One of the most common questions regarding the sealing of tile and stone is whether it’s actually necessary. The idea of sealing tile assemblies is often ignored completely, leading to stained or damaged installations and unhappy customers. On the other hand, the benefits of sealers can be oversold by manufacturers or distributors and are often misunderstood by contractors and end users.
With the exception of glazed ceramic, most porcelain tile and a select few natural stones, sealer is highly recommended to help preserve the beautiful appearance of newly completed work, when properly chosen and applied. Understanding the role of sealers and managing expectations is essential to ensuring their correct use and ultimate success.
Why Use a Sealer
Cement grouts, unglazed ceramic tiles and most natural stones have a high degree of porosity, meaning these materials absorb water along with any other substances upon contact. While none is bullet-proof, an intact sealer can help prevent staining from colourless minerals found in water, as well as highly pigmented items like wine or coffee.
All sealers are designed to create a barrier to contamination by blocking absorption. Of course, sealers are available in different levels of protection from economy to premium. If the objective is to repel dirt and mud and prevent common water-based stains, then a general water and stain repellent will work just fine. However, if food or exposure to harsh chemical and cleaning agents is a concern, or the goal is to provide the highest level of protection, then a premium water and stain repellent is required.
Selecting the Right Type
There are many different forms and types of sealers but by their nature, most fall into one of two categories: penetrating/impregnating or surface/topical. This is determined by whether they leave a coating on the surface of the material being sealed.
The various sealers may or may not change the appearance of the tile or stone and can be water or solvent-based. Some, such as many solvent-based sealers, may have odours and fumes that can require special precautions and steps for safe usage. Testing tile and stone, both sealed and unsealed, with contaminants common to the area of installation is also important to choosing the right sealer.
Application comes down to the specific stone or other material plus the location of the installation and likelihood of staining agents. Natural stone that is outside and exposed to the elements, grout in a public location like a school or transit station, and tile in a restaurant are all examples of materials that are going to come into contact with contaminants on a regular basis.
Be sure to follow the manufacturer’s recommendations for the number of applications based on the tile or stone’s absorption and overall square footage. Highly porous tile or stone naturally requires more coats to obtain the full benefit of sealing. Otherwise, the sealer is stretched too thin and adequate coverage and overall stain resistance is not achieved.
Sealers will need to be reapplied over time, with frequency depending on the installed material, its location and usage conditions, and the type of sealer originally employed. Highly porous stone, exterior or highly exposed positions, and topical (versus penetrating) sealers may all require more frequent reapplication.
The cleaning regimen and products used will also affect the longevity of the sealer. Harsh household or commercial cleansers can strip sealers and damage the assembly. Always use a pH neutral cleaner designed for tile, stone and grout. The end user should periodically test for water penetration during routine cleaning; if the surface darkens, demonstrating water absorption, it is time to reseal.
Rod Sigman is the business development manager for technical installation and care products at Custom Building Products. Ron has worked for the company for nearly 30 years supporting Aqua Mix in various roles, including training and education for national accounts, job inspections, product specifications, and product research and development. He is also a frequent speaker at trade shows like Coverings, Surfaces and Total Solutions Plus.