Instructions on How to Lay Slate Floor
Slate flooring is available in various sizes, colors and finishes. Since slate is fairly brittle, you must lay it over a firm, flat surface. If you plan to lay tiles over a wooden floor, prevent sagging by first covering the subfloor with a layer of concrete backer board. You must fill in low spots in concrete subfloors with a self-leveling compound and trowel them smooth before laying slate flooring. Measure first and choose a tile sized to fit against the longest wall, so that the cut tiles at each end are at least half the width of a full tile. Does this Spark an idea?
Things You'll Need
- Pry bar
- Vacuum cleaner
- Steel measuring tape
- Pencil
- Chalk line
- Wet saw
- Circular saw fitted with a masonry blade (alternative)
- Modified thinset mortar
- Plastic concrete mixing tray
- Notched trowel
- Plastic tile spacers
- Mini hacksaw
- Slate tiles
- Spirit level
- Rubber mallet
- Colored sand based grout
- Point trowel
- Rubber grout float
- Sponge
- Bucket
- Finish nails
- Hammer
- Nail set
- Wood filler
Instructions
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1
Pry the skirting board away from the perimeter walls carefully with a pry bar and place them in another room. Vacuum the floor to remove loose dust and debris.
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2
Measure and mark the center point on the longest opposing walls with a steel measuring tape and a pencil. Stretch a chalk line between the points and snap a line down the center of the room. Mark a small vertical line on the starter wall with a pencil to act as a guide for your first tile once, you've covered the chalk line with thinset. You will be laying the tiles from the middle of the floor outward so that the cut tiles against the side walls are the same width; the chalk line will act as a guide when starting each new row.
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3
Lay out your first row of tiles a few feet away from the longest wall farthest away from the entrance. As you dry-lay the first row out, mix and match colored tiles to achieve a random look. Measure and cut the end tiles to size, either with a wet saw or with a circular saw fitted with a masonry blade. Allow enough room for a tile spacer to fit between the end tile and the wall.
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4
Mix a useable amount of modified thinset mortar in a plastic concrete mixing tray. Follow the instructions printed on the paper sack. Mix thoroughly with water to the consistency of thick cookie batter.
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5
Start at the middle and work your way outward. Pour out a line of thinset mortar stretching two tile widths on either side of the center line. Use a notched trowel to spread the layer of thinset the width of a tile evenly across the floor. Hold the trowel at a 45 degree angle. Scrape the teeth of the trowel against the floor and work the thinset into an overlapping semi-circular pattern. Maintain contact between the trowel and the sub-floor at all times to ensure correct mortar thickness.
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6
Cut one of the legs off a cross-shaped plastic tile spacer with a mini hacksaw. Place the spacer against the starter wall with the remaining leg exactly in the middle of the pencil line previously marked on the wall.
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Bed a second tile spacer into the mortar on the inside corner edge of the first tile to be set; straddle the center chalk line exactly with the spacer. Set the first slate tile with its left edge lined up with the spacers and the back edge butting against the inside leg of the T-shaped spacer against the starter wall. Rock the tile gently to bed it in. Place a spirit level on the tile and set it level in each direction by tapping the surface down with a rubber mallet.
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Place the second tile to the left of the center line; place its right edge against the plastic corner tile spacer and the back edge against the cut wall spacer. Repeat the rocking motion and bed the second tile down level with the first tile, using the spirit level and rubber mallet.
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Repeat with subsequent tiles against the starter wall until you bed in the last tile of the first row. Cut T-shaped wall spacers to use against the starter wall and use cross-shaped spacers to line up the inside tile edges as you work. Use T-shaped cut spacers to line up both end tiles correctly.
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Continue matching colors and laying rows of tiles. Separate each grout line with a spacer but stop at least 18 inches away from the wall nearest the entrance to allow for an exit walkway. Clean thinset mortar off the edges of the last row of tiles and off the floor.
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11
Wash the mortar tray and your notched trowel and stop work for the night. Allow at least 12 hours for the thinset to dry enough before walking on the floor to lay the final row or two of tiles.
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12
Measure and cut the end row of tiles if necessary but don't forget to allow room for the wall spacers. Mix up sufficient thinset mortar to lay the remaining tiles. Finish laying the floor. Allow 24 hours for the thinset mortar to dry thoroughly before grouting the floor.
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13
Mix up 30-minute supplies of fairly stiff colored sand-based grout at a time. Fill the gaps by forcing grout between the tiles with a point trowel held at a 45 degree angle. Fill the rest of the gap and smooth down with a rubber grout float.
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Allow the grout to partially set and wipe off all traces of excess grout with a clean damp sponge and a bucket of water. Rinse the sponge out frequently and change the water often. Take your time with this step; any grout left on the slate surface will be impossible to remove once it has dried out.
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Replace the skirting boards by attaching them to the wall with finish nails. Bed the heads of the nails below the surface with a hammer and nail set. Fill the holes with matching wood filler and wipe off excess with a damp sponge.
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Tips & Warnings
Wear knee pads for comfort while laying slate tiles.
Wear safety goggles when cutting slate.
A dark grout colored to complement the slate floor works well, and any traces of grout inadvertently left on the tile surface, will be less visible. Lighter grout tends to draw attention away from the natural beauty of the slate surface.
References
- Photo Credit David Sacks/Lifesize/Getty Images
