Dowels for concrete: types and installation

Dowels for concrete have become widespread as a fastening base for the use of screws and anchors. Such elements are classified into types according to the strength of concrete, since the reliability of fastening depends on their quality. The concrete base can be heavy and light (porous), while the latter is characterized by low resistance to compression, and heavy - on the contrary, for this reason it can be under pressure for a long time.

Characteristics

The principle of the dowel has a similarity to the wedge. On the body there are antennae, located opposite the back stroke, due to this it can not be pulled out after mounting in the wall. The final and complete fixing comes after the screw is inserted into it. Due to wedging, the fastening is securely held in the wall for many years.

The material used to make the dowel depends on the mass of the object requiring fastening. Dowels for concrete plastic are suitable for designs of small sizes, for example, furniture. Steel variants are used for more impressive objects, their working principle is similar to a plastic element.

Scope of use

The purpose is to fix sanitary ware, pipelines, electrical equipment. It is necessary to pre-drill a hole of a suitable size, which is noted in the instruction manual, cleansing from fine dust, only then insert a dowel and an anchor.

If you need to hang a heavy load on the concrete base, the maximum diameter of the screw is used. It is important to observe the ratio of the length of the dowel for a specific operational load and the correct selection of the fasteners themselves, since they must be somewhat longer.

Yesterday and today

Before the invention of such devices, a "cork" made of wood was used. It was inserted into a dry hole, or smeared with glue, cement mortar or alabaster. This design was not distinguished by its durability and reliability, in view of the shrinkage of the mortar and drying of the tree.

At present, high-quality plastic (for example, polyethylene) or steel in combination with supporting parts (self-tapping screws, nails and their variations) with a resistant coating preventing corrosion, or made of stainless steel is used to manufacture the dowel for concrete.

The dowel-nail is the simplest option. Unlike standard nails, a screwing method is used to install it.

Classification

By the method of use, all elements are divided into two groups. Standard dowels are inserted into drilled (drilled) holes in the base without fixing structures.

Due to the fact that this technique is used only in two places of installation, due to the discrepancies between the holes of the part and the array, frame dowels are produced , assuming simultaneous development in the basis and design. This eliminates the possibility of mismatch.

Such variants have found their application in a wide range of works, but the greatest efficiency is noted in the installation of door and window boxes in hollow and solid bases. Also due to their use, there is the possibility of rapid dismantling while maintaining the same type of box.

Conventionally, the building dowel is divided into two groups for application:

• With the anchoring principle of fasteners for hollow and laminated wall structures;
• Expanding options for massive walls.

Universal fastening

A new system is being designed for use in industry and everyday life. It has acquired a wide distribution due to its distinctive technical properties, high processability and ease of use.

The chemical anchor Hilti is used for rod bearing parts of different purposes. A composite material made of synthetic, durable resins provides sufficient strength. Among the distinctive features, it is worth noting a significant increase in the quality of elements in the tensile and fracture. Chemical properties increase the quality of installation of steel products and outperform the standard options. Such results allow to achieve excellent adhesion of the core part and the base, with the solidified composition of the synthetic resin.

The chemical two-element anchor Hilt allows to fasten elements with a large weight on any concrete and stone planes. A high level of sealing is an added advantage. This plays a special role in operation in conditions of high humidity. Some types of substrates do not allow the formation of high-quality fastening of metal products with the help of steel or plastic dowels. This applies to loose building materials, among which is a natural stone, hollow brick and aerated concrete.

Dowels, designed for heavy loads, are made of metal alloys, and are equipped with threaded elements (bolts and studs). They are suitable for the installation of load-lifting hoists, garage doors, as well as sun awnings. In accordance with safety technology, metal versions should be used to fix the suspended ceiling, as in case of fire the plastic may melt, and there is a risk of a ceiling falling.

Elements for porous material can be mounted without drilling holes. The dowel for concrete and bricks easily enters the wall with a standard screwdriver due to the large thread on the outside and a point that is similar to a drill bit.

Butterfly

A characteristic feature is the construction. It is an indisputable element with longitudinal protrusions. The latter are necessary to prevent cranking. Also there is a stop board and folding fastening ribs. The ribs extend the plane of contact with the support, and the rim does not let fall into the available hole. This option has become widespread in the fastening of skirting boards, shelves and lighting elements. The standard dimensions of this type of dowels are 14x35 and 5x25 mm.

Dowel for foam and aerated concrete

Has high ribs, greatly increasing the area of connection of the hole and the element. This requires pre-production of holes.

Nylon classic dowels for concrete, the price of which starts from 200 rubles per 100 pieces, which have received the greatest distribution, allow you to get rid of the main part of the installation difficulties. They are suitable for any wall structure and are used with screws up to 15 mm in size.

The dowel is held in a hole of the appropriate diameter with the help of a barb, facing back, after the wedging is firmly held by the existing large teeth.

Also, the traditional elements are dowels used for aerated concrete. For them holes are drilled in accordance with their core diameter. Fasteners are hammered into the hole with a hammer, the retention in the base is provided by wedging the screw and the presence of ribs in the form of a spiral.

A distinctive feature of universal dowels is that when fixed to a hollow base they "calculate" the hollow space. An anchor dowel for concrete expands into the cavity and is fixed in it. When used in a concrete or brick base, it is firmly in contact with the walls of the drilled hole after unscrewing.

Features

Proper use of the dowel for concrete requires the selection of suitable drilling, installation equipment. During work, it is important to monitor the perpendicular direction of the drill to the material, while using a worn drill or not suitable for a specific substrate is prohibited.

The cut hole must be carefully cleaned from dust and debris. It is important that the depth and diameter match. Drills produced for the production of building materials of solid type, should not be used for plates and sheets. Works with aerated concrete are characterized by reaming of holes of smaller size, in comparison with the dowel itself.