The Content Of The Article:

Imitate a stone facade with a hand-carved coating and tinted on the surface, it is the bias to renovate this small extension. An aesthetic solution, easy to implement and very economical.

How to apply a coating to imitate the stone

Difficulty, cost, time and equipment to make a trompe-l'oeil coating

Difficulty: 2/4
Cost: € 7 / m2
Time: 2 days (for 5 m2 about)
Equipment: masonry scissors, triangular scraper, plastering blades, painter's knife, paint roller, thumb brush, skate and push brush, trough, upholsterer's roller, natural sponge, spirit level, painter's blanket...

A relief decoration, carved and painted

To renovate the facade of this small apprentice at a low cost, the choice was made of a process consisting of creating a "false stone cut" decoration imitating staggered joint stones.
Realize this decoration in relief, carved with plaster and painted with acrylic colors, requires a good knowledge of the techniques of coating and a small turn to handle blades to be coated, brush to rechampir and brush to skate.

Ancestral technique

The realization of the joints requires special attention because of them depends a natural and realistic result.

The preparation of the support must be neat.
If the plaster is very dirty, cleaning with a high-pressure cleaner is necessary.
The application of a printing layer makes it possible to block the fund to prevent them from flaking and eventually cracking (Beissier, Sikkens, Guittet...).
The thickness to imitate the stone is obtained by mixing an exterior filling plaster and a thin plaster, mixed with water (Prestonett, Toupret, Semin...).

A calepinage to heal

Then you have to draw the plan of the composition with the different dimensions of the false stones and the shades of color envisaged. The average dimensions of the blocks created are 40 x 20 cm.
To postpone the layout on the facade, you must first draw parallel horizontal lines (20 cm spacing) and offset vertices half a width, every other row, to imitate staggered joints.
The finishing work consists of applying an acrylic paint (ivory color) to the roll or, as here, to use acrylic paint tubes (Pébéo, Lefranc Bourgeois...) applied to the brush.

1 Support preparation

1 Support preparation

Scrape the old plaster with a stiff breather blade that removes all that sticks badly.

Clean cracks

Clean cracks

Open the cracks with a triangular scraper.
Scrape around to check that the plaster adheres.

Eliminate all residues

Eliminate all residues

Dust the surface.
Insist on cracked areas to properly remove all residues.

Apply a print layer

Apply a print layer

Apply a generous layer of printing (acrylic) with a short-haired drip roller.
Cross the passes to promote the penetration of the product in the support.
Leave to dry for 6 hours.

Mix filling and smoothing coats

Mix filling and smoothing coats

In a trough, mix the two powder coatings (filling and smoothing) in equal parts, to obtain a homogeneous paste (type bread dough).

Apply, let dry, sand

Apply, let dry, sand

With a large coating knife spread a coat of plaster (max 1 cm).
Leave to dry for 12 hours.
Sand lightly with medium-grit sandpaper.

2 Tracing stones and applying the plaster

2 Tracing stones and applying the plaster

Identify and trace the location of the fake stones.
Use a spirit level to control the horizontality of the tracings relative to the ground.

Draw with masking tape

Draw with masking tape

Just above each path, position strips of masking tape.
Opt for a ribbon width that corresponds to those of the joints (about 2 cm).

Adhering the ribbon

Adhering the ribbon

To promote tape adhesion, pass a caster wheel (wallpaper) onto the strips by pressing firmly.

Create fake stones

Create fake stones

Using a painter's knife, apply plaster pads to create the "stones".
Play with the thicknesses to obtain material effects and start the worksite from above.

Sculpt irregular stones

Sculpt irregular stones

Spread the plaster with a plaster (blade 20 cm wide).
Vary the pressure of the tool in order to carve irregular stones of uneven size.

Brush the plaster

Brush the plaster

Let the plaster draw, then with a brush to pat, tap, stone by stone, to create a material effect.

Crush with a plaster

Crush with a plaster

Crush the material slightly and unevenly, with a coating blade barely moistened and held parallel to the support.

Remove the masking tape

Remove the masking tape

Leave the coating and, while it is still cool, carefully remove the masking tape, parallel to the surface of the wall to avoid damaging the coating.
Leave to dry for 6 hours.

Sand the edges of the stones roughly

Sand the edges of the stones roughly

Sand the edges of the "stones" with medium-grit sandpaper (# 100).
Do not focus on imperfections; leave some small holes to imitate the natural and irregular appearance of the stone.

3 Painting the trompe-l'oeil coating

3 Painting the trompe-l'oeil coating

Prepare the colors (acrylic tubes) on a palette: mix the yellow ocher and the red ocher with a tip of ivory black, then add some white.
Mix 2 to 3 colors at a time to obtain a dominant ocher.
4 tubes of 37 ml and 250 cl of water cover about 20 m2.

Dab with an inch brush to rechampir

Dab with an inch brush to rechampir

From top to bottom and stone by stone, dab with a brush (or brush) thumb rechampir: make small zigzag gestures, well supported and without smoothing.
Avoid overflowing joints.
Thoroughly unload the brush before each restart.

Erase brushstrokes

Erase brushstrokes

Pass the brush to skate on each colored "stone", by pressing well on the support to eliminate the traces of brush strokes to rechampir.

Wipe with sponge

Wipe with sponge

On areas where the gesture was too much, do a light "wiped" with a piece of natural sponge slightly wet to restore transparency to the color.

Use an acrylic finish

Use an acrylic finish

On all joints, apply with an inch brush an acrylic finish, here your eggshell.

Supplies for exterior trompe-l'oeil fake stones

• Filling plaster
• Coating end of smoothing
• Acrylic print paint
• Acrylic paint (yellow ocher, red ocher, ivory black, white)
• Masking tape
• Medium grain sandpaper


Video Instruction: Parex Stone imitation Series Application