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Six-Sided Sealing (cont.)

A NEW APPROACH: SIX-SIDED SEALING Due to the potential problems of moisture, some believe there is no alternative but to not use, sell or specify certain stones that may pose a challenge. The good news is, there is another ap proach that can be implemented to aid in the management of wa ter, thus allowing natural stones to be successfully installed. By sealing all six sides of the stone or tile, water is prevented from entering and moving through the material to the surface, thereby potentially triggering one or more of the potential moisture issues outlined. With the right sealer, potential damage from moisture exposure and capillary migration will be reduced and possibly eliminated. Six-sided sealing is an important component (not the sole solution) in creating a successful water management system for these installations. Managing the amount of water that can be absorbed by the stone or tile during and after installation is the best way to re duce the risk of moisture problems from occurring. However for a sealer to work successfully in this environment, the sealer must have two important characteristics. The first is the sealer does not interfere with the bond of the adhesive. The second is the sealer can perform in the high-alkaline environment of the curing cement adhesive or mortar. For many years in the indus try, sealers have been seen as either bond breakers or prod ucts that significantly reduce the effectiveness of an adhesive. Therefore sealers have not been recommended or advocated for the use of sealing the back and sides of stone and tile. The tile and stone industry has acknowledged the potential ability of sealers to reduce the risk of staining during installation. While not commonly used in North America, six-sided sealing has been recognized and used successfully around the world from Europe to Asia to the Middle East for decades. Six-sided sealing has been experienced by many companies and indus try professionals around the world. Manufacturers that use the highest quality raw materials and latest chemistry advance ments have produced sealers that are not bond breakers and can perform effectively in a high-alkaline environment, making the sealer suitable for application to all six sides of a stone or tile. As most sealers are not suitable for the six-sided sealing process, the chemistry of the sealer is critical to ensure suc cessful results. The right chemistry not only allows for proper performance in a high-alkaline, wet environment, but due to the sealer residing within the stone or tile and not on the surface per se, six-sided sealing ensures the ability not to interfere with the bond of an adhesive, cement mortar or grout. Two questions often asked are: Does the six-sided sealer still allow for the ad hesive to cure and stone to breathe? The answer is yes for both. With regard to application, first any dust or residue should be brushed off all sides of the stone or tile material. Since fabri cating stone tiles or pavers is a wet process, elevated mois ture readings may occur when natural stones are immediate ly removed from the crates, boxes or packing containers. For best results, allow the moisture to dry out prior to sealing. Use a moisture meter prior to sealing to verify the present moisture

content, and discuss with the sealer manufacturer and other parties to the project to determine the best course of action if elevated moisture levels are detected. There are several ways to apply the sealer to all six sides, such as brushes or paint rollers, but the most effective and efficient method is to submerge the stone or tile in the sealer and allow for full absorption into the stone or tile. The stone or tile should be submerged on average for 10 to 15 seconds to achieve max imum penetration, but the time may vary by stone. After being removed from the sealer bath, the tile or stone must be must be wiped dry of any excess sealer on the surface. In some cases a squeegee can be used to remove any excess sealer. Again, test ing is always recommended as the type and texture of the stone or tile, jobsite conditions, and variables along with the experi ence of the person(s) applying the sealer will vary. The sealed tiles should be set up on narrow supports so that air can get to all sides, and allowed to dry thoroughly. (Photo 6) The sealer must completely dry on the tile or stone before installing with cement-based mortars. After sealing, test tile or stone sam ples to ensure that water beads on all six sides. The cure time and process will vary based on product used and conditions outlined above.

Photo 6: Ensuring tiles are staged for proper sealing and cure.

DOES SIX-SIDED SEALING MANAGE THESE PROBLEMS BY ITSELF?

Since sealers do reduce and slow down water absorption (but ultimately do not stop water totally because the sealers are not waterproofing materials), the sealers are a critical component of a full water management system, but are not the complete answer in-and-of themselves. A full water management system should be considered and the appropriate components imple mented across the entire assembly to fully protect the instal lation from the staining and contamination. Six-sided sealing systems will have other benefits in terms of helping to reduce the risk of other water related problems such as freeze/thaw damage and dimensional deformation (warping), a well-docu mented problem with water-sensitive stone. So what are the main components of a water management sys tem? There are a number of elements to this system that should be considered when designing, specifying, selling or installing. The main components are as follows:

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NTCA Reference Manual | 2024 / 2025

Chapter 6 | Natural Stone Installations