Protecting Tile and Stone with Six-Sided Sealing...entering the tile and creating “picture framing” around the perimeter. Because the tiles are pre-sealed, they are protected from

By Steve Taylor Director of Architecture and Technical Marketing, Custom Building Products

Technical White PaperSIX-SIDED SEALING

Protecting Tile and Stone with Six-Sided SealingPrevent Moisture Migration Prior to Installation Many porous tiles are sensitive to moisture, including natural stone such as marble or limestone, cement agglomerate (terrazzo) and synthetic agglomerate (resin terrazzo) tiles. Even the water in the mortar used to install such porous tile can stain or warp it after installation. Moisture entering the tile can enlarge minerals and resins in the tile body, causing the tile to warp and curl. This water can also transport salts through the tile that appear on the surface as a stain or efflorescence.

Preventing water from being absorbed into the tiles during curing of the mortar and grout is critical, but other sources of moisture can have an equally damaging effect. Moisture in a concrete slab can migrate through capillary action into the tile assembly and cause damage. Environmental exposure to weather conditions, interior wet areas, accidental spills and joint fillers are other causes of irreversible staining.

Sealing all sides of the tile prevents water from entering the tile and moving to the surface. When the tile is sealed on all six surfaces with an appropriate sealer, damage from moisture exposure and capillary migration will be minimized.

Penetrating and Impregnating SealersCUSTOM has a full line of sealing products to prevent moisture damage to natural stone or agglomerate tile. We recommend six-sided sealing of the tile with one of our Aqua Mix® brand penetrating sealers:

• AquaMix® Ultra-Solv® is a premium quality sealer that achieves maximum stain protection, offers expected wear up to 15 years and is solvent-based for fast drying.

• AquaMix® Penetrating Sealer is an economical choice with excellent stain protection, 5 years of expected wear and a low VOC, water-based formula.

Both of these products retain the natural look of the tile or stone, with no sheen after application, and allow the transmission of moisture vapor to maintain the breathability of the stone.

Some tile and stone will benefit from an enhancing sealer that will darken and highlight its character. Conduct a test with one of the penetrating sealers above and compare the results with those from an enhancing product like Aqua Mix® Enrich ‘N’ Seal®. Remember that an enhancing sealer cannot be applied over a penetrating sealer, so choose a natural or darkened look before beginning the six-sided sealing process.

Six-Sided Application of SealerThere 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 tile in the penetrating sealer and allow the sealer to be absorbed into the tile. The tile should be submerged for several seconds – long enough to achieve maximum penetration to the front, back and all four sides. After being removed from the sealer bath, the tile must be must be wiped free of any excess sealer on the surface.

Regardless of the sealing method used, it is important to wear chemical-resistant gloves during the application of sealer.

Sealing all sides of the tile prevents water from entering the tile and moving to the surface.


The sealed tiles should be set up on narrow supports so that air can get to all sides, and allowed to dry thoroughly. It is important that the sealer is completely dry before installing with cement-based mortars. After sealing, test tile samples to ensure that water beads on all six sides. If water does not bead on the surface, the tile needs a second treatment of sealer.

Choosing the Right MortarAqua Mix Ultra-Solv and Penetrating Sealer cure just below the surface of the tile. Because of this, the surface remains available for a bond to an appropriate dry-set mortar. The sealed tile is much like a very dense stone or porcelain tile and requires mortars with high polymer content to assure adequate bond strength for years of use. CUSTOM’s MegaLite® and ProLite® mortars are advanced, premium formulas with the polymer content to achieve a superior bond to the back surface of the sealed tile. Both mortars are also ideally suited for floor or wall installation of heavy stone or large format tile with one or more sides longer than 15".

Note: Since all stones react differently to sealers and the moisture in the bonding mortar, it is important to build a mockup with the tiles and mortar to be used on the job. Proceed only if the end user or design professional is satisfied with the results of the mockup. If there are any questions, contact CUSTOM Technical Services at 800-282-8786 before beginning your project.

Additional Benefits of SealingWhen the face of the tile has been pre-sealed, grouting becomes a faster and easier process. The sealer will prevent the grout from potentially staining the face of an otherwise porous tile. Sealing also makes it easier to remove grout from the face of the tile during cleaning, similar to using a grout release product. Since all sides of the tile have been sealed, water will not migrate into the stone and darken it. Six-sided sealing will prevent dyes in grout and silicone sealant from entering the tile and creating “picture framing” around the perimeter.

Because the tiles are pre-sealed, they are protected from accidental spills during the first few days after installation. Normally the installer or owner must wait three to five days for the grout to cure before sealing the entire installation. During this period, the tiles are typically unprotected, but pre-sealing eliminates this concern.

The next time you are asked to install a porous or moisture-sensitive tile, consider six-sided sealing before the installation. The extra time involved pre-sealing can protect against costly damage and additional work to a tile installation by preventing damage from moisture migration and staining.

When the face of the tile has been pre-sealed, grouting becomes a faster and easier process.


Custom Building Products Technical Services 800-282-8786

Architectural Services 800-272-8786custombuildingproducts.com

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©2015 Custom Building Products. All rights reserved. The CUSTOM ® logo and select product logos are registered trademarks of Custom Building Products, Inc. CUSTOM may make product modifications at any time without notice. Visit custombuildingproducts.com for updated technical data sheets and SDS information.

About the AuthorSteve Taylor is Director of Architecture and Technical Marketing for Custom Building Products and has more than 30 years of experience developing products for the construction industry.

Steve is a member of the Tile Council of North America (TCNA) and Materials & Methods Standards Association (MMSA). In these roles, he helps to determine proper tile installation methods and standards. This includes simplifying the tile installation process to save tile professionals time and money.


Note: Over time, protection from the sealer will be affected by the hardness and texture of the material, surface wear, weather conditions and cleaning regimens. All sealed tile and stone should be periodically tested, at least annually, to ensure that water is still beading on the surface. If any water penetrates, it indicates that an additional coat of sealer should be applied to continue the moisture and stain protection of the tile.

Protecting Tile and Stone with Six-Sided Sealing...entering the tile and creating “picture framing” around the perimeter. Because the tiles are pre-sealed, they are protected from

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