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Slate Tile FAQ

We are pleased to provide answers to some of the most Frequently Asked Questions (FAQ) on a wide variety of our products. For more information on our slate tile, please browse our selection of outstanding quality products or take a look at the answers to our frequently asked questions.

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Q. What is slate?

A. Slate is a fine-grained, foliated metamorphic rock that is formed when ocean or riverbed sediments are compressed and heated by the earth’s crust. It is composed mainly of clay minerals or micas, depending upon the degree of metamorphism to which it has been subjected. The original clay minerals in shale alter to micas with increasing levels of heat and pressure. Slate can also contain abundant quartz, along with small amounts of feldspar, calcite, pyrite, hematite and other minerals. Most slates are gray in color, and come in range of shades, from light to dark gray. Slate also occurs in shades of green, red, black, purple and brown. The color of slate is often determined by the amount and type of iron and organic materials that are present in the rock.

Q. Is BuildDirect’s slate tile suitable for the floor?

A. Yes, our slate’s durability and attractive appearance make it a popular choice for wide variety of uses, including flooring and flagging.

Q. What do both sides of the slate look like?

A. Slate has a natural cleft on one side from the split face and a machined (semi-calibrated) back on the other to manage thickness.

Q. How much does the thickness of slate tile vary?

A. Thickness of slate varies from edge to edge since the surface is defined by a natural cleft, having high and low points. Typically, thickness variation can be between 1/8” to 1/4″, depending on the format size. Slate tile is usually installed with a medium-bed mortar, which allows for the variation on adjoining tile edges to be minimized.

Q. How much extra material should be considered for installation?

A. It is recommended to order an additional 10% to 15% to allow for wastage due to thickness variation, cuts to fill corners, and the style of installation. Typically, 10% extra should be considered for square settings, and 15% for diagonal settings; even more should be considered if you will be creating special designs with the slate.

Q. How much do the dimensions of slate tile vary?

A. Though the sizes are given in imperial units, slate tile is cut to international metric sizes. Hence the actual cut size can be as follows: 12”x12” = 300mm x300mm, 16”x16” = 400mmx400mm, and 24”x24” = 600mmx600mm.

Q. Is slate resistant to damage?

A. Slate 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 may crack like any other tile. It is therefore very important to have an adequate substrate prior to installation. Slate is porous so moisture management and a waterproof membrane should be used when installing in washrooms and shower areas. Feel free to ask a BuildDirect Product Expert if you have any questions.

Q. What trowel size do you recommend for installing slate tiles?

A. Use at least a 3/8”x1/2” notch trowel for 12”x12” tiles, and a 1/2”x1/2” notch trowel (or larger) for 16”x16” and 24”x24“ tiles.

Q. Can I install slate tile outdoors?

A. Yes, slate tile can be installed outdoors, but please refer to each tile’s features for specific freeze and thaw information.

Q. Can I install slate tile outside on sand?

A. Slate tiles should not be installed on sand beds because they will crack and brake if not properly supported. Slate tiles should be set on a solid substrate with mortar. However, slate pavers can be set on sand beds; slate pavers from BuildDirect are 1 ¼” thick, and are designed to take heavier loads.

Q. Can I install slate tile on wood?

A. The only wood surface that is recommended for the installation of slate tiles is exterior grade plywood.

Q. How many defective tiles should I expect in my order?

It’s not unusual to have up to 5% of a slate tile order defective to some degree (e.g. chipped edges, cracked tiles, flacking, bowing etc.). Industry standards consider any amount up to 10% acceptable. These defective tiles can be used for cuts you will need to make during installation.

If your order contains more than 10% defective tile, please note it on the logistics receiving document and take photos. Please make a claim with us within 10 days of receiving your order.

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. How wide should my grout joints be?

A. It’s a matter of personal taste, but traditionally, slate tile is installed with wide grout joints to compensate for thickness variation. A 3/8” to ½” grout line is recommended, depending on the format size.

Q. What type of grout should I use?

A. Use a sanded grout for 1/8” to 1/2” joints, and saltillo grout for joints widths over 1/2”.

Q. Do I need to seal slate?

A. Slate is porous and can become stained. It is recommended to use a sealant so that stains can be easily extracted.

Q. Is there a PEI rating for slate tile?

A. PEI ratings are 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 tile. However, slate is very durable, and can be used where a hard-wearing product is required.

Q. After I receive my shipment, what should I do when I am ready to install?

A. 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 tiles 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 a BuildDirect Product Expert if you have any questions.

Q. How does buying slate tile from BuildDirect work?

A. BuildDirect works closely with suppliers from around the world to provide you with top quality slate at unbelievable prices. We fill slate orders in two ways. The first is selling pallets out of warehouses located throughout North America. The second is shipping container orders directly from select manufacturers and delivering them to your job site. Call a BuildDirect Product Expert toll-free for more information at 1-877-631-2845.

Q. Can I purchase just one box of tile before I place my full order?

A. We’re unable to sell individual boxes of tile due to shipping costs. The cost to safely ship one box of tile can be more than five times the amount of the actual tile.

To see our tiles in person before you buy, check out our free sample program. We’ll send you up to five free samples right to your doorstep. No credit card required. Also, we offer a 30 Day Money Back Guarantee, which means if you aren’t completely satisfied with your tile prior to installation, you can return it for a full refund within 30 days of delivery.

Q. How much slate tile does a container hold?

A. Container quantities of slate tile range from 5,000 sq. ft. to 8,000 sq. ft., depending on the tile size and destination. Slate paver container orders will have a maximum of around 2,500 square feet. A BuildDirect Product Expert will happily help you determine the container quantities permitted into your area.

Q. How do I obtain slate tile samples?

A. If samples are available for the product you are interested in, you can request a sample directly from our website. We will send you up to five free samples with no credit card required. Slate tile sample pieces are approximately 4”x4”.