with artificial lighting. The TCNA Handbook warns that the use of wall-washer and cove-type lighting – where the lights are located either at the wall/ceiling interface, or mounted directly on the wall – may produce shadows and undesirable effects with tiles. Similar shadows are created from natural lighting on interior walls and floors when light shines from an angle through windows and doors. I have investigated a number of projects, both commercially and residentially, where there were complaints of alleged excessive tile lippage only to find out during our inspection that it was reasonable and within allowable industry tolerances. On the other hand, I have seen cases where there was indeed excessive lippage when the above referenced contributing factors were not properly managed.

How tile installers can avoid actual or perceived excessive lippage – It is the same old answer: follow industry standards, and don’t accept substrates that don’t meet industry standards, unless you are being paid to fix them.

It does not matter who is at fault when there is a problem – everyone ends up paying, either in time to defend themselves, money to fix the issue, or with their reputation. It is in everyone’s best interest to ensure tile installations are compliant to industry standards. The following paragraphs summarize the key steps that should be followed for tile and stone installations to avoid excessive tile lippage.

  1. Require a mock-up to be built that will become the standard upon approval for installation methods and for workmanship for aesthetic quality. It should include the specified lighting that the tile will be subjected to. If the client doesn’t allow for a mock-up, then after the first portion of the tile installation is completed, require that the client approve it and agree to use it as the standard for balance of the installation. This will help eliminate false expectations by the client, and if corrections are needed, it will be a lot less costly to fix it.
  2. Use good quality installation products because they typically perform better.
  3. Make sure your tile installers, both setters and helpers, are current with industry standards. They should be certified or verified to demonstrate they know and are current with industry thin-set standards (e.g. Certified Ceramic Tile Installers [CTI] through the Ceramic Tile Education Foundation [CTEF]; Tile Installer Thin-set Standards [ITS] Verification through the University of Ceramic Tile and Stone [UofCTS]).
  4. The stone should meet ASTM standards for its respective geological classification. Ceramic tile should meet ANSI A137.1 standards, and glass tile should meet ANSI A137.2 standards. Be sure to closely inspect the tile before installing it. If the warpage or sizing appears to be excessive either refuse to install it or get a written letter from the client approving the consequences. Then install a mock-up and get the client’s approval before proceeding.
  5. Considering the tile’s sizing and warpage tolerances, and the tile size and installation pattern, recommend a reasonable grout joint width to your client.
  6. Be sure to inform your client that lighting can cause the perception that there are excessive irregularities in the tile installation, when in fact the installation is consistent with industry tolerances. Tell them that light fixtures must be placed in a manner to avoid direct lighting on tile wall surfaces. You don’t need to tell them how to do it, as that is not your expertise. You can give them the language from our standards that warns of the problems that can occur if the lighting isn’t placed properly.
  7. Evaluate the substrate to make sure it meets ANSI requirements for flatness. If it doesn’t meet the ANSI standards then reject it and don’t proceed until it is corrected. Or you can correct the substrate for an additional fee. Cementitious self-leveling mortars or patching mortars can work well for repairing or preparing substrates for your tile installation. ANSI A108.02 states that if there are any obvious defects or conditions preventing a satisfactory tile installation, the installer is to notify the architect, general contractor, or other designated authority in writing, and is not to proceed until satisfactory conditions are provided that will allow for an acceptable installation.
  8. Use the TCNA Handbook for Ceramic, Glass, and Stone Tile Installation, the Marble Institute of America Dimension Design Manual, and the ANSI A108 standards as tools to persuade your clients of the need for you to follow the standards to ensure an acceptable tile installation. Being knowledgeable of these important standards will give you more credibility with your clients and will help you avoid costly problems.
  9. If the architect’s specification is ambiguous or if there is something wrong or missing, always submit an RFI (request for information) for clarification before proceeding with the work.
TT4-316

Viewing angle affects perception of lippage. Better lighting reduces the perception of lippage in this image – even though it’s the exact same wall with acceptable – but unsightly – lippage earlier in the story.

Conclusion

Excessive tile lippage can lead to damaged tile edges as various objects sliding on the floor hit these unsupported tile edges. Excessive tile lippage can cause trip and fall incidents, particularly for those elderly who tend to shuffle when they walk and use walkers. Even in commercial settings, tile lippage can be problematic and annoying as carts and other equipment clack as they run over tile edges.

Excessive tile lippage, or perceived excessive tile lippage, can be avoided by following the industry standards. Excessive tile lippage is typically due to a combination of improperly prepared substrates, improper installation methods, improper use of materials, and poor installer workmanship performance. Perceived excessive tile lippage is typically due to improper lighting design, overly narrow grout joints, and not following industry recommendations. Avoid the false expectations by the specifier or client by informing them of the potential issue in advance.

To avoid these problems, installers must be current with industry standards and follow those standards and the product manufacturers’ directions while installing the tile. Installers are mechanics with the skill level to provide quality workmanship, but they should not be expected to make architectural decisions – architects must give the installers the information and details they need to do their job correctly.

Many installers learn their skill on the job and do not have the opportunity to learn the industry standards. So it should be required that the tile installers are up to date with the current industry standards.

I have never investigated a tile or stone failure and found that all the industry standards and manufacturers’ instructions were followed. It is always the opposite. The failure is never due to one deficiency, but is generally due to many compounding deficiencies. Simply put, 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. Donato 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. Donato can be reached at [email protected].

Tech Talk – February 2016

tec-logoTile and stone lippage:

What is acceptable tile lippage and how do you avoid excessive tile lippage through quality tile and stone installations?

Donato PBy Donato Pompo, CTC, CSI, CDT, MBA

Tile lippage is the vertical displacement between two adjacent tiles of a ceramic, glass, or stone tile installation. Excessive lippage can lead to a number of problems: the edge of the tile with excessive lippage can have a propensity to chip; furniture and appliances can get caught on edges and not slide easily across the floor; and most important today is that excessive tile lippage can be a safety hazard particularly to the elderly with our aging population. Tile lippage is an inherent characteristic of installed tile. It is not possible to eliminate it completely, but it can be minimized within reason.

(Ed. note: This is part one of a two part article. Part two will appear in a future issue of TileLetter.)

Standards for tile lippage

There are industry standards for determining what is acceptable or excessive tile lippage. The American National Standards Institute (ANSI) A108.02-2013–4.3.7 for the installation of ceramic tile states that for grout joints less than 1/4” (6 mm) wide, the allowable lippage is 1/32” (1 mm) plus the inherent warpage of the tile. For grout joints that are 1/4” (6 mm) wide or wider, the allowable lippage is 1/16” (2 mm) plus the inherent warpage of the tile. There has been some confusion in the interpretation of this standard, which is discussed in detail later. The Marble Institute of America (MIA) simply says that there can be no more than 1/32” (1 mm) lippage for natural stone tile installations.

Substrate tolerances

1-TT

Stone tile that does not have excessive lippage. Photo from Premier Tile of Oaksmall, Calif.

The challenge in trying to meet the standards to minimize tile lippage has to do with a number of compounding conditions. One of those conditions is the condition of the substrate in terms of flatness, which can affect tile lippage particularly when you are adhering direct to a concrete slab. Per industry standard ANSI A108.02-2013-4.1.4.3.1-.2, the substrate needs to be prepared prior to the tile installation so that the maximum allowable variation from the required plane for tiles with all edges shorter than 15 inches (380 mm), is no more than 1/4” in 10 feet (6 mm in 3 m) and no more than 1/16” in 1 foot (1.6 mm in 0.3 m). For tiles with at least one edge 15 inches (380 mm) or longer, the maximum allowable variation from the required plane is not more than 1/8” in 10 feet (3 mm in 3 m) and no more than 1/16” in 2 feet (1.6 mm in 0.6 m). A very irregular substrate makes it difficult for the tile installer to compensate and install the tile so lippage is minimized.

Medium bed thin-set mortars:not designed to compensate for out-of-tolerance substrates

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Limestone with excessive lippage.

Many tile installers and specifiers misunderstand the use of medium bed thin-set mortars. There is a misperception that medium bed thin-set mortar adhesives – which can be applied as thick as 3/4” with some products – will compensate for substrates that are excessively out of plane. Industry standards for thin-set mortar adhesives, such as modified dry-set cement mortars standard ANSI A118.4-2012-2.1, clearly state that thin-set mortars are designed as direct-bond adhesives and are not intended to be used in truing or leveling underlying substrates or the work of others. Substrates need to be prepared before adhering the tile to them. High spots on concrete slabs need to be ground down and low spots need to be filled with special patching

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Limestone installation without excessive lippage.

mortars. Cementitious self-leveling mortars can be used over concrete and wood subfloors to achieve the appropriate flatness or slope to meet project requirements. Medium-bed mortars are only meant to be used for large-and-heavy tiles so they don’t sink into the thin-set mortar during the installation, or to be used to compensate for ungauged tiles that vary significantly in thickness from each other.  Because of this common misunderstanding, the industry is in the process of eliminating the name “medium-bed mortar,” and changing it to “dry-set mortar for large- and-heavy tile (LHT mortar), which is limited to 1/2” (12 mm) thickness after embedment.

Tile warpage

Another compounding factor that can contribute to excessive tile lippage is how much warpage the tile has. Today with such large tiles, particularly the rectangle shapes whose long-to-short-side ratios can be extreme, tile warpage can cause unavoidable actual or perceived lippage, which is discussed later.

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Measuring 1.8 mm (9/128”) of tile lippage, which is excessive for stone, but acceptable for ceramic tile.

Please note that all ceramic tiles, including porcelain tiles — which are a type of ceramic tile — have some degree of warpage. This isn’t anything new. The irregularities in ceramic tile, just as in natural stone, are what give these products their character and desirable appearance. Ceramic tiles have always had warpage and other dimensional variations, although today’s current manufacturing technology results in greater consistency in ceramic tile production. The ANSI A137.1 Specifications for Ceramic Tile standard has established allowable tolerances criteria for each type or category of ceramic tile.

Calibrated versus rectified tiles

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Measuring excessive tile lippage in stone at 4 mm (5/32”) on a floor tile.

Porcelain ceramic tiles are much denser and are more controllable in their manufacturing, although they do have warpage. Standard calibrated porcelain tiles have tolerance requirements that allow more variation in warpage and sizing dimensions. Rectified porcelain ceramic tiles have been ground after manufacturing so their dimensional tolerance variations are much more limited. This allows the tile to be installed with a narrower grout joint width. Some manufacturers will say the grout joint can be as narrow as 1/16” (2 mm), although I never recommend a grout joint less than 1/8” (4 mm) wide. A 1/16” (2 mm) wide grout joint is too narrow to adequately fill to full depth for maximum support of the tile edge. Failure to fully fill the joint can result in grout coming loose later.

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Natural stone slate floor installation that shows excessive tile lippage due to improper installation

The 1/16” (2 mm) wide grout joint also isn’t wide enough to allow for adjustments during the installation to help compensate for dimensional tile variations and to help minimize the potential for tile lippage. The more dimension variation a tile has, the wider the grout joint should be to keep grout joints looking consistently straight and to minimize potential tile lippage. That is why you see grout joints on irregularly-sized Mexican paver tiles that are 3/4” (20 mm) wide or wider, which helps compensate for the broad variations in their dimensional sizes.

Grout joint widths

ANSI standards and the MIA state that the grout joints can never be less than 1/16” (2 mm) wide. I often see where tiles are butted together and this can lead to some serious problems. One potential problem is tile edge chatter where the edges of the tile chip because the tiles compress against each other. This is caused by normal expansion within the tiles caused by moisture or temperature fluctuations or from the dynamic building structural movements.  Another potential problem with tiles butted up to each other, particularly if there aren’t adequate movement joints installed within the tile assembly, is that tiles can become debonded and tent up from the compression stresses; particularly if they are not bonded well to their substrate.

Measuring tile lippage of 2 mm (5/64”).

Measuring tile lippage of 2 mm (5/64”).

Staggered tile pattern standards

Tile warpage generally occurs at the tile corners or at the center of the tile. For that reason the ANSI A108.02 standards state for running bond tile patterns (tiles are installed in a staggered or offset pattern) using tiles where any tile side is greater than 15” (380 mm), the grout joint size shall be on average a minimum of 1/8” (4 mm) wide for rectified tiles, and a minimum of 3/16” (5 mm) wide for calibrated tiles. The grout joint width shall be increased over the minimum requirement by the amount of edge warpage on the longest edge of the tiles being installed. For example, for a rectified tile exhibiting 1/32” (1 mm) edge warpage on the longest edge of the tile, the minimum grout joint width will be 1/8” (4 mm) +1/32” (1 mm) or 5/32” (5 mm) for running bond tile patterns. Again, the wider the grout joint the more you can minimize irregularities in the tile and minimize tile lippage.

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Measuring excessive stone tile lippage of 2.38 mm (3/32”).

Warpage concentration limitations

Currently the ANSI A137.1 standards don’t limit how much warpage can be concentrated within certain spans of the tile. This can be problematic because the tile might not exceed the maximum allowable warpage, but its warpage could be concentrated at the tile corner or at the center of the tile, for which the tile installer can’t fully compensate. For this reason the ANSI committee is currently considering adding language to the standards to limit warpage concentration.

Staggered tile pattern limitations

Because tile warpage can be so much more problematic with tiles that are being installed in a running bond pattern, there are other limitations stated in ANSI A108.02-2013-4.2.3.8.2. This particular standard covers the compounding effects of the warpage from two adjacent tiles. It states that tiles being installed in a running bond pattern where the tile side being offset is greater than 18” (457 mm) long, the running bond offset cannot exceed 33% of the tile length, unless otherwise specified by the tile manufacturer. Mock-ups should always be required for approval prior to the tile installation to make sure that the end user understands what they are getting and to avoid any false expectations.

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Note gap between two tiles at end and the concentrated warpage at the end of ceramic tile wall.

How to calculate allowable tile lippage

Now let’s go back to the allowable tile lippage standard that says that the allowable lippage is either 1/32” (1 mm) or 1/16” (2 mm), depending on the tile and the width of the grout joint, in addition to the inherent warpage of the tile manufactured in accordance with ANSI A137.1. Tile Council of North American (TCNA) website (www.tcnatile.com) interprets this as meaning that the inherent warpage of a particular tile is the actual warpage that the specific tile has when installed. Some people incorrectly interpret this to mean that you can take the maximum allowable warpage stated in ANSI A137.1 and add that to the respective allowable lippage value. If that were true, then in my opinion, from a standard-of-care point of view for professional tile installations, the calculated lippage would be unreasonable and excessive.

Square edge versus chamfered edge tile

Another compounding factor that can contribute to excessive tile lippage is whether the tile being installed has a sharp square-edge or if it has an arris with a slight chamfered edge. The sharp square-edge tiles are more prone to showing tile lippage and other variations, where the chamfered edge tile will be more forgiving. The chamfered edge will make the grout joint width wider at the tile surface.

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. Donato 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. Donato can be reached at [email protected]

Tech Talk – January 2016

TEC-sponsorSelecting the right grout for the job

By Tom Domenici, TEC Western Technical Manager, H.B. Fuller Construction Products

It’s easy for contractors to get lost in the sea of grout product offerings. While grout color is crucial to design, grout type is integral to tile installation performance and longevity. Using the proper grout for a job helps ensure a successful tile installation – it’s only a matter of learning what grouts work best for specific applications.

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Whether it’s cement, ready-to-use, or epoxy grout, taking the time to properly select a grout suitable for a specific job is critical to a successful installation.

Cement grouts: sanded or unsanded? 

Cement grout, which is made of cementitious powder, is easy to work with and is traditionally valued by contractors. Cement grout is mixed with water, and is then slaked and remixed before application. This allows the water, portland cement and other ingredients to react properly for a successful installation. Cement grout can be either sanded or unsanded.

Unsanded cement grout is designed specifically for grouting small joints up to 1/8” wide. Unsanded grout is often used on walls, tub enclosures and countertops. It also can be used for grouting marble and other natural stone floor, where sanded grouts could scratch delicate tile surfaces. Unsanded cement grout should not be used on grout joints greater than 1/8” in width as it may shrink or crack.

Sanded cement grout can be used for grout joints 1/8” wide and larger. Sanded grout is primarily used for floor tile applications or for walls and countertops with wider joints. Sanded grout should not be used on certain tile surfaces, including sensitive glazed ceramic tile, glass, marble, stone and agglomerate tile as it can scratch, stain or damage the tile surface. Follow tile manufacturer recommendations or test a small area prior to use to determine its suitability.

Ready-to-use grouts 

Ready-to- use grouts can provide a crack/shrink/stain-resistant grout solution for time-sensitive installations. Premixed grouts are often used in both interior and exterior environments. Unlike cement grout, ready-to-use grout doesn’t require mixing with water. The pail can be simply opened and the grout applied – saving mixing time. In addition to time-saving benefits, another advantage of ready-to-use grout is that unused portion of the product can be sealed in the container and can be reused later for touchups or other jobs.

Epoxy grouts

Made of epoxy resins, epoxy grout is extremely durable and virtually stain proof. It is ideal for environments that are exposed to harsh conditions or chemicals – such as commercial kitchens and restaurants. However, epoxy grout may be difficult to work with during installation.
Whether it’s cement, ready-to-use, or epoxy grout, taking the time to properly select a grout suitable for a specific job is critical to a successful installation.

The TEC® brand is offered by H.B. Fuller Construction Products Inc. – a leading provider of technologically advanced construction materials and solutions to the commercial, industrial and residential construction industry. Headquartered in Aurora, Illinois, the company’s recognized and trusted brands – TEC®, CHAPCO®, Grout Boost®, ProSpec®, Foster®, and others – are available through an extensive network of distributors and dealers, as well as home improvement retailers. For more information, visit www.hbfuller-cp.com.

Tech Talk – September 2015

TEC-sponsor

NTCA Reference Manual:
General statements on mold, moisture emissions

Pools, showers, wet areas and tubs, by their very nature, are at high risk for both mold and moisture emissions. The NTCA Reference Manual addresses these issues in Chapter 7 with General Statements on both Mold and Moisture Emissions. If you are working in bathrooms, pools, steam showers or wet areas, familiarize yourself with these recommendations. For more helpful information, obtain a copy of the NTCA Reference Manual. Not a member? Visit the NTCA Store at www.tile-assn.com and purchase one today.

General Statement on Mold
MOLD OVERVIEW – CONCLUDED FROM RESEARCH

Mold is one of the biggest enemies in our homes today. Molds are simple microscopic organisms called “Fungi” that are found in the environment. The majority of molds live in plant or animal matter and are necessary for life on earth. Mold is, in fact, the method by which nature cleans up unwanted matter on earth. Mold has existed since the earth was formed. It is only now, due to our improved tighter construction methods, that moisture is being trapped in our homes, causing mold growth problems. It is not necessary to spend time or money to identify the specific type of mold present; most customers consider all molds bad.

There are 3 basic categories of mold that are of interest to the ceramic tile industry:

1. Superficial, which is a maintenance issue.

2. Chronic existing mold, which requires professional mold remediation help, and

3. Potential mold, which is the main area of our concern. Preventing moisture intrusion will prohibit mold growth in the area of the tile installation. Mold requires 4 elements to grow: Mold Spores, temperature, food source, and moisture. The only requirement in the tile installation that can be controlled is moisture availability. Moisture control is, in fact, mold control.

tt-mold1WHAT TO DO WHEN MOLD IS DISCOVERED ON JOB

When you discover existing mold in an installation you must:

1. STOP. DO NOT proceed. Stop all work immediately.

2. Notify all appropriate contractors/owners involved with the job. A mold remediation expert should be hired. The liability of mold or its remediation is not the responsibility of the tile installer.

3. Do not proceed with the job until ALL parties have signed off that the mold situation is addressed properly and that all concerns were satisfied.

4. To prevent mold from reoccurring, all tile assemblies should be installed carefully and correctly, including but not limited to using mold resistant materials. Moisture control products can be utilized to prevent any moisture from penetrating the tile work and possibly re-activating the mold.

tt-mold2General Statement on Moisture Emissions

PURPOSE: The intention of this general statement is to bring to the attention of the tile contractor the problems of moisture emission in certain installations.

Many conventional tile installations have few problems with moisture emission. Ceramic tile typically does not have the same type of problems as wood, carpet, and vinyl when it comes to moisture emissions in as much as the moisture typically does not affect tile installations; however, some other flooring materials either do not allow moisture to pass through them or may be sensitive to moisture and therefore may be adversely affected by moisture. A tile contractor should be careful when installing the following materials over concrete slabs:

• Agglomerate tiles – (cement or resin based)

• Stone tiles

• Setting with epoxy

• Grouting with epoxy

• Non-vitreous tiles with epoxy grout

• Terrazzo tiles

• Efflorescence (cement grouts)

• Organic adhesives

• Concrete tiles

• Crack isolation or waterproof membranes

In these installations, the membrane, setting material and tile or stone manufacturer should be contacted for further instructions and for moisture emission protection requirement.

The tile contractor should bring any issues of the substrate to the general contractor’s attention (or owner, if there is no general contractor). The general contractor, builder, or owner should pay for random Calcium Chloride tests (ASTM F1869-04). The tile contractor/general contractor or tile contractor/owner should agree on who will perform the tests, and what kind of moisture test should be done.

Tech Talk – August 2015 “Green Issue”

TEC-sponsor

Encountering steel trowel-finished concrete floors that do not have a fine broom finish

lynchBy Tom D. Lynch, CSI

Every thin-set, applied-tile installation method over concrete substrates found in the TCNA Handbook for Ceramic, Glass and Stone Tile Installation calls for floors to “have a steel trowel and fine broom finish free of curing compounds.” When encountering floors that do not meet this criteria, a myriad of unanswered questions immediately arises:

What process should be used to scarify the floor to make it comparable to a fine broom finish, e.g. acid etching, grinding, or shot blasting? Is there an industry-acceptable alternative to a fine broom finish? If so, what is it? There is also the issue of possible residue left from curing compounds, which the concrete contractor may or may not admit to using. Lastly, who is to pay for prepping the surface to comply with the architect’s specifications and the TCNA Handbook?

(Ed. note: NTCA, in conjunction with ASCC, NWFA and FCICA issued a joint position statement: Division 3 versus Division 9 Floor Flatness Tolerances, Position Statement #6. This statement addresses some of the questions raised in this story. It is contained in the 2015/2106 NTCA Reference Manual, which can be ordered at www.tile-assn.com)

Good questions all, but why do floors scheduled to receive ceramic tile hardly ever have a fine broom finish in the first place? There are many possible answers to this question. The fine broom finish requirement appears in the 09300 tile specifications, but one must usually refer to the selected TCNA method of installation to see it spelled out in writing. Concrete contractors most likely do not read the tile specs when bidding a job and they rarely own a TCNA Handbook. Many times room finish schedules calling for vinyl composition tile or carpet that do not need fine broom finishes may get upgraded to ceramic tile long after the concrete has been poured. Another scenario might be that slabs get poured in large open spaces long before interior walls get erected, so mapping out areas that are to receive tile becomes difficult and time consuming for the concrete contractor. No matter what the reasons, a fine broom finish must be applied to freshly-poured concrete and that means it is/was the responsibility of the concrete finisher to apply; not the tile contractor.

CSP-kitLet’s get back to the issue of what can be done to make a smooth steel-troweled finished slab acceptable to receive tile. I have a suggestion. The International Concrete Repair Institute (ICRI) has developed a Concrete Surface Profile (CSP) system to shed some light on concrete surface preparations. The CSP “kit” contains a set of nine samples of different degrees of scarification that can be obtained by shot blasting concrete floors.

shotblastingmachineShot blasting machines can utilize different-sized steel shot that get blasted onto concrete floors under varying degrees of force for different lengths of time to develop a desired profile.

Slab texture is of paramount importance to enhance good bond performance for thin-set mortars and my experience has shown that a CSP-3 profile closely resembles the texture that a fine broom finish on freshly poured concrete will provide. As an added benefit, shot blasting can remove curing compound residues that might be present on the surface of the concrete.

Concrete Surface Profiles are currently being used to prepare concrete floors for many types of floor finishes such as trowel applied epoxy resins. These CSP profile ratings are something that can be architecturally specified, so maybe it is time to get our industry involved and officially include them in thinset-applied ceramic tile installations. It would definitely reduce installation failures, and that is really what this article is all about!

 

Tom D. Lynch is an experienced and accomplished technical consultant to the ceramic and stone tile industry. Honored to be one of the first Recognized Industry Consultants by the NTCA, Lynch now has 53 years of experience from which to draw. He can be reached at 181 Sunnyside Park Road, Jefferson, NC 28640 or by phone at 336-877-6951. Website is www.tomlynchconsultant.com. Email at [email protected]

Tech Talk – July 2015

TEC-sponsorBuilding the perfect shower

By Lesley Goddin

Installing showers are one of the most frequent jobs encountered by a tile setter – and one of the most challenging. Managing water issues imparts another dimension to the USUAL demands of tile installation projects. In this edition of Tech Talk, we connect with some tile contractors who are experts at shower installations to learn about pitfalls of these projects and how to overcome them with beautiful results.

Top challenges

John Cox, owner of NTCA Five Star Contractor company Cox Tile in San Antonio, Texas, noted that logistics – especially getting materials to higher floors – take some planning. “Most residences do not have elevators, so scaffolding and ladders are the only means of getting materials to the bathroom.”

1-tt-0715Weather also is a contender for “muddying up” bathroom installs. That’s because to achieve the stunning bathroom effects it produces, Cox Tile muds its walls using the one-coat method, which is made all the more difficult when weather conditions are wet and humidity is high.

Both Cox and Buck Collins of Five Star Contractor Collins Tile and Stone in Ashburn, Va., cite walls that are neither plumb nor square as being problems on the job. Collins says this challenge is exacerbated by today’s use of “large-format tiles, seats and recessed niches,” and attacks the problem by plumbing the walls before rebuilding them. Cox added that his company is “exerting more labor and energy correcting workmanship issues,” such as lack of skilled labor and costs to create a plumb and square canvas on which to install tile. “We have to use a scratch and brown coat to our walls due to the depth when they are out of plumb or out of square,” Cox said.

When working with walls that need flattening, Joe Kerber, owner of Five Star Contractor Kerber Tile, Marble & Stone, Inc. from Shakopee, Minn., said that 1/16” sheetrock furring strips, available at big box home centers, can be used to fur out walls that are not flat or straight. He insisted, “Make sure that the walls you are going to set tile on are flat, not necessarily plumb.”

Kerber also noted that pitch to the drain can be a challenge when working with barrier-free showers. (see Kerber’s By the Book article on curbless showers in this issue.) “Sometimes we have to reframe the floor system to accommodate the correct pitch for the particular room,” he said.

Another issue that comes with shower installs is seats that are prone to leaking, Collins said. To alleviate this problem, Collins uses “pre-formed seats and niches to elevate any potential issues.”

Martin Brookes, owner of Five Star Contractor Heritage Marble & Tile, Inc., in Mill Valley, Calif., shared that his company has discovered that sometimes showers “will be redesigned after bid stage to a steam room without the owners being aware of the significant up charge and design changes to accommodate this scenario.”

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Top tips for shower installs

Much of the wisdom around shower installs centers on waterproofing – clearly a key component to any successful shower or steam room project.

Cox recommended that contractors, “Understand and know the value in waterproofing. Especially niches, benches, seats, jambs and window frames. These are long-term problematic areas that do not get treated properly. They show up later down the line and are generally costly problems to correct.” Brookes declared that “Waterproofing the shower enclosure and shower pan is key in longevity of the shower stall. It’s critical to identify ahead of time if you need a trench drain instead of a traditional shower drain. Not every application will allow for the use of a trench drain with a barrier-free walk-in type shower stall. Sometimes the floor will need to be re-engineered to accommodate this application. Steam room applications will require a whole different approach and a different set of specifications to make it fully functional.” And be sure you “have proper pitch to the drain on all horizontal surfaces,” Kerber said.

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Brookes confirmed, “The importance of waterproofing all niches and penetrations should be understood. All mounted accessories should be considered, and appropriate backing installed before preparation work begins. Follow the rules and understand the waterproofing requirements and your installation will survive for many years to come.” Brookes underscored the importance of reading and clearly understanding TCNA standards, as well.

Kerber pointed out, “Use correct installation procedures for your waterproofing. Remember, it’s not just waterproofing, its water management.” He also emphasized that contractors “get a good layout of the tile selections on all the walls, whether it is only two or as many as nine – as is the case of a shower we are working on right now. Sometimes this process takes time, practice, patience, and wisdom.” Kerber stressed using mortar or thinset to install tile. “Absolutely no acrylic adhesives in a shower,” he said. And use “premium grouts and caulks. No acrylic caulk at the shower floor.”

4-tt-0715Another essential is proper installation of shower pans, Cox said. “Understand that a shower is a working assembly,” he explained. “Pre-slope is critical, folding your corners, wrapping your curbs, and putting the proper corners on where needed. We build ours with bricks or blocks for long term. Also know that any curb built with wood cannot have any fasteners on the top or inside that will lead to water intrusion.”

And above all, before even starting, “Educate the builder and framer on how it affects your labor when they do not pay attention to their quality control,” Cox concluded.

Tech Talk – June 2015

TEC-sponsor

Hot Weather Tiling

2014/2015 NTCA Reference Manual

Since summer begins this month, we are literally taking a page (or two) from the 2014/2015 NTCA Reference Manual that relates to hot weather tiling. Materials require special handling to reduce the individual or combined effects of high temperature, low relative humidity, and high winds.

For instance, portland cement mortars and grouts can require additional water or latex for mixing, which can affect the bond and result in less open time, higher incidence of skinning over, plus dry-shrinkage cracking and improper curing.

In hot weather, organic adhesives produce creamier textures and increased workability that may lead to troweling too large an area before applying tile, as well as faster skinning over. Hot weather can sometimes reduce the viscosities of epoxies, making them more workable and at the same time accelerating the rate of cure, which can wreak havoc with mixing equipment and leave an epoxy film on the tile that’s very difficult to remove.

What follows are recommendations from pages 140-141 in the 2014/2015 NTCA Reference Manual that support well-performing installations by minimizing or controlling conditions that result from hot weather for projects that must be executed in hot weather conditions due to budgetary and scheduling demands.

Be sure to consider each project individually, since following one recommendation may not be sufficient to rule out problems. Evaluate exterior installation sites in advance, observing how many hours a day the installation will be exposed to direct sunlight and winds, and whether it’s feasible to construct a temporary shelter that can be moved as work progresses or if the work is better done at night or a cooler time of day.

In addition to temperature of materials, you must monitor temperatures of the job substrate. Hot substrates will exacerbate the hot weather effects of skinning over, reduced workability, premature drying and inability to form a strong bond for cementitious grouts and mortars. If you choose to cool a substrate with water, be sure to remove all excess water before applying the mortar.

Materials

Keep all materials in a shaded area and do not store materials in closed trucks or vans. This includes tiles, mixing liquid, setting and grout materials. If any material is warm to the touch it is suspect.

Don’t use tile that is hot to the touch. Cool your materials before proceeding. Some manufacturers market products specifically developed for hot weather conditions. They can be consulted concerning their products’ performance and recommendations under specific job conditions.

 

Portland cement

mortars and grouts

If using water, fill buckets and put them in a shaded area. If possible, use a combination of ice and water. Mixing water has the greatest effect per unit weight of any of the ingredients on the temperature of a cementitious mortar or grout. It has a specific heat* between four or five times that of cement or aggregate. Thus a change in water temperature of about 4 degrees Fahrenheit can effect a 1 degree Fahrenheit change on a mortar or grout. By using ice water, a more dramatic temperature change can be effected. The use of cold water will result in a decreased water demand of the mortar or grout when mixing. The working time of the mortar or grout will be increased and the workability will be improved. Using warm or hot water will cause an increase in water demand, consequent decrease in performance, a rapid loss of workability and decreased pot life. An analogous situation exists for latex additives. Except here, the addition of ice to the latex admixture is not recommended. A better recommendation would be placing the latex admixture containers into an ice chest filled with crushed ice. The containers can then be removed and the pre-cooled latex used as needed. Before applying dry-set or latex modified portland cement mortars to concrete substrates, dampen the concrete to cool it down slightly. Control how much mortar is troweled and combed before setting the tile. High temperatures and wind can combine or skin a mortar in several minutes. Check for mortar transfer to the tile backs often as the installation proceeds. Scrape off and discard skinned mortar and apply fresh material whenever skinning is noted. Never re-temper or add additional liquid to a mortar or grout that has lost its workability. Begin damp curing installations involving unmodified cementitious materials as soon as it is practical.

Rapid water loss can result in dry-shrinkage cracking that will compromise the integrity of the installation and ruin an otherwise acceptable grout application.

 

Organic adhesives

The viscosity of organic adhesives decreases with higher temperatures, making it easier to spread and trowel. Avoid the tendency to spread too large an area before tiling. In higher temperatures and in the presence of drafts, organic adhesives skin over rapidly, preventing good transfer of adhesive to the tile being installed. Check transfer often by removing a tile and observing the amount of adhesive on the tile back. Cooling the adhesive will help somewhat, but cooling in an ice bath is not recommended since the workability of the adhesive will be adversely effected by the increased viscosity.

 

Epoxy mortars and grouts

Every effort possible should be made to keep the temperature of the epoxy, tile and substrate below 90 degrees Fahrenheit. This may require working at night, the use of ice baths to cool the mixed epoxy and control its rate of setting or the application of damp blankets or towels to the installed tile before grouting in an effort to cool them. Do not overmix the epoxy mortars or grouts. Do not pre-moisten concrete substrates before applying epoxies. All manufacturers of those materials require that the components be intimately mixed for optimum performance. This can be observed as a homogeneous lump-free mix or by a thorough wetting of the aggregate or by uniform color. When any of these conditions is observed, STOP MIXING! Excessive mixing will accelerate the rate of cure still further from the heat generated by the mixing action.

When grouting, do not attempt to grout large areas of the tile field before cleanup. The result can be an extremely difficult-to-remove cured epoxy film on the tiles.

 

*Specific Heat – The ratio of the heat capacity of a substance to the heat capacity of water, or the quantity of heat required for a I degree temperature change in a unit weight of a material. Commonly expressed in Btu/lb/degree F or in Cal/g/degree F.

Coming this summer – the second annual issue of TileLetter TECH! Learn about hot topics in the current NTCA 2014/2015 Reference Manual and changes coming to the 2015/2016 edition.

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