Do It Yourself Installation: Sealing And Grouting Slate Tile

Slate Tile installation can be tricky due to the naturally rough surface which must be cleaned, cured, and sealed. Learn what materials are needed to properly complete...

Slate tiles are created by splitting layers of quarried stone. For this reason Slate tile offers a durable and uniquely textured aesthetic to your finished product. While these characteristics are desirable in the long term, the nature of slate tile can present unexpected challenges during the installation process.

Whether your Slate tile is installed indoors or exposed to the elements, the choices you make in this initial stage will affect the entire life of your tiled surface. While the stone tile itself is remarkably durable in high traffic areas, the surface remains vulnerable to water penetration, as does the grout which joins each tile and completes the final visual effect. To protect your investment, not to mention your sub flooring, drywall, or garden path bed, choose the proper grout, and ensure that the entire surface is properly sealed to prevent water damage and/or erosion.

Once your slate tiles are in place, the next step is to apply grout to the spaces between the tiles. This stabilizes the structure of your tile installation and is your first line of defense against tile breakage. The grout you choose is also the second aesthetic element to your tile installation and will play a key roll in the overall visual effect.

Choosing the proper grout can be a challenge to rival a United Nations negotiation. The options seem to be without limit, and it is a challenge to receive a straight answer to any question. Here are a few key points to demystify the process:

The term "grout" refers to a finer, thinner version of the overall term "mortar."

Generally grout, or thin-set, as it is sometimes called, is used where the space between the tiles is 1/16" or less. In spaces that small, the thinner formula is an asset in the application, but the elements which remain behind when the water content has evaporated (or "cured") remain the same.

For between-tile spaces greater than 1/16th inch, the term "mortar" is used, and refers to the base formula which is thicker and more coarse in texture. Mortar is what is generally recommended for use between slate tiles, though the word "grout" may be used in packaging. Your best bet is to take a close look at what the recommended use is for each product, and pay close attention to added ingredients.

Grout comes in many pre-mixed shades designed to compliment a variety of tile choices. Specific grout colors can also be custom mixed at your request by a number or vendors, though the prevailing opinion seems to be that your best bet for a complimentary match is to obtain your customized grout from a vendor who carries the shade of tile you have already purchased.

Other additives, such as latex, acrylic or polymers, may offer attributes such as increased flexibility where the tiles themselves are inflexible. This can be of particular use in older homes, or homes built in climates where severe weather changes are a factor.

Having chosen your grout, the next step is to prepare the installed tiles. This should require no more than a thorough wipe-down with a lint-free cloth.

Still, you should keep in mind that you have chosen tiles with a textured surface, and there is no such thing as a schmear-free grouting job. You must be prepared to spend the time required to wipe all traces of grout from the tile surface before it has bonded.

There are products on the market designed to ease this process, and though they add a step to the overall project, they seem to ease the labor burden on your back and arms. These products are temporary, water-based surface coatings which can be put on the tiles and allowed to dry before you grout. This way, when you grout, any extra which would normally adhere to the tile, adheres to the water-based surface coating instead. This allows for a soap "˜n' water clean-up.

Allow surface to cure for twenty four hours.

The premise, now, is that the entire surface, both slate tile and the grout between, are ready to receive the sealant which you intend to use on the entire floor. Those of us who have actually completed home improvement projects, however, would like to do a quick test to make sure that all is well.

Grab a piece of unused, untreated, tile"¦ An extra tile, a broken scrap, anything will do. Dribble a few drops of water onto both the scrap piece, and the installed tile including a grout edge. Observe how the water is absorbed. If the water absorption on both pieces of tile and the grout are the same, you are ready to move on to the sealing process.

If the absorption rates are NOT the same, you will want to take these two precautionary steps"¦

First, use a product designed to break the bond created by the cement element of the grout. Thoroughly clean all tiles, being careful to come as close to the tile edge as possible WITHOUT coming into contact with the grout (which is supposed to retain its cement bond in order to be effective).

Second, particularly if you have used a grout with an acrylic or polymer additive, you will want to do a quick wipe-down of the entire surface, including the grout, with mineral spirits.

Now that you are ready to seal the entire surface, there are two types of sealant from which to choose: Surface Sealers, and Penetrating Sealers.

A surface sealant is designed to remain on the surface of both the tile and the grout, creating a protective covering which resists stains and seepage. It can be applied with either a clean sponge, or a brush, though you will want to be careful of the brush shedding hairs, as the hairs will mar the surface finish.

The advantage to this approach is that you can achieve a glossy surface to the raw stone if that is what you desire. Also, points of wear due to high traffic may be more readily apparent than with a penetrating sealant. Unfortunately, where you perceive a worn spot, it is safe to assume that the seal is no longer intact in that area. Reapplication may be necessary.

This type of product is applied to the surface and, though there are products designed to cure more quickly, should be allowed to cure over-night for best results.

You will need to test various areas when the finish has cured, and if even the slow absorption of moisture is observed, the surface is not sufficiently sealed. You must apply another coat, cure, and test again.

A penetrating sealant is designed to do precisely that, to penetrate porous surfaces and to harden inside, sealing the porous nature of the material. It should be applied with a clean sponge or lint-free rag.

The advantage to this approach is that the product does not create a glossy finish, but rather maintains the integrity of the "raw stone" appearance. Worn spots due to high traffic are not a concern because the seal is beneath the surface of both the tile and the grout.

Penetrating sealers are formulated to cure within a few hours, but high humidity climates should allow approximately double the time listed on the product label. Two coats are recommended to ensure a complete seal, and after 24 hours, the "water dribble" test should be repeated.

Both methods of sealer benefit from a light buff with a lint-free dusting cloth after they have cured completely.

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