Stone imitation

PROMPT natural cement by Vicat, applied as plaster or finishing layers on soft, medium, or hard substrates, can replicate the appearance of natural stone. This process offers a wide range of possible outcomes. The use of PROMPT natural cement provides numerous choices in terms of :

• Shapes: Stone imitations can be adapted to harmonize with the nearby buildings and landscapes.
• Colors: The natural color of the PROMPT natural cement plaster is naturally ochre. It's possible to modify this color by adjusting the sand color or by adding natural colorants such as yellow ochre, reddish-brown earth, raw sienna, etc. The addition of lime to the PROMPT natural cement plaster can also lighten the mixture.
• Textures: The texture depends on the chosen surface treatment that best imitates the original stone appearance. Surfaces can be smoothed, scratched, textured with a sponge, swept, brushed, cut, etched, or bush-hammered.

The technique of stone imitation using PROMPT natural cement is rapid and cost-effective compared to using real stone. PROMPT natural cement by Vicat is a durable solution that allows for quick application. Other advantages include the ability to create imitation stones and the breathability of the wall due to the permeability of the plaster.

 

Technique

Before you start imitating stone with PROMPT natural cement plaster, it's essential to prepare the substrate. Depending on its nature, specific care should be taken.

• For cornerstones, quoins, and rectilinear stones: outline the layout and place guidelines
• For aged stone appearances: pre-sketch the desired contours on the substrate and set markers
• For older substrates: identify hollow areas, clear them, clean, and potentially apply a scratch coat of PROMPT natural cement before plaster application
• For smooth substrates: roughen or apply a bonding primer. The substrate should be damp

Once the substrate is ready and the mortar prepared with an appropriate mix (PROMPT natural cement, sand, TEMPO retarder, water), proceed with application.

It's advisable to work stone by stone. Apply the PROMPT natural cement mortar with a trowel or float to a thickness of 1.5 cm on a new substrate.

In the PROMPT natural cement mortar, mark the joints using a tool (such as the pointed end of the trowel) and then firmly compress the plaster. Check the overall aesthetic and either finish the joints or cut and potentially hollow them.

Finally, treat the surface as desired. For a natural stone appearance, uniformly scratch the entire surface. For a dressed stone appearance, leave a 1-2 cm margin around the edges that will be smoothed.