Bulletin #12

Revised September 26, 2006

Grout Releases and Sealers for Ceramic Tile

Tiles are either man made or natural. Each has its own appeal and distinct requirements as far as the installation and maintenance concern.

A. Get to know the tiles you are dealing with:

1. Man made:
Ceramic tile is a mixture of clay and talc molded and fired at high temperature resulting in a hard material with relatively high water absorption. Its surface will receive a glazed layer. It is very insusceptible to stains. Porcelain tile is made by the dust-pressed method with a composition to produce a dense and impervious body. Its surface is normally very smooth and unglazed; some has a fine-grained texture. Untreated surface can be susceptible to stains. Concrete tile is made of cements, pozzolans, aggregates and fibers. It is generally cured at high temperature in an autoclave. Its surface is normally untreated. The water absorption is similar to that of concrete. Untreated surface is easily stained. Saltillo or terra cotta tile is molded by pressing quarried clay with a wooden frame and baked. It is notoriously known for high water absorption. The surface is porous and easily scratched and stained if not treated. Tile with sealed surface is also available. The extrusion process makes quarry tile from natural clay or shale. Its surface can be glazed or unglazed with very fine-grained finish. Glass tile is made of glass with smooth surfaces and impervious. Glass tile is not easily stained. Agglomerate marble is fabricated with stone chips blended with resins. It is very dense and has low water absorption. It normally has good abrasion and stain resistance.

2. Natural:
Marble is a metamorphic stone, a re-crystallized rock composed of calcite, dolomite, or serpentine. It is a soft material with a typical 3 Mohs hardness. Its porosity widely varies. It is easily stained and etched by acidic materials such as limejuice.
Other metamorphic stone is slate. Limestone and Travertine are sedimentary stones with wide degrees of porosities. They are easily stained and etched by acidic materials. Other sedimentary stones are Sandstone, Gypsum, and conglomerate.
Granite is an igneous stone, which mainly composes of quartz and feldspar. Granite is normally a very hard and dense material with low porosity. It is susceptible to staining. Other igneous stones are Quartz, Obsidian, and Pumas. Stones are normally available with different surface finishes. Polished finish has a glossy and highly reflective surface, the shine can wear away due to foot traffic. Honed finish has a flat matte with very low sheen. Tumble finish has slightly rough texture of an old world/worn appearance. Other texture finishes are Sand Blasted, Flamed, and Bush Hammered. The type of surface finishes of stone has great impact on its aesthetics but does not reduce the susceptibility to stains.

Neither, man-made nor natural tile is maintenance free. The use of pre-grout release is to protect the tiles from grout stains and the use of tile sealer is to provide the long lasting beauty to the tile. Advancements in chemicals and raw materials have enabled manufacturers to develop a myriad of water- based sealers, topical coatings and pre-grout releases that are easy to apply and require less hazardous chemicals for removal.

B) Pre-grout release.

The pre-grouting release is a protective coating applied to the surface of the tile to facilitate the removal of the grout in the grouting process. It can either be a temporary or permanent coating. The most common type of grout is Cementitious, a pre-blend of cement, sand/limestone, fine inorganic and organic pigments, celluloses, and polymers. The next commonly used grout is a two or more component epoxy for improved chemical and stain resistance. The third type of grout is organic premix, a ready to use. Each requires its own unique technique for grouting and tile care.

1) Grouting with Cementitious grout: glazed tile, porcelain tile with smooth surface, quarry tile, agglomerate tile and glass tile will not require the use of pre-grout release. Porcelain tile with matte finish surface, unsealed Saltillo tile, concrete tile, and all natural stones will require pre-grouting release to protect tiny pores on the tile surface from cement and pigment deposit.

2) Grouting with Epoxy grout: Pre-grout release is highly recommended to facilitate with the clean up.

3) Grouting with Organic Premix: Pre-grout release is highly recommended. The most common pre-grout release is the penetrating type, which is invisible and does not change the appearance of tiles. Penetrating or impregnating sealer can also be used for this purpose. A film forming sealer can also be used. The carrier of pre-grout release can be either solvent or water based. Most manufacturers recommend a minimum cure time for the release from two to four hours prior to the actual grouting.

C) Tile Sealers:

There are many different trade terms for sealers creating confusion. There are three distinct categories for tile sealers:

1) Penetrating or impregnating sealers: Sealer does not alter the appearance and the color of tile, it does not form a film and is invisible. Its chemical and mineral agents absorbed into the pores/capillaries of material on the surface, it modifies the physical properties to resist stains. It allows moisture vapor transmission. It can be a water or solvent base. The most common active ingredients used in this type of products are silicone and fluorocarbons. Silicone based sealer has excellent UV resistance, water repellency, and less resistance to oil based stains. Fluorocarbon based sealer has excellent water repellency; stain resistance, and less resistance to UV. Penetrating sealer can be an excellent pre-grout release. Natural stones are unique and are not alike; they are so different chemically and physically. Sealers are specifically formulated for different types and different finishes of stone to optimize the performance. The sealing mechanisms of stones with different finishes are so different, for example polished and honed marble.

2) Finishing or Topical Sealers: Sealer forms a film on the surface of the tile. It can close pores and reduce the moisture vapor transmission. The coating can be from high gloss to matte finish. It can be a solvent or water base. The most common active ingredients are acrylic, waxes, and polyurethane.

3) Enhancers: It highlights natural colors of unpolished textured and faded stone or masonry. Some enhancer’s seals, other may not. It allows moisture vapor transmission.

C) Grout Sealers:

The most common type of sealer for cementitious grout is penetrating or impregnating. Most manufactures recommendation grout to be cured a minimum of 72 hours before application of sealer. Film forming type sealer can also be used.

D) Tile and Grout Cleaners:

Most popular general-purpose cleaners will etch or damage natural stones or degrade the sealer, therefore removing protective properties and becoming susceptible to stains. Most tile and grout cleaners have neutral pH and free of abrasive materials. It contains chemicals to cut through grease, soap scum; common household stains without damaging grout or tile. Some cleaners have dual purposes as a cleaner and as a re-sealer with anti microbial property. There is also available a heavy-duty Cleaner and Stripper to remove acrylic and wax floor finish or light grout residue. It contains alkali which are ideal for deep cleaning – but should be used occasionally to remove or strip acrylic finishes, waxes, dirt, oil and penetrating sealers.

Understanding the make up of tile, either man made or natural is the key to maintaining it. Currently there is no industry standard regarding these important products. Technology has also advanced enormously in this field to simplify the maintenance of a tile installation. It important to recognize the complexity of natural stones and their wide chemical and physical make-ups, therefore their requirements for maintenance have to be different.