Stone facades have different parts, one of these parts is the harness or scope that connects the facade cover to the back of the band.
Different types of stone scooping methods
The curbing or scoping of the facade is done by 2 methods: prefabricated scopes and wire or wire scopes, which we will describe below.
Prefabricated restraints
As the name of this category of scopes suggests, in this method prefabricated metal parts are used to restrain the facade. Pre-made scopes are divided into several groups, which we will describe each one below.
Sengnama scoop by biting method
This method, which is implemented to restrain the face stone in restrained faces (dry face), each of the face stones is directly connected to the supporting wall to bear the gravity (weight of the face) and lateral loads. The gravity load of each part of the stone facade is transferred to the back wall by two supports, which include supporting pieces.
Stone-faced scope by wire method
In this method, galvanized wires are used to restrain vertical stones, which are created in the grooves created on the back or side of the stone. According to publication 714, the diameter of wire scopes is 4 mm in external views and 2 mm in internal views. Unfortunately, in some buildings, the builders use ordinary wires instead of galvanized ones, and due to the corrosion of these wires, there will be a possibility of the facade falling.
Scoop of stone facade by two-stage method
In this method, the galvanized metal parts, which are prepared and purchased as follows, are attached to the back of ceramic or stone by two-component glue or stone glue, and these scopes are attached after hardening and implementing the stone and ceramic parts with the mortar behind the facade. be. But due to the fact that these scope parts are only attached to the facade with glue and the glue can also be separated from the back of the facade due to weather changes, this method of fastening is not recommended for stone parts.
Stone facade scope using the tripod method
The method of implementing three-legged scopes is the same as the two-legged scope, and it is still not recommended to use this method to control the facade.
stone face scope with butterfly method
Butterfly scopes are another method of prefabricated scopes that, due to the speed of its implementation, many employers and contractors tend to use this method in their projects.
Procedure
In this method, to install the scope parts on the back of the facade, grooves with an angle of about 45 degrees should be created behind the stone, and after cleaning the grooves, we pour a little stone glue in it and place the scope inside the groove.
The important point here is that, unfortunately, many contractors and builders do not believe in using stone glue and implement it without glue. But due to the low thickness of the facade stones and as a result the low depth of the created grooves, it seems necessary to use glue for a better connection between the scopes.
The scope of stone face by Z method
The z scope, like the butterfly scope, is included in the category of prefabricated scopes, and due to the dimensions of its prongs, this method is used for smaller pieces of stone and with less abrasive mortar. The method of performing this scope is exactly like the butterfly scope.
The scope of the stone face by the method of gluing a rectangular piece of stone to the back of the face stone
In this method, a piece of facade stone is glued to the back of vertical facade stones with stone glue. But as mentioned earlier, due to the expansion and contraction of the air, the stone glue loses its adhesive property and leads to the fall of the facade stones. Therefore, it is recommended not to use stone glue as the main connection of the scope to the facade stones.
Stone-faced scope by screw and dowel method
Unfortunately, the issue of curbing the façade is not taken seriously by the contractors and builders, and it is seen in some cases that they stop scoping the façade for various reasons such as: Low wages, time consuming, and the fact that this type of stone does not need a scope due to its porosity, and they refuse. In these cases, the building should not be finished until the curbing of the facing stones after installation is ensured.
The solution seen in publication 714 for the scope after installing the stone is surface restraint or screws and dowels. These braces are in the form of screws and their main use is as a reinforcement for stones whose braces are damaged or executed facades that lack braces at all. In this case, holes are created on the facade stone and it is restrained to the supporting wall by the opening screw (screw and dowel).
Important points: Screws and dowels should be at least size 6 or 7. If the back of the facade is empty, replace the holes.
Mouse tooth scope
In smaller pieces of stone, where it is not possible to run a wire scope lengthwise, this method can be used to restrain facing stones. This method is especially used in Roman facades
Transverse wire scope
According to publication 714, every 0.2 square meters of facade should be restrained. For this purpose, the distance of the grooves created for the implementation of the scope must satisfy this case. For example, in facade stones with a width of 40 cm, we must restrain the length of the stone every 60 cm. In some cases, to provide this opinion, the facing stones can be scoped transversely.
Wire scope details
The grooves created with an angle of about 45 degrees, the length of which is at least a millimeter apart from the surface of the facade.
Wire scope: diameter 4 mm on the outside and 2 mm on the inside
Tail of the scope: The wire of the scope at the junction of its two ends should be 15 cm long so that the scope is sufficiently engaged with the mortar behind it.
Auxiliary bite: We place a piece of facing stone between the scope wire and the back of the stone to make sure that the scope wire is fully inserted into the facing mortar and a sufficient connection is created.
The reason for using a scope or curbstone
According to publication 714, the need for the scope of facade stones can be expressed as follows: “Glazed facades are weak against out-of-plane forces and in order to withstand lateral loads such as earthquakes and wind, which cause the facade stone to come out of the facade wall and be thrown.” It goes out of the screen, the appropriate harness (scope) should be used. In the veneer wall system, the role of the mortar or adhesive material, the bearing of gravity loads (the weight of the facade) and the role of the scope or harness are also as a support and will not have a bearing role.
Advantages of using a tensile scope
Stretching scopes are also included in the category of prefabricated scopes and can be said to be the same as butterfly or Z scopes; with the difference that both parts of the opposite scope are restrained to each other by a long screw and it is not possible to separate these parts. This scope is excellent in terms of strength; But unfortunately, due to the time-consuming nature of its implementation, it is used in fewer projects than butterfly and Z scopes.
The equipment needed for grooving for the scope
In order to perform the necessary groove for the scope of the facade, according to the material of the facade, a stone or granite cutting board is needed, as well as an electric milling machine and personal protective equipment such as goggles and gloves.
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