In the restoration of historical monuments, ancient structures, and decoration, it is frequently necessary to reconstitute deteriorated natural stones. Indeed, the dimension stones used for frames, cornerstones, or even decorative elements can deteriorate for various reasons such as freezing, pollution, or other climatic factors and the effects of time. This can lead to surface abrasions, fractures, detachment of the facing, loss of coherence, and crumbling.
Solution
After identifying the cause of the deterioration, an important step to ensure the restoration proceeds under optimal conditions and to prevent the stone from deteriorating again, natural PROMPT cement can be used to repair these natural stones. A 100% natural solution, natural cement allows for the complete reconstitution of the stone to its original state. It is an economical, aesthetic, and durable solution. The art of imitating local stone using PROMPT natural cement has existed for over 180 years.
Technique
Two approaches are then possible: using PROMPT cement as mortar or mixing it with lime, depending on the hardness of the stone. The repair mortar should possess mechanical strength, permeability, and flexibility comparable to the stone itself, as well as good chemical compatibility.
In this regard, varying the proportions and choosing the aggregates will allow adaptation to specific situations such as the restoration of window frames, doors, gates, porches, vaults, and common sections of walls.
Depending on the desired physical qualities and strength, different dosage choices can be made by varying the amounts of binders, lime, sand, and natural PROMPT cement.
We therefore recommend conducting several preliminary tests by varying the proportions. Note that the dosage will not be the same for hard stones and soft stones.
The use of Vicat's PROMPT natural cement can be employed for restoration work on ancient structures, decorative elements such as door and window frames, cornerstones, or exposed stones on walls. It facilitates the repair of soft stones like sandstone or chalk, as well as stones in aggressive environments, exposed to seawater.
The use of Vicat's PROMPT natural cement offers numerous advantages. The first is its naturally occurring ochre color that develops after a few days. This natural shade, particularly well-suited for historic substrates, allows for playing with the sand's color and its constituents like mica to create light effects. This ochre cement can be further modified by adding colorants, preferably natural ones like yellow ochre or sienna earth.
Other benefits include its permeability, elasticity, compatibility with stone, quick execution, and adhesion to all types of construction materials due to the fine texture of the cement. Beyond being a rapid-setting cement, another significant characteristic is its durability. Indeed, the mineralogical composition of Vicat's PROMPT natural cement grants it durability properties such as long-term strength development and resistance to aggressive waters and seawater.
