Technical Focus: The Evolution of Grouts and Mortars
Over the last several decades, the types of grout and mortar products available on the market have drastically changed, offering consumers and professionals more choices for specified projects
Generally viewed, grouts and mortars are enormously overlooked compared to their more colorful ceramic tile, stone and glass tile counterparts. With the advancement in tile manufacturing, there has been the introduction of more composition types and larger sizes. These larger format tiles have gained popularity and are more commonly used, yet the grouts and mortars go much less noticed. More mortar selections for tile bonding provide consumers and installers the best fit and more of a selection than past installations.
Grouts types have also changed to give consumers and installers various degrees for performance. There are existing groups of installation products with a “system warranty” to offer levels of protection. The “one-size-fits-all” mentality is no longer a default response. The consumer and installer have much better technology products to select from.
Then and now
While the primary function of all setting mortars and grouts is to bond tile, the performance has been optimized in longevity, durability and workability. These products have been augmented by formulations for the environmental service conditions and increased installation productivity. Installers’ productivity has steadily increased in installed square footage per work day (square feet/man hours) due to the improvement in products. The higher density, tougher tiles or stones — many of physical size, weight and composition — are being changed or increased. Ceramic tiles have dramatically evolved in more advanced composition and dimensional unit sizing.
In today’s marketplace and jobsites, both the labor cost to install tile/stone and the understanding of cost performance with service duty, are major factors of consideration. The professional tile installer approaches product selection much differently when completing a retail mall, school or public airport than with a tile installation for a food/meat processing plant, hospital or restaurant. Clay, porcelain, glass, fiberglass-backed tiles and even composite metal tiles create circumstances for more sophisticated mortar bonding types.
The role of grouts has shifted over the years. In earlier times, from the 1950s to the 1970s, grout was a more economical component, compared with tile cost per square foot, and a very wide joint — from 1/2 inch to 1 inch — was added to the installation. Color choice of grouts were very basic, with white cement wall grouts and gray cement and sand floor grouts. The more elite or extravagant jobsites afforded either black, red, darker gray or buff color selections with the added pigment cost. However, there were challenges getting the color mix consistent and uniform throughout the full installation.
Today, in 2018, grout is a functional, aesthetic “colored” component with a slimmer, more narrow appearance to ceramic tile, stone and glass. There is an array of grout color offerings — between 10 and 40 choices nowadays from each manufacturer. There are resinous grouts to be more stain-resistant and even versions of grout to be translucent. The modern-day grout is a much different product. Although tile joint space or grout width become smaller, there will always be a grout filler component necessary for tilework. Due to non-flawless tile dimensional sizing (tile tolerances ± sizing), the finish continues to be part of a hand-crafted installation process. Some joint or grout lines will remain present in an installation even if the minimum grout space were to be 1/16 inch.
Modifications of sanded and unsanded grouts
Nonsanded or unsanded grouts and sanded grout types from the manufacturers have created hybrid type grouts that are able to function in both narrow and standard tile joint situations. Additional options that have been made available include pre-mixed, resin (waterborne urethane, silicone, acrylic or other) grouts with a self-sealed attribute. The newer, waterborne resin, pre-mixed grouts are not restricted to commercial use, but are now finding applications in residential spaces. Commercial and residential tile applications are still being installed with tried-and-true cementitious polymer/latex grout and mortars. Latex, polymers, urethanes, silicones, acrylics, epoxies and epoxy emulsion enhancements are the industry’s part to produce a cleaner, better stain-resistant grout for the consumer.
Modern day tiles have progressively gotten stronger, harder, thinner, lower in cost and more widely available in the marketplace. The physical strength increases and improved density and weatherability has evolved to where they require a much higher and stronger strength mortar.
A “rock hard” tile bond and grout are not the only kind of product wanted or needed for todays’ modern usage. A more flexible, vibration-resistant mortar/grout is sought after for high-rise condominiums and multi-story buildings or shopping malls. In residential housing or jobsites constructed of EGP, plywood subfloors can be directly bond with industry tile bonding mortar meeting or exceeding ANSI A118.11 or ISO C2S1P1. Tile adhesives company mortars have been created for more substrate-specific situations. Mortar and grout performance minimum levels can be referenced in the TCNA Handbook.
Grout and tile-setting mortars have been matched to glass tile, gauged porcelain tile panels/slabs, large heavy tile (LHT) and all past (clay-bodied) tiles to be cost-engineered (strengthened or reduced) in development for much more effective building cost-management. For example, if mortar flexibility or EGP plywood attributes are not required for an on-grade slab/concrete surface, then a tailored or different mortar can be used for just that type of install (ANSI A118.4 or ISO C2S1).
Why grouts have changed
The development of multiple versions of mortar and grout products is a direct result of customer and jobsite demands, which are mission-tasked or duty-specific. The same 18- x 24-inch tiles on an exterior facade, indoor lobby floor or interior residential wall could be installed with three different duty- and installation-specific mortars. Various mortar types have been developed to address the substrate (gypsum wall surface, concrete subfloor, etc.) or anti-sag (vertical wall) or anti-slump (horizontal floor or countertop) installation placement and weather resistantance. This would include specialized applications or type-specific installation methods to gauged porcelain tile or gauged porcelain panel/slabs, described in the recently released standard, ANSI A137.3. The same would be true for installations with past ANSI standards associated to Glass Tile, ANSI A 137.2, needing the higher bonding mortar to meet or exceed ANSI A118.15 or ISO C2S1, C2S2 in the white version.
The classification of regular tile (less than 15 inches) mortar versions are different from large-format tile (15 inches or larger) bonding mortar. These Large Heavy Tiles (referenced as LHT) or longer plank tiles are not installed in their best manner with “old-style” thinset mortar. The “old-style” or thinset types can and do fail from mortar shrinkage and can lack tile’s physical cracking support, such as point load or impact-stress. The mortar manufacturers promote and sell LHT mortars or formerly referenced medium-bed mortars for these types of installations. Other mortar changes relate to uncoupling membranes and their installation requirements.
Various mortars types can be specified and used to accommodate better and different installations. The exposure, popularity, affordable viability of different tile sizes and composition takes ceramic and stone tile surfaces into expanded use. For the current and future, tile installers or projects will have a wide selection of products that are more appropriate upgrades or best-suited materials with the specific tilework. These will have to be properly attached and installed to the construction-building surfaces to provide a long lasting and attractive finish.
Selecting the right product
How to use and select the better or best products for your project can be daunting at times. Don’t allow your choice to stagnant your options or ability to evolve or get better results. The constant re-use of particular grout and mortar product(s) with five, 10 or 15+ years of usage should make you more open to trying newer installation systems. Company and brand loyalty are great, but to remain impartial with a similar product does not make sense when all the surrounding components (CIM, waterproofing, uncoupling membranes, glass, gauged porcelain, LHT, radiant heat, sound control, etc.) have forever changed the marketplace. Mortars and grouts are part of the installation process like tools of the trade. A simple hammer and nail in construction have become more specialized — ball-peen, air, roofing/shingle, upholstery, framing, brick, etc. — and so have the grouts and mortars. These products now cater to floors, walls, hot weather, cold weather, fast-setting or a repair situation. Newer mortars and grouts have been developed beyond just appearance; they have become an element of service installation and placement. Residential, commercial, industrial, green/environmental, common-use and/or sanitary are the many ways to look at installations.
The best grout selection will be driven by the service conditions. Epoxy, resin grouts are best suited for projects with severe or harsh washing environments or sanitary/hygienic cleaning issues (ANSI A 118.3 or ISO RG). Moderate to heavy cleaning and usage can be addressed by premixed, water-borne resin grout. Light to standard cleaning and usage can be accommodated best with polymer/latex cementitious grouts (ANSI A118.7 or ISO CG 1, CG2), which offer added topical sealers for reduced maintenance (optional).
Older grouts and mortars remain available and ready to accommodate customers; however, newer enhanced versions reduce installation labor due to resistance in stain for jobsite conditions, better color control and reducing long-term owner service care.
The selection of diverse grout types is less about the market and more about product service matching. The more advanced or technologically developed grout will yield the better performance and service duty life for the project.
In CEU lectures and product knowledge sessions, Texrite stresses that all the products will have their “kryptonite condition” or weak match-up conditions. The quickest way to review a product document for proper usage is in the technical data text; you will see “Not recommend for this application” or “limitation include not for…” The manufacturers continue to strengthen and improve product versions with better color retention, stain resistance, low or no efflorescence, and better ease of application. Therefore, grout technology has improved and continues to grow over the years. Grout installation processes will be altered to accommodate the “new” products. It’s much like the car industry, where basic models are cost-effective and available, yet better options with higher performance options can be purchased at a higher price point. Grout and mortar companies have various levels of upgraded, performance, ease-of-application and enhanced features. Maintenance and upkeep are still required. Unfortunately, there no mold-free or maintenance-free grouts to-date. If mold spores, dirt, soaps and moisture are present on the surface of the grout, it can appear as a color changing. Historically, many situations that have a good quality cementitious polymer/latex grout and application of a sealer, combined with proper maintenance, last for many years.
The term “perfect grout” would be more appropriately described as or prefaced as the “best grout for the situation.” For an educated consumer, there are better grout options. Yet, lack of proper maintenance or improper upkeep of the toughest epoxy grout can still have performance challenges under poor conditions, aside from just color change. There is no such grout surface that stops dirt and dust or repels soaps from their surface. The newer products impart less porosity or absorption-blocking technology to reduce maintenance and cleaning, but will not self-mitigate or self-remove surface accumulation. The manufacturers have added antimicrobial additives, densifiers and even integral sealer components to ease the cleaning of the surface.
Education is key
With the advancement of different grout types and changes in grout composition, there will be a need to adapt and acknowledge procedural changes. Newer, pre-mixed grout and epoxy grouts require similar tools, but also require a slight change — the use of a rigid and firm rubber grout float type to change wash-time sequence and grout final clean-up with a towel or micro-fiber cloth. The installers will also have an altered work flow, with shorter time frames needed to grout and clean, opposed to cementitious products that need time to set and clean. Problems have occurred with grout installers who do not recognize the procedural time frame changes for the different grout types. There can be installer/consumer headaches when this altered sequence is overlooked or dismissed when working with the newer technology grouts. The professional tile installer, specifier, architect, designer and sales team will need to undergo continual awareness/educational/training to stay in step with the tile evolutionary changes.
Education and learning is provided through the grout and mortar manufacturers’ installation seminars, contractor workshops and product introduction demonstrations held at local levels with major tile distributors. Additional online help, such as YouTube, is also available for those who are unable to attend seminars or local events. Even a simple request for a jobsite visit or installation training from the manufacturer’s representative are encouraged. Full education resources a can be found directly through manufacturer learning programs/company programs or NTCA regional trade workshops. More in-depth, installation training or certification training can be done through the CTEF and U of CTSE programs.
New versions of products are always being developed to increase productivity and durability. Lightweight and/or easy-to-apply versions of mortars are being created, leading to a reduction in shipping cost, lower stain resistance and added recyclable content. Additional changes and modifications for increased recycled content, low/reduced silica dust, low or no V.O.C. content have created demand changes. There will also be continued development of adhesives for gauged porcelain tile.
Tiles installation have transformed, to say the least. Substrates, membrane systems, tile sizes and composition have improved and changed — and newer grouts and mortars are part of the evolution. The mentality and attitude in which consumers and/or installers see or experience car and auto features upgrades should be compared to tile installation and upgrades in mortars and grouts. There is no longer a “one-size-fits-all” product choice. The newer technology mortars and grouts are able to deliver a better and more desirable fit and finish, from the beginning of the installation to the jobsite owner’s end-use.