They are because the sand and cement mortar behind the rock penetrates into these holes and prevents it from being separated from the facade. These rocks can be named travertine stones. Some rocks are silk or marble or marble or stone. And all kinds of Chinese stones have a smooth surface and, as the stone is not very suction-resistant, it adheres well to the façade and may detach and fall off after a while. A special so-called scoop fastened to the wall
Reasons for separating stone from building facade
One of the materials that is nowadays abundant in the facades of buildings is a stone that makes the building heavy and architecturally and aesthetically solid and gives meaningful identity to the city's buildings. It is dirty later than other materials and easier to clean than other materials.
In the case of facade rocks, the thermal expansion coefficient of different rock minerals as well as the mortar behind it should be within a range to prevent crushing and detachment from mortar.
Rock resistance due to various factors such as cold weather, heat, and fire is constantly changing. In metropolises, the presence of gases such as so2 o2 and co2 can be one of the factors related to chemical weathering that is abundant in the air and the rocks under construction more Their effect loses its resistance. Some physical factors such as freezing and thawing inside the cavities affect the rock.
It should be noted that chemical and physical weathering agents work together and often cause discoloration and breakage of the stone.
Also, performing indoors and outdoors with people not trained in traditional materials can also be one of the reasons for stone removal and the amount of porosity due to the penetration of rainwater into the stone cavities, these cavities often themselves. Due to the chemical effects of natural solutions on some minerals in the rock, they are frozen in the zero-degree air of winter that penetrates into the rock pores, causing major cracks in the rock. Increased over time to cause all or part of the rock to fall, strong earthquake force can also be One of the important reasons is that the direct relation of the earthquake lateral force to the weight of the buildings due to the difference of thermal transfer coefficient as well as the difference of expansion and shrinkage of the mortar part behind the stone compared to the exterior materials themselves and the existing stiffness part. It is noticed that over time the stones are not too long apart and even the wire scopes do not prevent them from falling.
There are pores and pores on the surface of some facade stones, which are very suitable for installation because the sand and cement mortar behind the stone penetrates into these holes, preventing it from being separated from the facade. Named Travertine Stones Named Some rocks such as silk and marble or marble or stone and all kinds of Chinese stones have a polished surface and may stick well to the face as the stone is not very slippery. To prevent this from happening, you have to prevent them from falling behind with special rods They say the scopes are fastened to the wall
Most have seen buildings that used marble on the facade less than 5 years later, with environmental and climatic conditions such as the city of Tehran deteriorating over time due to existing calcareous filaments. It is in marble that is exposed to cold and warm weather by rain and other weather conditions, leaving the cement mortar bed and falling to the ground to add limestone in areas with high rainfall and carbonaceous gas in space. Too much is not suitable for the exterior of buildings
Granite stone due to its hardness and low porosity, low porosity behind the stone and very low water absorption for installation with cement and sand mortar alone is an unprofessional and problematic task because slurry is well incorporated. That is why there is usually not enough adhesion between the stone and the slurry. This causes the stone to be separated from the mortar for less than a year and to be removed from the facade. This form of granite is largely eliminated by clamping and blocking the granite. To be
If this is done by slitting the stone and wrapping it with galvanized wire before slurrying it is called a scoop. Another method is dry installation which has different details and is very common today.