Reliable fixation of objects of light weight on a monolithic wall is performed by a dowel for concrete, which can have a different design and method of adhesion in the hole. Certain types are allowed to be used in brick or stone walls. If it is planned to fix a more massive structure to the surface, then an anchor product is used, which is higher in cost, withstanding an increased load in relation to the traditional one.
Classically, the element consists of a plastic sleeve that has protrusions along its entire length to prevent twisting inside the hole. A metal rod is screwed into it, which takes on the weight load. The plastic has such dimensions that when assembled, the screw is bursting into the cavity. This view is easy to disassemble with a screwdriver.
Standard dowels for concrete surfaces differ from similar elements for brick. Due to the heterogeneity of the masonry, it is required:
- a bushing that is large in order to ensure that support points are found on all sides;
- increased length of a steel rod made in the form of a threaded stud.
A uniform wall will be able to firmly anchor a nail driven in by impact. It runs at half the length, which reduces installation time. In brick, it will produce great destruction, which will not ensure the strength of fixation for a long time. In the presence of a perforator, self-tapping screws are used in concrete without a dowel, when the metal screw enters directly into the drilled socket. The installation procedure is simplified and the cost of materials is reduced.
The type is selected according to the maximum possible load and the available tool. If in doubt, what is better to choose in your case, you need to study reviews of a similar experience on construction forums.
Classification
For work on concrete, it is customary to use the following fasteners, which can be bought in an assortment:
- universal;
- spacer;
- nail;
- butterfly;
- front;
- chemical.
Some of these types are designed for certain types of surfaces (special), for example. For solid concrete, the dimensions of the metal fasteners are 6x40 mm. Longer dowels for lightweight concrete will start at 6x60, 6x80 and have a maximum dimension of 10x160 mm.
1. Spacer.
This type confidently fulfills its function when installing rigid hinged structures. Differs in wavy shape and size of metal screws. Sleeves in the form of a cylinder have 2-3 spacers (spikes), which ensure reliable fixation in the socket. Installation is carried out with a hammer followed by screwing in a self-tapping screw.
2. Butterfly.
It is used for thin walls. The sleeve goes through the hole, the far end is tightened when the metal rod is screwed in, covering the concrete from 2 sides. The installed element is firmly fixed.
3. Universal.
Combined version of butterfly type spacers. This metal plug is designed for use on different types surfaces. Ideal for old, uneven walls, mixed surfaces, hand punching.
4. Nail.
On a solid base, objects are hung on a nail driven in with a construction gun or by hand. Such fasteners have various types of execution for concrete, rubble stone, brick, soft coatings such as GVP, chipboard.
The steel element is a thick bar. It is pointed at one end, thickened with a cap at the other, so as not to sink unnecessarily into the concrete. A lock washer is put on the galvanized body, which plays the role of a guide. Such a dowel is not fixed twice - it is needed when installing a structure with increased strength.
There is no need to work with a hammer drill for drilling holes, which significantly reduces the time of fastening and cleaning up debris.
5. Front views.
Used for the installation of thermal insulation cladding. They work according to the spacer type, but have increased dimensions (length, head Ø). The bushing and metal screw are made of impact-resistant materials.
6. Chemical.
Special fasteners for foam concrete. In the kit, you need to buy a container containing polymerizing substances that freeze in the nest, forming a dense zone in the porous structure. The process takes from 2 hours to 1 day.
It is intended to fix objects exclusively in aerated concrete. It features a wider thread that increases the area of engagement with the porous material.
Specialized fixing on polystyrene concrete wall blocks. The spiral sleeve works on the spacer. She is able to withstand significant loads. It is effectively used for hanging cabinets, shelves, hoods, heavy objects and household appliances.
9. Self-tapping screws.
The most familiar form, convenient for use at home, is self-tapping screws installed in a plastic dowel or directly in concrete. They can have a regular thread, a herringbone screw (cones nested in one another in appearance).
A change in the thread cross-section along the length of the rod indicates that it must be driven in without a spacer insert. This type is called Ø 7.5 mm. A standard 6 mm hole is drilled under it. A solid concrete wall will not accept a self-tapping screw without first making the seat with a hammer drill. Before you buy a dowel, you need to pay attention to the cap. A Phillips screwdriver or an asterisk (Torx) can be used to position the mount. There may be a nail with a barrel head for a socket wrench or a hexagon (imbus).
For especially heavy things, loaded structures, a metal anchor element is taken, which will be fixed in a spacer type:
- Drive sleeve. The far edge is unclasped by a screwed-in bolt, the near one has a special outer notch that keeps it from turning when installing the mount.
- Wedge. Fixation is provided by a cone, which is pulled up by the screw and expands the spacer sleeve. A similar design is turned not by a bolt, but by a nut along the thread, tightening the wedge to the desired stop.
Pricing
The cost of the anchor is higher than the usual dowel-nail, but its correct operation depends on the sufficient strength of the concrete in which the fasteners are installed.
| Brand, dimensions | Mounting type | Packing, pcs | Price, rub |
| Screw Tech-Krep 7,5 × 52 | Screws into the sleeve | 8 | 90 |
| SORMAT Dowel-nail 6x80 mm countersunk | Screws into the sleeve | 100 | 720 |
| 6x40 mm with a hidden collar | Screws into the sleeve | 200 | 390 |
| 6x40 for mounting frames, racks, GVL | Screws into the sleeve | 1 | 1 |
| StarQuick 6x40 mm | Zabivnoy | 1 | 20 |
| SORMAT LYT LK-SP 8x80mm cylindrical | Zabivnoy | 2 | 44 |
| 6x40mm L with a cylindrical collar | Zabivnoy | 200 | 390 |
| 4.5x30 for PC-84 | Zabivnoy | 1 kg | 110 |
| Facade 10 × 90 with a driven layer. nail KOELNER | Zabivnoy | 250 | 610 |
| BIT-PESF anchor (gas, foam concrete, concrete) | Chemical | 300 ml | 800 |
| Anchor 6x40 | Bolt with nut | 1 | 7 |
| Anchor 6x60 | Bolt with nut | 1 | 8 |
| Anchor 6x75 | Bolt with nut | 1 | 9 |
Materials characterized by a dense structure and high hardness, which include concrete, brick, natural and fake diamond, are actively used not only in the construction industry, but also when performing repair work. That is why the question of which dowels to choose for concrete and other solid materials in order to securely fix various objects on building structures is very relevant.
The fastening element, which will be constantly under load during operation, must be correctly selected not only in size, but also in other parameters. Only in this case will it be able to provide high reliability and durability of the formed connection.
What is a classic dowel
The classic dowel for concrete and other solid materials has been preferred by specialists in the field of construction and repair for a long time. Consumers often refer to it as “nail dowel”. The concrete fastener can be made of metal, nylon and various types of plastic. Naturally, products made from different materials differ in their characteristics and, accordingly, in their field of application.
The bearing capacity of the dowel for concrete is determined by its design features... In the classic version, the dowel-nail is a sleeve, on the entire outer surface of which special notches are made, which prevent such an element from turning in a hole in a wall or in any other building structure. To prevent the fastener from pulling out of the wall, special mustaches help, which, due to their elasticity, are constantly in an open state. When the screw is screwed in, the fastening element is unclenched due to the longitudinal slots on its surface, which ensures high reliability of its fixation.
Parameters of dowel-nails with mushroom-shaped collar used for through installation (click to enlarge)
In addition to the dowel fasteners, which work according to the mechanical principle, on the modern market there are dowels for porous concrete and other similar materials, which are fixed in the holes using a special adhesive composition. Filling the internal cavities of the porous material, the adhesive composition reliably fixes such an anchor element in a previously prepared hole.
The classic dowel-nail, intended for concrete, is such a versatile fastener that it is rather difficult to list all the areas of its application. With its help, they carry out the installation of frames for various purposes, fix furniture and interior items to the surface of the walls, fix household appliances at the required installation site, and also solve a whole list of other important tasks.
What is the difference between a concrete dowel and a brick dowel
High reliability of fastening obtained with the help of dowel-type products will be achieved only if they are correctly selected not only taking into account their size, but also the material of the structure in which they will be mounted.
Experts do not recommend the use of a concrete dowel for installation in brick building structures. This recommendation is especially relevant if it comes about hollow brick. In this case, special fasteners are used for installation, which differ from the usual dowel-nail both in the device and in the features of use.
Fasteners for masonry have elongated dimensions and a double expansion mechanism. Like a dowel designed for concrete work, such a fastener can be plastic or metal. The reliability of fastening the dowel for a brick is ensured due to the fact that at least one of its spacers does not fall into the cavity in the brickwork, but into its solid part, it is he who provides the required fixation of the anchor in the wall or any other building structure. The expansion sleeve of the dowel is unclenched when a threaded rod or screw is screwed into it, the diameter of which must be selected correctly.
The dowel for concrete works in a completely different way and can only be used for installation in solid solid materials. Such a dowel with an interference fit is hammered (therefore it is often called a nail) into a previously prepared hole. If you try to fix fasteners for concrete in a brick wall, in the internal structure of which there are many air cavities, then you can simply destroy the landing hole. Even if such a dowel is metal and has a considerable length, you still will not achieve its reliable fixation in a brick or in any other porous, hollow and not very strong material.
Considering all of the above, one should be very responsible when choosing fasteners for structures made of various materials, differing both in their hardness and in the features of the internal structure. To understand what a particular fastener is intended for, the marking applied by manufacturers to the packaging of such products helps.
Masonry dowel installation rules
Considering the fact that it is somewhat more difficult to install the dowel fasteners designed for bricks than fixing the dowel used for concrete work in the wall, you should understand this procedure in more detail. In this situation, it is very useful to take advantage of the experience of specialists who are often faced with the need to reliably fix objects that have even a very significant weight on brick building structures.
If in order to fix a dowel for work on concrete in a building structure, which is hammered in like a simple nail, it is enough to use a minimum set of tools, then for a neat and reliable fixation of fasteners in a brick wall you will need:
- a hammer drill or drill needed to drill the bore hole;
- drill of the appropriate diameter;
- glue designed for laying ceramic tiles;
- a set of rubber spatulas of different sizes.
The very procedure for installing a dowel into a brick wall consists of the following steps.
- The first thing to do is to carefully drill a bore hole for mounting the fastener. This can be done using an electric drill or a hammer drill, on which the drilling-only mode (no impact) is enabled. It is important that the diameter of the drill used to perform this procedure exactly matches the diameter of the dowel itself.
- After drilling, the hole must be thoroughly cleaned of construction dust and pieces of material that has crumbled into its internal cavity. You can check how thoroughly you cleaned the hole using the dowel itself: it should enter without difficulty and obstacles.
- When the hole is thoroughly cleaned, you can start working with dry tile adhesive, which must be diluted with water in the proportion indicated by the manufacturer. After the glue mass is ready for use, it is necessary to fill the hole drilled for the dowel with it. You can use a rubber spatula for this, and you can push the glue mass into the depth of the hole using the dowel itself or a regular pencil. When the hole is completely filled with glue, you can insert a dowel into it, which should go into it until it stops. After that, it is necessary to allow the adhesive composition to completely solidify, which is quite enough 24 hours.
- After the tile adhesive has completely hardened, you can screw a threaded element (stud or screw) into the dowel. In this case, be sure to pay attention to the fact that screwing in occurs with some effort. This means that your dowel is firmly anchored in the brickwork. Fasteners obtained using such a simple technology are highly reliable and can withstand even significant weight loads.
You can also use this method if you need to install fasteners in a porous material (the use of concrete dowels for such structures is also prohibited). Such materials, in particular, can be gas or foam concrete, porous bricks, etc. Taking into account their high popularity in the modern construction market, the choice of fasteners that could provide reliable fastening of objects fixed to such structures is a rather serious problem.
Concrete anchors are designed for fastening various structures, parts, equipment to the supporting base. A metal product is a rod with extensions, bushings, sleeves or other devices for reliable adhesion to the material. Anchors are made of galvanized or stainless steel of strong grades, brass, aluminum, coated with anticorrosive compounds.
Working principle and application
Concrete is a porous material with a heterogeneous structure. At the point of attachment, forces are created - for pulling out, compression, shear, shearing, bending, twisting, which the anchor perceives together with the supporting structure.
In this case, three principles of work are used:
- When the bolt surface interacts with the base material, frictional forces are generated. The spacer is created by metal collets, dowels.
- At the anchorage depth, the material resists crushing or fracture. This is facilitated by collet bushings on the fasteners, expansion, curved shape of the rod.
The acting loads are compensated for by the shear stresses at the point of contact between the monolith and the metal rod during gluing or embedding. Glue anchors, smooth embedded parts work according to this principle. 
With the wrong selection of fasteners, destruction of the material of construction, the body of the anchor or its tearing, bending, melting, burning out, corrosion are possible. The consequences of this can be catastrophic - collapsing roofs, facades, walls or fences.
Improper design, fastening and operation of anchors in bridges, dams or overpasses leads to emergencies. But even an unexpected fall of a shelf for books, a cornice or a TV is not the most pleasant event, fraught with injuries and material losses.
To prevent this from happening, anchors rely on loads. For the design of fasteners, the Manual to SNiP 2.09.03 is used, which contains a classification, a calculation algorithm, recommendations for the formation and marking of wells, and the installation of bolts.
Anchors perform a load-bearing or structural function. In the first case, this is a loaded mount, where the following is connected to the base:
- beams;
- floor slabs, balcony consoles;
- trusses, columns;
- elevators, flights of stairs and platforms;
- wall or finishing panels;
- communications, engineering equipment;
- window or door frames;
- awnings, canopies;
- outbuildings;
- ceiling lamps, hoods;
- dropped ceilings.
Hardware is used for laying logs on concrete floors or slabs with voids. Installation of anchor bolts is used when attaching hinged furniture and electrical equipment to the wall.
Structural fasteners are used to prevent displacement of parts of the assembly, the stability of which is provided by their own weight, as well as their straightening during construction.
No building is erected without anchors. They are installed before pouring concrete or after - in a prepared hole or a finished well.
Types and methods of fastening
Anchoring is performed different kinds steel products, where one or several acting forces are used at the same time - friction, stop and intermolecular bonding during gluing.
Anchors are classified according to the characteristics:
- purpose - foundation, ceiling, frame, universal;
- shape - straight or curved;
- construction - solid or prefabricated;
- surface - smooth or threaded;
- contact area - for dense or porous material;
- installation method - hammering, screwing in, gluing, through fastening.
Spacers
For the solution of important tasks, expansion anchors for concrete with nuts, where the friction force works, are used. They are a threaded stud with a tapered tip and bushing. When screwed in, it wedges and firmly holds the bolt in the concrete body.
The advantages of these wedge fasteners:
- easy installation of anchors in concrete;
- the possibility of through installation;
- high bearing capacity.
Wedge hardware is used only for dense concrete. They need to be immersed deep enough, they cannot be reused.
If a bracket is installed instead of a nut at the end of the rod, the equipment can be suspended from the bracket.
Varieties of wedge anchor - sleeve or sleeve hardware. They are available as a bolt with a special riving nut at the end or as a stud with a tapered extension. For an even distribution of internal stress, they are reinforced with a double thrust.
These hardware are used in high and medium density concrete. A sufficient contact area with a small diameter of the rod allows it to withstand significant loads.
Hammered
For dense concrete, short drive-in anchors with a metric thread and an internal cone are used. It wedges the base when screwing in a bolt or stud.
The mount is simply made, does not protrude to the surface. This option is used for the installation of ceiling ducts, ducts and other engineering equipment.
Hardware is hammered into the drilled hole, wedged with a punch-hole and a threaded rod of any length is twisted.
The driven ones include a ceiling anchor or a nail dowel, which are attached to the base through the part. This is a convenient connection for Armstrong ceilings, hangers, slats, mounting inserts. Since the bolts are not removable, they are often used as anti-vandal and fireproof fasteners.
Framed
Designed to unfasten window or door frames... The sleeve is cut along the entire length, and a small riving nut, when tightened, pushes the structure against the opening to the desired position.
Stops are located in the upper part of the sleeve to protect against rotation and displacement around the axis.
Self-tapping screws for concrete
A strong connection is created by a thread along the entire length of the hardware. When screwed in concrete, a high shear or pullout resistance of the product occurs. Due to this, the load-bearing capacity of the fastening is very high.
Self-tapping screws take up to 100 kg of load, are easy to install and reliable in operation.
Expanding
These include Molly's bolt, commonly called the "butterfly". Designed for installation of lamps, shelves, cornices, paintings in hollow concrete structures with low bearing capacity.
The collet on a bolt or screw is a drop-down skirt; when the rod is screwed in, it rests against the inner side of the base cavity.
Special spikes on the outside of the collet go deep into the concrete, prevent the hardware from turning or shifting during installation. Butterfly can be sold without a screw.
An anchor of this type is a semi-liquid, fast-hardening mass, with the help of which studs or bolts are glued into the base.
The formulations provide a strong bond with concrete without point or local stresses. The load is evenly distributed along the length of the joint.
Dimensions and characteristics of anchor bolts
Anchor bolts for concrete are classified by size into three groups:
- small - up to 8 mm in diameter and up to 55 mm long;
- medium - up to 12x120 mm;
- large - the maximum size is 24x220 mm.
Mark the anchor according to the dimensions, indicate the thread diameter, drill number, thickness of the attached part, depth of the mounting hole.
For example, the designation of the fastener M8 10 / 60-115 stands for:
- thread diameter - 8 mm;
- drill diameter - 10 mm;
- anchor length - 115 mm;
- thickness of the attached element - 60 mm.
Technical characteristics - minimum pull-out force, permissible bending and maximum torque, weight of hardware - are indicated in the table of fasteners parameters.
Based on the test reports, special tables are drawn up with information about the recommended design and maximum load per unit, the distance from the edge and between the axes. Based on these data, fasteners with optimal characteristics are calculated and selected.
Installation instructions
Anchors for concrete are mounted before the start of pouring the monolith or on a ready-made base. In the first case, a hairpin, bolt or other embedded part is fixed with a wire or welded to the reinforcing cage, then the solution is poured.
To protect the thread from contamination, it is covered with a film. Subsequent work begins after concrete has gained strength.
In the second case, the technology includes well preparation and product installation.
Drilling
Before installing the expansion, driven or expanding anchor bolt in concrete, prepare the hole:
- Mark the positions of the hardware on the base
- With a drill or perforator, drill a hole 20 mm longer than the rod and with a diameter recommended by the bolt marking.
- Use a vacuum cleaner to clean the hole from drilling residues.
If you need to fix any part on the base, first drill it, and then make a hole through the finished hole in the supporting element.
Installation of anchor with nut
The installation of an anchor bolt with a nut is used to secure structures of small thickness, for example, a wooden board or a metal corner, to the base.
The bolt is driven into the hole with a hammer, the nut is tightened with a wrench. It is recommended to use a lath from a bar or trimming a board, so as not to damage the upper part of the threaded hardware.
If the bolt needs to be removed, loosen the nut and remove it from the wall.
For hanging household appliances or equipment on a vertical surface, anchors with a bracket are used instead of a nut. It is screwed in until it stops, making sure that the hook is in the desired position.
Installation of a chemical anchor
Liquid or injection dowels are installed according to the manufacturer's instructions. They are available in capsules or cartridges.
Installation of each type has its own characteristics:
- The capsule is placed in the hole, then a bolt or hairpin is screwed in. Wait until the composition is completely hardened.
- The cartridge is loaded into the pistol, the well is filled under pressure, the hardware is mounted.
Conclusion
In order for the fastening to be reliable, before installing the anchor, you need to calculate the load, select the product according to technical specifications and carry out the installation correctly.
The dowel is a quality element for fixing concrete. It can be applied not only to concrete - it is also designed for stone, brick. Dowels together with anchors are considered the best option for wall mounting household items. The anchoring product differs from the dowel: it is a combined element for fastening, while the dowel is fixed only at the base. Together with self-fastening, the anchor element also has the property of reliably holding the structure, therefore, it is suitable for more massive objects.
Dowel elements are able to hold less heavy structures than anchor ones, but they are great for attaching shelves, cabinets, small wall appliances.
Classic dowels for concrete surfaces
Naturally, the dowel fasteners of various objects on concrete must be of high quality. The classic option is a plastic sleeve with notches along the length and the so-called "whiskers" used to prevent the fasteners from turning through the hole. The main element of such a fastening is a special rod, which contributes to the strength of the fastening in the wall, because when using it, the sleeve expands in the mounting hole. The classic mount is also fairly easy to dismantle. The notches on the rod make it easier to unscrew with a screwdriver.
Application area
Wall shelves are fixed to the wall with dowels. The use of this type of fastener is advisable in various fields. It is that important part that is difficult to find a replacement for. When renovating an apartment, many household appliances and interior items - hoods, wall cabinets, kitchen furniture - must be hung and fixed on the wall. They are held just thanks to the use of dowels - reliable mounting elements.
Distinctive features
A dowel for concrete has many differences from a brick one. It is necessary to familiarize yourself with them, because a responsible attitude to work, analysis of information about dowels will affect the result of installation. It is advisable not to use dowels for hard materials on brick surfaces. For such masonry, there are fasteners with certain features and differences from concrete. The dimensions of the sleeve in this case are lengthened, it consists of a double spacer - to increase the reliability of the fastening, because at least one spacer is guaranteed to hit a hard surface and be fixed on it.
Concrete structures involve a nail as a rod; in brick structures, a hairpin, a self-tapping screw or other components of anchor fasteners are used. The length of the rod is of great importance. A fastener that is too long can cause installation difficulties.
A nail used for concrete structures works differently. The principle involves driving a nail into a hole, and this the simplest way working with concrete, which saves a lot of time. If you use this technique with brick structures or structures made of other loose materials, the surface will simply collapse, and this method will not give the desired effect.
Installation features
If you carefully study the technique, you can make high-quality concrete fasteners at home. Naturally, it is not easy to do this if you do not have the proper experience, but there is a simple and effective method dowel mounting, applied to brick structures. Installers of heavy structures successfully use this method.
For preparation, you will need some tools: a punch, a drill for it, dry glue, a dowel. An electric drill may come in handy.
Dowel-nail installation diagram. First you need to carefully drill a round hole (the size of the drill must be the same as the size of the dowel). After that, you need to thoroughly clean the "hole" where pieces of material and construction dust could remain, get rid of all kinds of obstacles that the dowel entering the hole may collide with. Then apply the glue using either a nail or a long pencil, and after there is enough glue, insert the dowel. It is necessary to wait about a day for the glue to set around the mount.
When the glue dries, you need to do the installation directly. The fasteners must fit snugly against the walls of the hole so that the bolt used for mounting can be tightened with some effort. This guarantees the strength of this type of connection. A similar method of designing fasteners is successfully used in working with other materials. For example, if metal dowels are glued to aerated concrete, they will perfectly hold out on this surface.
Types of dowels
There are a fairly large number of concrete dowels, but the most famous and effective ones should be talked about:
- spacer;
- butterfly;
- universal;
- nail;
- front;
- chemical;
Spacer
The expansion type of the dowel works effectively when installing rigid structures. This type differs from others in the shape and size of the screws. Most often they are in the form of slate, which helps to hammer the dowels into the concrete surface with a hammer.
Sleeves, that is, fasteners of a tubular or cylindrical shape, are also diverse. Some have two spacing, some have three. In most cases, they contain thorns, which are the key to a reliable fixation.
Butterfly
Typically this type is used to work with thin wall coverings. The sleeve is inserted into the hole, and its back side is folded due to the insertion of the screw into the concrete. Thus, the dowel is fixed in the wall.
