Ways to perform limestone fixing
Limestone (CaCO3) is calcareous sedimentary rocks which is formed at the bottom of lakes and seas with the accumulation of shells, bones and other calcium rich sources. The organic matter that sets down in seas and lakes is preserved as fossils. Over time span of millions of years, layer after layer is made-up accumulating weight. A chemical reaction is caused by the heat and pressure at the bottom of the sea surface, that creates sediments and turns into solid stone — the limestone.
Limestone can be damaged by age, neglect or heavy use. Stains of Alkali can cause discoloration when alkali-charged moisture permeates the limestone from its bottom bed. Efflorescence can occur when wetness catches the sulfates of sodium, calcium, magnesium, iron or potassium from within the wall. This can come up with the formation of a whitish powder on the stone’s surface, flaking and exfoliating.These issues can generally be corrected by a professed service such as honing and polishing. Limestone Restoration utilizes an array of cutting-edge methods and products to restore the shiny lustre of the surface.
Acid-charged moisture can cause more severe damage to the limestone surfaces. Over years, acid rain can break down the softer, more porous and chemically sensitive limestone veneers. Since limestone is less resistant to damage from oils, acids, alkali or other chemically charged liquids than marble and granite, it requires larger sections to be replaced during Limestone Restoration.
A limestone restorer uses following major ways to handle damages caused:
1) 3D imaging: It duplicates three-dimensional surfaces using computer-driven, laser-scanning process that allows for three-axis dimensions. Once the subject is scanned, the computer co-joins the scans to create a 3D surface. Where there are areas of missing stones, technicians recreate the missing pieces. Depending on the job and the machine used, the process yields a semi-finished product ready for hand finishing. In some cases, a completely finished piece is ready to replace the damaged one.
2) Photo reproduction: It is used where sample sections are missing. The damaged sections then may be restored using on old photographs of the limestone before it was destroyed. Skilled artists capture the image, adjust the dimensions to actual size, and convert the data to a 3D model on the computer. This 3D model is used to generate the machine code to feed to the CNC cutter. The CNC cutter creates a replica of the original section of missing stone.
3) Tracing: Restorers take traces of the left over pieces of the original stonework and transpose the designs to fit into missing sections of the structure. The drawings are then converted to a 3D model and then programmed as machine code into the cutter. Once the cutter’s job is done, artisans adds any finishing touches, and the substitute piece can be installed in the missing section.
4) Smaller repairs: Chipping is common performed on older stone structures. To repair tiny chips, special mortars are applied and then sanded, and, then painted to match the surrounding stonework once the repair has set. Limestone Restoration experts have to be careful to avoid adhesives and mortars that will degrade the surrounding limestone.