Fungi for fastening heat-insulating boards. How to attach insulation to a wooden wall from the outside. Consumption rate of fungi for attaching insulation.

To make plastic dowels, polypropylene, polyamide, or nylon can be used. The main advantage of polymer dowels is their low price, but the strength characteristics of such products leave much to be desired.

Plastic dowels can be used to attach thermal insulation to strong surfaces made of concrete or brick, but they are not suitable for fixing heavy insulation on hollow walls or surfaces made of foamed concrete.

The average cost of one dowel for thermal insulation with a polymer nail is about two rubles per 1 piece.

1.2 With a metal nail

Metal dowels are an order of magnitude stronger than their polymer counterparts, but their use is limited by the high thermal conductivity of metal, which impairs the overall efficiency of insulation.

Metal dowels form cold bridges - elements whose thermal conductivity is worse than the thermal conductivity of the entire structure.

Also, dowels with a metal nail are prone to corrosion; during operation, they can form yellow rust spots on the plastered facade.

The average cost of a dowel with a metal nail is 3.5-4 rubles.

1.3 With thermal head

Thermal head dowels are a widely used alternative to metal dowels. They are based on the same steel nail, but its head is covered with a material with low thermal conductivity.

As a rule, impact-resistant polyamide is used as a coating, which has a thermal conductivity of 0.027 W/μ, which is comparable to the same characteristic of most popular insulation materials.

The metal nail is completely recessed into a polymer case, as a result of which such a dowel is not afraid of moisture and does not corrode.

The cost of products with a thermal head varies from 4 to 6 rubles per piece, depending on the manufacturer.

1.4 Features of quantity calculation

To ensure reliable fixation of the insulation, it is necessary to use high-quality mushroom dowels, and it is necessary to correctly calculate the required dowels. This can be done using the following formula:

D = T + K + I + Z, in which

T – thickness of the insulation used;
K – thickness of the adhesive used to fix the thermal insulation panels;
I – the length by which the mushroom should go deeper into the wall (no less than 4.5 centimeters);
Z is an optional value used when the wall deviates from the vertical; it is used as necessary.

As a rule, to fasten foam panels with a thickness of 5 centimeters, a mushroom dowel 10.5 centimeters long is used.

The length of the anchor of the dowels, with the help of which the insulation is attached to walls made of brick or concrete of grades M100, M200 and M300, should be 50 mm. If the insulation is fixed to walls made of hollow brick or foam concrete (gas blocks, foam blocks, cinder blocks), it is necessary to use fasteners with 100 mm anchors.

When choosing a mushroom dowel for attaching thermal insulation, consider the advantages and disadvantages of the material from which it is made.

Installation of mushroom type dowels

Mushroom dowel with polyamide nail:

Pros: does not form cold bridges, as it has low thermal conductivity; not afraid of moisture and corrosion;
Disadvantages: it has low strength, which does not allow the use of such dowels for fastening thermal insulation on the facades of multi-story buildings. They have the same disadvantages.

In general, dowels with polyamide nails are well suited for attaching low-density slab insulation to brick or concrete walls.

Products with metal nail:

Pros: high strength;
Disadvantages: afraid of corrosion, worsens the thermal insulation properties of the insulation, as it forms cold bridges.

Using dowels with a metal nail, you can attach insulation of any density - mineral wool, polystyrene foam, polystyrene foam, both to ordinary and hollow walls made of brick or concrete.

Dowel mushroom with polypropylene nail:

Pros: low cost, low thermal conductivity, which eliminates the formation of cold bridges; does not corrode;
Cons: durability.

The scope of operation of this dowel is similar to mushrooms with a polyamide nail.

Products with thermal head:

Pros: high strength, not afraid of corrosion, does not form cold bridges;
Cons: the price is the same

Dowels with a metal nail, the head of which is covered with heat-insulating polypropylene, are a universal option with which you can attach any insulation to any surface.

2 Features of installation of thermal insulation

The technology for installing any slab insulation - expanded polystyrene, polystyrene foam, or penoplex - with mushroom-type dowels is identical. All insulation work essentially boils down to the following algorithm:

Preparation of the insulated surface;
Installation of panel thermal insulation on an adhesive solution;
Fixing panels with dowels;
Treatment of insulation joints;
Installation of insulating film;
Covering thermal insulation with decorative material or plastering.

Before installing the insulation, it is necessary to prepare the surface - remove the plaster, repair cracks and irregularities, and degrease.

Next, panels of expanded polystyrene, polystyrene foam, or penoplex are mounted on a special adhesive composition that does not contain organic solvents - toluene and acetone. During installation, the adhesive mixture must be evenly distributed over the entire back surface of the insulation.

To avoid shifts in the thermal insulation under its own weight, a metal profile is installed under the first row of slabs, which takes on the function of support.

After the day required for the solution to dry, fungi are used to further fix the thermal insulation.

To drill holes, drills are used, the diameter of which is equal to the diameter of the leg, and the length of the hole should be one centimeter longer than the length of the dowel, so that dust collected in the hole does not interfere with reliable fixation.

Building codes define the following standards for the number of dowels used:

To attach thermal insulation to internal walls or to the facades of one-story buildings, five pieces are required for each square meter of insulation - 4 in the corners, and one in the center of the panel;
For fastening on the corners of buildings - 6 pieces each (fungi are installed parallel to each other);
For fastenings on the facades of buildings with a height of 8 to 20 m, 7 pieces per 1 m² of insulation are required (parallel + 1 in the center);
For fastening on the facades of multi-storey buildings with a height of over 20 meters - 9 pieces per square meter of thermal insulation.

It is best to place fungi at the joints of foam or penoplex panels, since this method does not lead to a significant increase in holes in the thermal insulation, which negatively affects its effectiveness.

If the mushroom dowel needs to be installed in a metal covering made of corrugated sheets, a self-tapping screw is attached to the dowel leg, after which the thermal insulation is pressed through so that the self-tapping screw reaches the insulated surface.

After this, using a screwdriver, the dowel with a self-tapping screw tip is screwed into the metal. The depth of the hole for the screw should be at least 10-15 millimeters.

Upon completion of the installation of thermal insulation, the joints between the foam plastic or penoplex panels are glued with aluminum reinforcing tape. The joints between the floor or ceiling and the adjacent panels are sealed with polyurethane foam.

Sometimes they do it additionally.

2.1 Installation technology (video)

Installation of insulation

Selecting reliable fasteners for installing insulation is a strategically important task. These tiny details can either permanently eliminate the problem of cold in the house, ensuring a reliable fit of the insulation to the surface of the facade, or lead to very sad consequences. After all, unsuitable fasteners will not securely fix the material, and then winter will not only be outside the window - it will settle in your house. Let's talk about what you need to know about dowels for attaching insulation.

Dowels: mushrooms and plates

For fastening hard and soft insulation, the so-called mushroom dowels for thermal insulation, or, to put it differently, plate-shaped mushrooms. They are able to hold even loose and fragile insulation. Using a mushroom dowel, you can mount the material on almost all types of flat surfaces made of concrete, brick, foam concrete and aerated concrete, as well as building stone.

Disc-shaped dowels hardware have become widespread due to the unique design of the outer cap - it is quite wide in size and has conical holes that allow the mineral insulation to be securely fixed. Good load-bearing performance is ensured by a long wedging zone. The disk of such a dowel has a rough surface and special technological holes. They ensure reliable pressing of the material to the base. In addition, the fixation of the insulation is facilitated by a spacer zone (60 mm), consisting of three sections, which, among other things, completely prevents the dowel from being pulled out of the hole.

The main component in the manufacture of dowels is low-density polyethylene (HDPE), and the expansion nail is usually made of galvanized steel or glass-filled polyamide. Hardware not only helps preserve heat, but also has excellent anti-corrosion properties. The disc-shaped dowel is firmly fixed in place by spreading it with a nail, screw or screw. Moreover, it expands in two or three directions, which makes it possible to effectively fix all known types of insulating materials, as well as increase the fastening strength and load-bearing capacity of the dowel itself. In addition, the plastic material of the product avoids the formation of cold bridges and is characterized by resistance to aging, which, together with other quality characteristics, guarantees high reliability of the fasteners for many years.

The disc dowel, in particular its head, is highly flexible, due to which compensation occurs for thermal expansion and deformation of the material. This, in turn, makes it possible to reduce damage to the insulating layer itself to zero.

A variety of dowel shapes for insulation

The disc dowel consists of a core and a wide cap, which allows you to reliably fix any heat-insulating material on the facade of a building using galvanized metal nails. The disc dowel made of polyethylene is resistant to corrosion and, unlike outdated wooden plugs, does not collapse, does not rot, and reliably and firmly fixes the thermal insulation on the facade.

There were also threaded dowel nails, due to which they can simply be driven into the surface. They are made from glass-filled polyamide or galvanized metal. As a rule, the most common materials for making mushroom dowels are metal and plastic.

Metal dowel for insulation It is more expensive, but at the same time it can withstand much greater loads compared to plastic. Metal mushrooms are used for fastening to hollow and thin-walled structures. Thanks to the zinc coating, such fasteners do not corrode, which improves the durability and reliability of the entire thermal insulation system of the house.

Plastic dowels There are two types on sale: nylon and polypropylene. Nylon dowels are designed for installation to solid, hollow materials and wood, that is, to virtually any base. They are supplied complete with a metal screw (diameter - from 2 to 16 mm), the dowels can withstand a maximum load of 225 - 450 kg for concrete and 160 - 380 kg for brick. As for the polypropylene dowel, it is capable of taking a load from 20 to 750 kg.

Installation of insulation

The principle of operation of fastening dowels for insulation

Despite the fact that there are different technological processes and materials are constantly being improved, the physical law by which the dowel secures thermal insulation remains unchanged - this is the holding force of friction. In this process, it is so large that the fastener can only be used once - when removed from the hole, it will simply collapse. Another way to damage the fastening is to pull it out under the pressure of the insulation. Such troubles can be avoided if you carefully prepare the seat.

The hole for installing the disc dowel must correspond to the required diameter and depth of the fastener. The presence of cracks, chips, sand or dust residues inside it is unacceptable. Thanks to their shapes and the presence of various spacer zones, fasteners for thermal insulation are securely fixed on almost all types of surfaces. At the same time, external factors practically do not affect the strength of such fastening during the subsequent operation of thermal insulation systems.

Dowels for monolithic foundations have a spacer principle of fastening, and for hollow cores they have an anchor principle.

Traditionally, the required dowel length for insulation is calculated using the following formula: L = H + K + I + W, where:

L - required dowel length;
H - thickness of the insulation layer, obtained on the basis of thermal engineering calculations;
K - thickness of the adhesive composition for gluing the insulation;
I is the length of the spacer part of the dowel (it must be at least 45 mm);
W is the sum of actually determined deviations of the building’s base from the vertical and the deviation of the façade plane in the places where dowels for thermal insulation are installed (a kind of safety margin along the length of the fastener).

When installing a heat-insulating layer consisting of materials with high deformability (semi-rigid mineral wool boards), it is best to choose dowels with an expansion washer with a diameter of 100 mm

The process of attaching insulation with dowels

Direct installation of insulation dowels is simple and consists of only a few operations.

Marking the locations of proposed installation.
Drilling holes for fasteners through a layer of thermal insulation.
Installing the dowel: it is pressed into the hole until the head is pressed tightly against the insulating material.
Installing a nail for expansion and hammering it until final fixation.
Attaching the nail head protective cover.

When attaching the insulation, be sure to remove the old plaster (if any) or increase the drilling depth. Fastening dowels involves inserting the anchor element into the load-bearing layer of the wall exactly the entire length. When reducing the length of the spacer element yourself (which happens quite often), it is imperative to sharpen the cut end. To install the dowel, make a hole with a diameter of 10 mm (± 0.3 - 5 mm). Its depth in the load-bearing wall should be 55 - 60 mm for an anchor element measuring 50 mm, 105 - 110 mm for an anchor element measuring 100 mm.

After this, a dowel is placed in the hole, and the disc-shaped and anchor elements are first placed on a fiberglass rod. Using a hammer, the protruding part of the rod is hammered to the level of the flange. At the same time, tension is created in the anchor element, which ensures reliable adhesion in the “wall - anchor element - rod” system. For standard fastening, use five to six dowels per square meter. m walls. The exact amount of fasteners required is determined by calculation based on the area of the insulated surface.

Dowel for attaching insulation

Currently, the market offers a huge range of different types dowels for insulation, designed for various thermal insulation materials, taking into account their thickness, weight and other characteristics. The main producing countries of such hardware are Russia, Germany, China and Poland. The price range ranges from 3 to 30 rubles. per piece (the cost depends on the materials from which the dowel is made, as well as on the manufacturer’s brand).

When performing thermal insulation of walls, one of the main tasks is reliable fastening of insulation. In addition to the adhesive solution, if one is used, thermal materials are fixed with special hardware.

A disc-shaped dowel, also known as a mushroom dowel, or an umbrella, or a fungus, provides reliable fastening of all types of insulation to any wall structures. The quality of the work performed and the durability of the structure depend on the correct choice of a specific type of dowel. There are various types of these products on sale, designed for every, even the most intricate combination of building materials.

The dowel head is a wide disk 60-100 mm in diameter with technological holes. To ensure adhesion to materials, the disc has a rough surface. Further from the head is the body of the dowel, which ends in a spacer zone, which, in turn, consists of several sections, which sets different vectors of forces during expansion.

The dowel is equipped with a core nail, which, when driven in with a hammer, creates a force in the expansion zone. This design ensures reliable fixation of the “fungus” to the wall under the influence of the weight of thermal insulation materials.

Materials for production

Facade dowels are produced in such a way that they are not susceptible to atmospheric influences, mechanical and chemical loads. Design operating temperature from −40°С to +80°С. In order to meet the stated requirements, the following materials are used for the manufacture of fasteners:

Nylon or low-density polyethylene (HDPE). It is used for fixing insulation to any type of wall: concrete, brick, hollow, wooden. A metal screw is used as the core. They can withstand loads of up to 450 kg on a concrete wall and 380 kg on a brick wall.
Glass-filled polyamide. It is also used for all types of walls with a galvanized metal core, as well as with polyamide, fiberglass reinforced. Withstands loads up to 750 kg.
Galvanized iron. This type of dowel for thermal insulation is used when attaching insulation to thin, hollow walls. Resistant to rust, the principle of operation, unlike wedging, is anchoring. The strength of the wall determines the load-bearing load of the dowel. It differs from previous samples in its high cost.

The metal core is used when installing materials with a high specific gravity in order to increase the load-bearing load on the dowel. However, a significant drawback of this design is cold bridges that arise due to the high thermal conductivity of the metal. To eliminate this phenomenon, a dowel for thermal insulation with a thermal head is used.

Calculation of the length of the disc dowel

Before purchasing fasteners, you need to calculate their length. It is determined by the formula:

L = H + K + W + I, where

L - required dowel length

H - thickness of the selected insulation

W - actual deviation of the wall surface from the vertical

I is the length of the spacer section of the dowel.

The required number of fasteners is determined at the rate of 5-6 pieces per square meter.

Rules for installing fungi

The disc dowel is designed for final fixation of the heat insulator, so installation is carried out after the insulation is already on the wall. Polystyrene foam, extruded polystyrene foam and mineral wool slabs are initially attached to the wall surface with a special cement-based adhesive, while mineral wool rolls are placed in frames. And after that they are fixed with disc-shaped dowels. Ideally, installation of insulation and dowels is best carried out at an ambient temperature of 0°C, approximately in the middle of the operating range.

Installation is carried out in the following sequence:

Installation locations are marked
In the designated places, holes are drilled with a hammer drill directly through the insulation. The diameter of the drill must match the diameter of the dowel. The depth of the hole should be equal to the length of the dowel plus 10-15 mm.
Next, the dowel is inserted into the hole until the cap of the fungus comes into contact with the insulation and is pressed tightly; finishing with a hammer is not required.
The core is inserted into the dowel and hammered in until the fungus is finally fixed in the wall.

You need to purchase disc dowels from trusted retail outlets with a solid reputation and only under the trademarks of well-known manufacturers. In small businesses, it is popular to produce such products using injection molding machines in garages from recycled materials, and the quality of the products does not always meet the standard. Such dowels not only may not be able to cope with the load during operation, but even at the installation stage they crack and crumble. It will not be possible to pull out an under-filled dowel due to its design - the barrel is equipped with tendrils, you will have to cut it off, spoil the insulation and drill a new hole for a new dowel.

The fungus for attaching the insulation is one of the most important parts of the thermal insulation layer. Thanks to these fungi, you can get rid of the cold in the room once and for all, achieve the tightest possible fit of the insulating material to the walls, or form new “cold bridges.” In this article we will tell you what this element is, what it can be, what its cost is, etc.

Prices

The cost of disc dowels (if we talk about Moscow and the Moscow region) is at least 1.5 rubles per unit.

You can save a little money by ordering in bulk. There is another way to reduce the final cost - for example, pickup.

Table. Average market prices for umbrellas

The main advantages of the disc mount

When installing any thermal insulation material, special dowels are used - they are called heat insulator mushrooms or umbrellas. Such products are capable of reliably fixing even material that is characterized by fragility or low density.

Using such fungi, you can attach a heat insulator to concrete, stone, brick and other materials.

As a rule, the fungi are made from low-pressure PE (or HDPE for short), while the wedge can be made from polyamide or galvanized. The main advantages of the described element are given below.

Umbrellas owe their widespread use to their special design: their outer cap is wide enough, thanks to which any insulation (up to mineral wool) is securely fixed.
Having a long leg, the umbrella is able to withstand very significant load-bearing loads. Moreover, the fastening is enhanced by the long spacer zone, which therefore consists of 3 sections. The cap itself is somewhat rough, and there are also special holes on it.
Dowels for heat insulation not only contribute to heat conservation, but also have increased anti-corrosion qualities. And if you compare them with the already outdated corks made of wood, then polyethylene umbrellas do not rot or destroy.
Plastic is a reliable and durable, but at the same time cheap material.
The umbrellas themselves are flexible enough to level out the narrowing/expansion of the surface in order to avoid damage to the insulation.
To make the connection as reliable as possible, the fungus inserted into a special hole using a wedge must be opened. What is characteristic is that the expansion occurs in all directions at once, due to which the adhesion to the working surface only increases.

Previously, we talked about how to calculate the required thickness of insulation at home; in addition to this article, we advise you to read this information

The main types of mortars for insulation

Any disc dowel consists of a sleeve, a core and a wide cap. Below are the main types of fungi.

Video - Types of fungi for fixing a heat insulator

It is also worth adding that there are still dowels with threaded threads that can simply be driven into the work surface. They are produced in two versions:

made of metal (we are talking exclusively about the core);
made of plastic.

The cost of iron mushrooms is approximately twice as high, but they can also withstand much more weight. Field of application: fixation to thin or hollow materials. Plastic dowels, in turn, are divided into:

PP (polypropylene);
nylon (used for surfaces made of any material).

It is also worth highlighting roofing fungi. They are intended for installation of soft roofing, acoustic slabs or thermal insulation to a concrete surface. Such products consist of a 5-centimeter cap, a fiberglass rod or self-tapping screw and an anchor.

Note! An element made entirely of plastic is preferable to use for thermal insulation of walls. This is explained quite simply: iron conducts cold well, therefore, the notorious “cold bridges” will form along the entire length of the metal rods.

Operating principle

Despite the fact that technical progress is advancing by leaps and bounds, and building materials are constantly being improved, the dowel described here (or a fungus for attaching insulation) is attached in the same way as before - it holds due to the fact that the holding force of friction acts on it. It is worth noting that this force is so significant that it is not for nothing that this fastening method is called disposable: if you remove the umbrella from the hole, it will simply collapse.

Of course, there is another way to hopelessly damage an element - you just need to tear it out along with the insulating material. To avoid all this, it is imperative to ensure that the seating area is arranged correctly. It is important that the hole for the umbrella fully corresponds to the required depth and diameter. Chips and cracks in the holes are unacceptable, as is the presence of installation dust in them.

Insulation with foil

Previously, we talked about the advantages of insulating material with foil, its technical characteristics and cost; in addition to this article, we advise you to read this information

How to correctly calculate the length of the fungus for insulation

In most cases, to determine the required length, approximately the following formula is used:

A + B + C + D = E.

Let's look at the symbols. They look like this:

E- this, of course, is the required length of the dowel;
A– the thickness of the insulation material itself;
IN– this includes the thickness of the previous plaster, as well as glue;
WITH– depth of penetration into the working surface (wall), which must be at least 45 millimeters;
D– approximate margin, which is necessary for minor deviations of the working surface plane.

Although if you do everything “by eye”, the procedure will look even simpler: 40-45 millimeters are added to the thickness of the thermal insulation material for the recess, then another 10 millimeters for the remaining layers of the pie. For example, the thickness of the insulator is on average 50 millimeters, which means - if you make simple calculations - it will require a fungus 105 millimeters or 10.5 centimeters long.

Note! If the walls are made of brick or concrete above the “fiftieth” grade, then an anchor element 0.5 centimeters long is sufficient. But if we are talking about loose concrete, hollow bricks or load-bearing walls, as well as other loose materials, then it is necessary that the anchorage length be approximately 10 centimeters.

Installation of insulation using special mushrooms

Now let’s figure out how the insulation procedure generally occurs using such fastening elements. Let’s say right away that there is nothing complicated about this, so you can easily do the job yourself. Below are the main steps of this procedure.

Stage one. First you need to prepare the base.

Stage three. Then the fastening is carried out, for which the already known disc-shaped dowels are used (this is also called a fungus for attaching insulation).

Stage four. All joints are carefully sealed.

Stage five. A hydro- and vapor barrier layer is installed.

Stage six. The surface is plastered using a fiberglass reinforcing mesh (if necessary, of course).

Stage seven. At the end the final finishing is done.

Let us consider in more detail the technical aspects of the insulation procedure.

First you need to prepare the surface. To do this, the previous plaster is cleaned off, all depressions and bulges are eliminated to create a smooth surface. Then the insulation is attached to the working surface using a special adhesive mixture. If the surface is fairly smooth, you can use a notched trowel for application; although in most cases the mixture is simply thrown onto the slabs in small piles.

So that the first row does not fall under the weight of the subsequent ones, a so-called starting bar is attached to the lower part (you can make it from a metal profile or lath), where the sheets will rest. Then, when the glue is completely dry (usually this takes two to three days), the sheets are finally secured with the described fungi. First, holes are made in appropriate places using a hammer drill. It is important that the drill used is the same thickness as the stem of the fungus.

The depth of each hole should be about 0.5-0.7 centimeters so that the fungus is completely clogged there, regardless of whether there is installation dust there. The number of dowels for one insulation board depends on the height of the ceilings and their (slabs) location.

If we are talking about an ordinary area, then it should be fixed at the rate of five fungi for every square meter.
In the case of corner plots, this number can be increased to six.
If the height of the room varies between 8-20 m, then the number of umbrellas will already be seven per square.
Finally, if the ceiling height exceeds 20 m, then one square of insulation is attached in 9 places.

It is advisable that the fastening points be located at the joints of the sheets - this way you will be able to avoid the formation of additional holes “for ventilation”; moreover, after installation, the edges of the plates will not be bent. In the image below you can see what several common fastening methods look like.

Note! If the insulation sheets should be attached to a surface made of metal or to corrugated sheets, then first insert a self-tapping screw into the dish-shaped part, and then screw it all on using a screwdriver.

Next, the insulation is pressed with a fungus to the very base. The screw is screwed into the metal so that the cap fits as tightly as possible to the thermal insulation material. It is important that the self-tapping screw goes at least 1.5 centimeters into the base.

More detailed instructions are shown in the image below.

Then all joints are carefully sealed using thermo-retractable metallized tape. If there are gaps of more than 0.5 centimeters remaining, they can be blown out using polyurethane foam. Although this should be done with extreme care, since some types of foam can corrode the polymer heat insulator.

If you plan to build a ventilated facade, then the mineral wool must be covered on top with a special membrane for hydro- and vapor barrier. Although there are exceptions - insulation materials that do not absorb moisture well (foam, for example, or polyurethane foam).

During plastering, the surface is covered with a 3 mm layer of adhesive, which will serve as protection. The composition should be applied evenly, so it is preferable to use a notched trowel for this. Next, a mesh reinforcement made of fiberglass is pressed into this layer, while maintaining an overlap of ten centimeters. To finally level the working surface for finishing, the walls should be treated with another layer of mortar and leveled using a long rule. The video below demonstrates how thermal insulation material is installed if a fungus is used to attach the insulation.

Video - Installation of insulation using umbrellas, 4 cm3>

Video - Thermofix Fischer thermal insulation dowel

As a small conclusion

If you are planning to insulate your home, then be sure to adhere to the technology, which means it is strictly not recommended to save on fasteners. Otherwise, they will not be able to withstand the mass of plaster and will collapse along with the entire thermal insulation “pie”. This especially applies to corner areas, because they are known to be loaded the most during strong wind gusts.

The microclimate in the interior of a house cannot be comfortable without high-quality insulation. Developers of thermal insulation materials are constantly introducing various systems into production that make it possible to protect the room from the penetration of cold. To attach their components, special devices are required, the basis of which is dowels for thermal insulation.

Purpose

The invention of the dowel solved the important problem of increasing the strength of the connection of screws and nails with various surfaces. Its varieties began to be actively used in construction, in particular when insulating houses both outside and inside.

The disc-shaped dowel is considered multifunctional (it is also called a mushroom). The large diameter of its disk with conical holes is capable of perfectly holding both mineral and polystyrene foam insulation, and the elongated spacer rod secures the entire structure as firmly as possible.

The plate-shaped mushroom is firmly fixed in the right place by spreading it with a nail in three directions.

Based on the specifics, the features of dowels for thermal insulation make it possible to fasten with their help various materials on bases made of brick, all types of concrete, stone, wood, gas and foam concrete. This element has become indispensable in the installation of various types of thermal insulation materials, as well as in the construction of plaster, aluminum frame and ventilated facades.

Types of disc dowels

Types of mushroom dowels

Such products are made from plastic, various metals and their alloys in various types and sizes. Considering the method of application, they have diverse characteristics and are designed for high-quality interaction with all insulation materials, regardless of the material and method of production. For fastening thermal insulation, two main types of mushroom dowels are used:

Plastic with a plastic nail.
Plastic with a metal nail.

Depending on the type, fasteners for thermal insulation differ in their purpose.

Plastic dowels with plastic nail

Typically made from polypropylene or nylon. They have excellent characteristics:

strength;
ease;
eliminate cold bridges;
do not rot;
do not collapse, unlike wooden plugs.

Important. Dish-shaped mushrooms made of polypropylene and nylon are best used for attaching foam plastic, penoplex (extruded polystyrene foam) and mineral wool in the form of slabs to concrete, brick and any hollow bases (such as hollow bricks).

Length of plastic fasteners – 70 mm – 395 mm;
Diameter of the large base (disk), standard – 60 mm;
The diameter of the rod is 8-10 mm.

The thickness of the thermal insulation material for fastening varies from 30 to 170 mm.

A dowel for thermal insulation made of plastic has a nail, which is made from nylon with the addition of fiberglass. It is lightweight, impact-resistant and can support loads of up to 350 kg.

Plastic dowels with metal nail

Such mushrooms can be used for fastening insulation from cork slabs and mineral wool on all bases - concrete, brick, cellular concrete, wood.

The nails for such dowels are made of galvanized metal. Compared to plastic ones, they can withstand higher loads:

for concrete 225 – 450 kg;
for bricks 160 – 380 kg.

Such rods are suitable for fastening heavy insulation and moisture-accumulating materials.

Drive element length – 90 – 260 mm;
Disc diameter – 60 mm;
Hole diameter – 10 mm;
The thickness of the insulation for fastening is 30 – 210 mm.

Both types of fastening systems can be effectively operated at temperatures from -300°C to + 800°C.

To eliminate cold bridges that negatively affect the integrity of the thermal insulation (in the case of metal nails), fasteners with a thermal head were created. They are plastic attachments attached to the driven end of a nail.

Calculation of the length of dowels and their number

To securely fasten the insulation, you need to correctly calculate the length of the mushroom rod. When calculating, we use the formula: L (rod length) = E + H + R +V. Let's decipher the meaning of the terms:

E – length of the spacer section of the dowel rod;
H – thickness of insulating material;
R – thickness of the adhesive layer (if there is a need for gluing);
V – deviation of the structure from the vertical plane.

Important . The length of the spacer section of the plate mushroom (dowel) must be at least 45 mm.

The consumption of the number of dowels for installing insulation directly depends on its weight. For example, penoplex can be fixed with 4 mushrooms per 1 m2, and basalt wool will require at least 6 pieces of plate mushrooms. The exact amount is found by calculating the surface area to be insulated.

The formula for finding the total fastener consumption looks like this:

W = S * Q, where:

S – total surface area;
Q – number of dowels per 1 m2 of insulation.

To the result obtained, you need to add 6-8 pieces in case of unforeseen circumstances (loss or breakdown). When calculating consumption, keep in mind that, unlike walls, more fasteners are needed for corners. Therefore, we add another 12-15 pieces.

Installation

The installation of thermal insulation using disc dowels is a very simple process. It consists of a list of the following works:

Marking the area for installation.
Drilling holes at right angles for fastening together with thermal insulation.
Installation until the disc fungus is completely adjacent to the insulation.
Driving a nail for expansion and final fastening.
Attaching a nail-protecting cap.

Before fixing the thermal insulation, you need to either remove the old layer of plaster or increase the drilling depth. For ease of use, the heat-insulating material is first glued to the walls with a special adhesive, allowed to dry, and only then the dowels are installed.

The hole for fastening is made 8 - 10 mm wide. The depth should be 60 mm for a 50 mm anchor component, and 110 mm for this 100 mm component.

After attaching the thermal insulation material, there remain fairly deep holes that need to be sealed using a paint spatula. To do this, you can use the same solution as for gluing the insulation.

Advice. If you decide to reduce the length of the spacer, be sure to sharpen the truncated end.

Today, the dowel for thermal insulation is the main fastening system offered on the building materials market. The leading manufacturers in this area are Russian, Polish and German enterprises. To ensure high-quality insulation of your home, it is better to purchase products from these countries.

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