The Content Of The Article:

Slate is a natural stone as resistant as granite. Its "old-fashioned" pose and its mother-of-pearl cabochons adorn the floor of this bathroom with character.

Slate floor

Necessary material

  • Underwater tile protection system (SPEC)
  • Primary hanging
  • Tile adhesive mortar and joint mortar
  • Natural stone paving (20 x 20 x 1 cm)
  • Tile waterproofing

Difficulty: 2/4
Cost: 75 € / m2 (not installed)
Time: About 3 days to two
Equipment: meter, square, chalk line, sponge, tiler tools (tile cutters, toothed trowel with 9 x 9 x 9 mm teeth, rubber mallet and squeegee, foam trowel...), trough, large bucket or washing machine, electric mixer (for rent)…

To coat the interior floors, the choice was long focused on polishing stones, so very smooth and easy to maintain: marbles and marble stones, granites, even some limestones. Most of these stones make up a continuous surface with poorly marked joints.
At this smooth aspect, one may prefer the grosser surface sandstone, or the marked relief of shale or slate, as is the case here. A choice all the more justified in a bathroom, where you move barefoot and wet.

Slate: a stone with many shades

In addition to its texture, slate is distinguished by its many shades of gray, which sometimes combines the orange of iron oxide. The result is a floor with a strong personality, here accentuated by an "old-fashioned" laying with square tiles arranged at 45° with crossed joints. Some of them, with two cut angles, allow you to insert mother-of-pearl cabochons that delimit the location of an island bath. Placed side by side, slabs and cabochons leave only narrow joints. They correspond to the slight splinters (wrinkles) that comprise the edges of the slabs.

Think about the tightness

The water can eventually seep through the joints of a paved or tiled floor. That is why a bathroom should at least receive a tiled water protection system (SPEC). This is usually a coating based on synthetic resins applied in two layers before the paving (Bostik, Cégécol, Weber...).
Although slate is not porous, it can stain. It is therefore advisable to apply a tile waterproofing after the installation (Casto, CerroRoc, Techniseal...). It facilitates routine maintenance with a neutral pH detergent diluted with warm water and then rinsed.

Plans for laying a diagonal cut

The installation starts along two perpendicular axes.
Determine the center of the room by drawing the diagonals. The basic tile is placed at their intersection.
Leave this point and lay a row of tiles blank. Depending on the fall at the edge, push back the starting line.
Perform the same operation in the other directions until you obtain a cut on the diagonal of the tiles (more or less half a square) along the least visible wall.

Lay diagonally in a rectangular room

Rectangular room

We manage to have more or less a half-square on the periphery, cut at 45° on the diagonal.

Lay diagonally in an irregular room

Irregular piece

The best is to leave a 45° cut along a wall, or two, on the most discrete part of the room.

Layout and gluing

Materialize the surface of the bathtub with a plastic sheet

The layout is made with respect to the future bathtub, here posited as an island.
Materialize its surface using a plastic sheet or cardboard.

Draw tile alignment marks

  • Lay the blank tiles to center the start of the installation relative to the bath, in the diagonal.
  • Draw the corresponding alignment marks.

Mix the adhesive mortar with a mixer

  • Mix the adhesive mortar (about 6 l of water per 25 kg bag) with a mixer (slow speed) until a smooth paste is obtained.
  • Allow to rest for 3 min and reshuffle briefly before application.

Glue the back of the tiles

  • Apply a layer of thin-set mortar on the floor.
  • Glue the back of the first tiles with a spatula with teeth (9 x 9 x 9 mm).
  • This double sizing (not mandatory) is a precaution because of the thickness of the tiles and the support.

Apply the tiles along the path

  • Apply the tiles against the chalk mark previously.
  • Make sure to leave an interval of 5 to 8 mm approximately flush with the wall. It will be masked by a plinth.

Press the tiles on the support

  • Press the tiles on their support with a back and forth motion to crush the furrows and avoid air bubbles, or by beating them with a rubber mallet.

Cutting and laying cabochons

Cut the cabochons

  • Use a cabochon to identify the corresponding cutouts.
  • Use a tile cutter or tile.

Check the accuracy of the cuts

  • Lay the 4 blank tiles to check the accuracy of the cuts: the cabochon must not prevent their edges from joining.

Draw new benchmarks

  • Moving away from the starting point, the risk of shifting increases: arriving at the center of the room, draw new landmarks.
  • Finish laying and wait at least 24 hours before grouting.

Grouting tiles

Fill the joints with the mortar

  • Start filling the seals opposite the door.
  • Use a foam trowel and, to save time, spread the mortar over several square meters.

Remove the excess mortar with the foam trowel

  • As soon as the first joints are filled, scrape the mortar towards you with the foam trowel to remove the maximum.
  • Wipe the residue with a damp sponge.

Selection of pavements

Marble stone limestone

Marble limestone (travertine) with hammered edges. Formats: 20 x 20, 20 x 40, 40 x 40 and 40 x 60 cm, ep. 12 mm. Highly nuanced beige-brown color, brushed look not capped. € 54 / m2. "Classico", Point P.

Contemporary slate tile

Contemporary slate floor tile. Size: 45 x 45 cm, thickness 10 mm. Indoor or outdoor use. 53 € / m². "Ref 67744131", Leroy Merlin.

Glazed porcelain stoneware

Imitation travertine.
Glazed porcelain stoneware with a very hard surface (7, according to the Mohs scale). Size: 60 x 60 cm, thickness 10.5 mm. Gray color. 38 € / m². "Vicenza", Castorama.

Glazed porcelain stoneware in the form of bars

Oxidized metal effect.
Glazed porcelain stoneware also available in the form of mosaic strips on weft with variegated hues. Size: 30 x 60 cm. Color copper or silver. € 28.50 / m2. "Allure," Lapeyre.

Yonne stone with irregular edges

Yonne stone with irregular edges, aged finish. Size: 20 x 20 cm, thickness 20 mm. Available in 7 other finishes (softened, peeled, bossed, bush hammered, chiseled, brushed and brushed). From 42 € / m². "Massangis 20 x 20 cm", Rocamat.

Ultra-resistant enamelled porcelain stoneware

For intense traffic.
Ultra-resistant enamelled porcelain stoneware (class PEI V), complemented by 8 x 33 or 40 cm matching skirting boards. Formats: 33 x 33 and 40 x 40 cm, ep. 7.5 and 8 mm. Color white, honey, beige. Starting from 27 € / m2. "Anjou", Alfacaro.
All prices are from 2015.

Video Instruction: Diagonal Pattern Tiling Tips - DIY Network