Slate Tile FAQ
- What is slate?
- Is your slate suitable for the floor?
- What do both sides of the slate look like?
- How much does the thickness of slate vary?
- How much do the dimensions of each slate tile vary?
- Are there drawbacks using slate compared to ceramic or porcelain?
- Is there a PEI rating for slate?
- Does MJ Flooring do tile installations?
- When I receive my shipment, what is the first thing to do when I am ready to install?
- Can slate tile be installed outside on sand?
- Is slate resistant to damage?
- What trowel size do you recommend for installing slate tiles?
- Can I install my slate tiles on wood?
- Which type of mortar should I use to install slate on exterior grade plywood?
- What does the acronym ANSI stand for?
- How wide should my grout joints be?
- What type of grout should I use?
A. Slate is a fine-grained metamorphic rock. It’s main constituents are quartz, chlorite, mica & calcite. Slate is formed when ocean or riverbed sediments are compressed and heated by the earth's crust.
Q. Is your slate suitable for the floor?
A. Slate is a very durable and hard wearing product and is suitable for use on the floor.
Q. What do both sides of the slate look like?
A. The back of the slate tile has been machine to either a flat or grooved finish, depending on the factory of origin. The top is a natural-split face surface.
Q. How much does the thickness of slate tile vary?
A. There can be up to 1/4" difference in the heights on the top surface of a slate tile. The nominal thicknesses are as follows:
- Chinese Slate Tile
- 12" x 12" : 3/8” - 7/16”
- 16" x 16" : 1/2" - 9/16”
- 24" x 24" : 9/16” - 3/4”
- Indian Slate Tile
- 12" x 12" : 3/8” - 7/16”
- 16" x 16" : 7/16" - 1/2”
There will be some variations beyond this range, but the product is fairly consistent. Slate tile is usually installed with a medium-bed mortar, which allows for the variation on adjoining tile edges to be minimized. Please order an additional 10-15% to allow for waste, cuts, and thickness variation.
Q. How much do the dimensions of each slate tile vary?
Slate tile is cut to Metric sizes - the Imperial sizes quoted are purely nominal measurements. Tiles sizes will be as follows. Indian Slate: 12"x12" - 300mm (+/- 1mm), 16"x16" - 400mm (+/- 1mm). Chinese Slate: 12"x12" - 300mm (+/- 3mm), 16"x16" - 400mm (+/- 3mm), 24"x24" - 600mm (+/- 3mm)
Q. Are there drawbacks using slate tile compared to ceramic or porcelain tiles?
A. Slate tile does need a little more in the way of maintenance compared to ceramic or porcelain tile, but its unique qualities and appearance are often preferred to man-made products.
Q. Is there a PEI rating for slate tile?
A. The PEI refers to ratings set by the Porcelain Enamel Institute. These ratings were developed for the Ceramic and Porcelain tile industries. There is therefore no PEI rating for slate. However, slate is very hard and durable and can be used where a long-wearing product is required.
Q. Does MJ Flooring do tile installations?
A. We do not do tile installations. Please consult your local Yellow Pages for information on tile setters.
When I receive my shipment, what is the first thing to do when I am ready to install?
Be sure to check all contents of the pallets prior to installation. Any claim will be void if the natural stone has been installed.
With all natural stone applications, it is highly recommended that the installer avoid choosing tile for an installation on a “one pallet at a time” basis; the best method is to open boxes in all pallets from the start. Each tile from each box will be varied from pallet to pallet and an installation should incorporate the contents of all pallets evenly during an installation. This method will more effectively address the issue of color variation, which is a reality when working with any natural stone product. Please contact your sales rep with any questions.
Q. Can slate tile be installed outside on sand?
A. Slate tiles can be used outside if set on a solid substrate with mortar. Slate tiles should not be installed on sand nor should they be used as pavers. Slate pavers from MJ Flooring are designed to be set on a sand base (they are 1 ¼” thick)
Q. Is slate resistant to damage?
A. Slate (and any other natural stone that we offer) is highly resistant to damage, as long as it is applied to a solid substrate. If the sub-floor prior to the slate installation is flexible (for example, a thin plywood sub-floor), the slate could crack like any other tile. It is therefore very important to have an adequate substrate prior to installation. If in doubt, you should consult a professional installer about this.
Q. What trowel size do you recommend for installing slate tiles?
A. Use at least a 3/8"x1/2" notch trowel for the 12"x12" tiles and a 1/2"x1/2" notch trowel (or larger) for the 16"x16" and 24"x24 ".
Q. Can I install my slate tiles on wood?
A. The only wood surface that is recommended for the installation of tiles is exterior grade plywood.
Q. Which type of mortar should I use to install slate on exterior grade plywood?
A. Use a mortar that complies with the ANSI A118.4 (latex or acrylic modified mortar).
Q. What does the acronym ANSI stand for?
A. American National Standards Institute.
Q. How wide should my grout joints be?
A. It's a matter of personal taste, but traditionally slate tile has been installed with wide grout joints. We suggest 3/8" for the 12"x12" and 1/2" for the 16"x16". Due to slight variations in tile size use of tile spacers is not recommended with slate tile.
Q. What type of grout should I use?
A. Use a sanded grout (1/8" to 1/2" joints) and use a saltillo grout for joints widths of 1/2" to 1 1/4".
