Modern industrial and commercial construction is impossible to imagine without the use of prefabricated structures, where the main role is played by sandwich panels. Their effectiveness depends on the quality of the supporting base, which is most often acted by metal-frame. It is the correct geometry and rigidity of metal structures that guarantee the tightness, heat efficiency and durability of the entire building. Errors at the design or assembly stage of the support frame can lead to a violation of the tightness of the joints and the appearance of cold bridges.
Unlike traditional brickwork or monolithic concrete, lightweight enclosure structures require accurate wind and snow load calculations. Metal frame It takes on all the mechanical load, transferring it to the foundation, while the panels perform an exclusively enclosing function. It is important to understand that the rigidity of the system is provided not only by vertical columns, but also by a system of connections, struts and runs that form a single spatial structure.
The choice of material for the frame usually fluctuates between hot steel and thin-walled profiles. For large hangars, warehouses and production shops, it is preferable to use jot-taur and channelers made of steel grade C245 or C345, providing high load-bearing capacity. However, for small commercial pavilions or extensions, it can be used. profiled with a thickened wall, which reduces the overall weight of the structure.
β οΈ Attention: Using a ferrous metal frame without high-quality anti-corrosion treatment will lead to rapid rusting and a decrease in load-bearing capacity. Be sure to require certificates for galvanizing or coating of paint (LCP) class C3 and above.
The construction process begins with checking the geometric parameters of the mounted frame. Permissible deviations in the planeness of columns and runs are strictly regulated by the SNiP and should not exceed 5-10 mm per span. If the frame is skewed, install panels without gaps and stresses will be physically impossible, which will affect the service life of the object.
Types of metal frames and selection of profile for skinning
The basis for fastening sandwich panels are horizontal frame elements called runs, and vertical racks. The choice of section profile depends on the step of the installation and the wind area. The most common double-beam, channelers and Z-shaped profiles. The latter are especially popular due to their ability to minimize heat loss through fastening points.
Z-shaped profiles are made of galvanized steel by cold rolled method. Their unique shape allows you to perform a sweeping installation, creating a continuous bearing line without breaks. This increases the overall rigidity of the structure and allows you to cover large spans without additional racks. Metal thickness For such profiles, it is usually between 2 and 4 mm, which provides a balance between weight and strength.
When choosing the type of frame, the method of attaching the panels is also taken into account. For wall systems, runs are often used, located in increments of 1.5-3 meters. Roofing systems require more frequent stepping or the use of additional suspensions (purins) to prevent panels from sagging under the weight of snow. Load calculation It should be carried out by a professional designer, taking into account regional climatic features.
- ποΈ Double-taver beams - classic solution for heavy industrial buildings with large spans and high ceilings.
- π Z profiles - optimal for reducing the thermal conductivity of the mounting units and ease of installation in complex areas.
- π© Schwellers and corners - are used to strengthen openings, corner zones and create a frame of gate structures.
An important aspect is the fire protection of the metal frame. Steel at high temperatures loses strength, therefore, for objects with increased fire safety requirements is used flame-paint or the cladding of non-combustible materials. The thickness of the flame retardant coating is calculated from the required fire resistance limit of the structure (R15, R30, R45, etc.).
Preparation of the frame and additional elements before installation
Before starting the installation of panels, it is necessary to carefully prepare the places of their adjoining to the metal. The surface of the frame should be cleaned of dirt, oils and welding inflows. Particular attention is paid to the flatness of the profile shelves, since any irregularities will lead to a loose fit of the locking part of the panel.
The key element of the preparation is the installation sealer. These are special tapes of foamed polyethylene or rubber, which are glued to the shelves of runs and racks. Their task is to compensate for the micronervousness of the metal and create an air cushion that prevents the formation of condensation. Without a seal at the points of contact of metal and panel will inevitably occur point-corrosion.
Also at the stage of preparation, lower and upper guides (base and skate elements) are installed. They set the starting point for installation and ensure the correct drainage of water. The installation of these elements must be performed using screw-driver with EPDM washers that ensure tightness.
βοΈ Preparation of the frame for installation
β οΈ Warning: Never use mounting foam to align the frame under the panel. The foam eventually breaks down under the influence of ultraviolet light and moisture, which will lead to loss of tightness and displacement of the lining.
Various additional elements of galvanized steel with polymer coating are used to protect the ends of the panels and places of adjoining to the structures. The navels, corner profiles and frames of window openings are selected in the color of the main covering of the panels. Their installation is carried out after the installation of the main array of walls, but the places of their fastening should be provided in the frame in advance.
Technology of installation of wall panels on metal structures
Installation of wall sandwich panels begins with the bottom row. The panel is raised by a crane in a horizontal position, carefully lowers on the base tide and is fixed. It is important not to damage the protective film and paintwork during the slinging process. For this purpose, vacuum grippers or soft slings are used.
Mounting the panel to the frame is carried out through the outer skin to the metal runs. This is what they use. screw-screw (shooters) diameter of 6.3 mm with a pressing washer and a sealing washer made of EPDM rubber. The length of the screw is selected so that it enters the metal of the frame by at least 5-7 mm, but does not penetrate the inner lining of the panel through.
The mounting step is usually 500 mm (through wave) or according to the project. The screws are twisted strictly perpendicular to the plane of the panel. The twisting of the screw leads to deformation The stains and the stains are in the way of the stains, which will cause the stains to break. After fixing, the panels are connected to each other in a lock connection.
| Parameter | Value/Requirement | Note |
|---|---|---|
| Diameter of the screw | 6.3 mm | Standard for metal attachment |
| Entrance to metal | 5-7 mm | Guarantees reliable fixation |
| Step of attachment | 500 mm | One wave of corrugated |
| Puff moment | Regulated | Without pucking |
Vertical joints of panels (if the wall length is greater than the length of the panel) are performed using the docking profiles Or a slap with mandatory sealing. At joints, additional intermediate runs are often required to ensure the rigidity of the connection. Horizontal seams are also sealed with special compositions resistant to ultraviolet light.
When mounting panels longer than 6 meters, use temporary struts or rods to fix the upper edge before the final mount to avoid displacement under the wind.
Features of laying roof sandwich panels
Roofing panels experience higher loads than wall panels, so the requirements for their installation on a metal frame are stricter. The laying starts with the lower overhang and moves up to the skate. The transverse overlaid of the panels should be at least 200-300 mm, and for small roof slopes - up to 500 mm.
Mounting roof panels is made in the lower wave of corrugated every 500 mm, and in the area of overhangs and skates, the step is reduced to 250 mm to increase wind resistance. For the passage of fasteners through the upper wave (at the adjoining places or for fastening snow retention devices) are used Special thermal washers and sealing mastics.
Particular attention is paid to the device of skates and end. The skating element is installed under the air-element or ventilation tape, providing ΧΨ±ΩΨ¬ moisture from the insulation, but preventing snow and birds from entering the structure. The metal frame in the skate zone should be reinforced by additional bonds.
- βοΈ Snow detention - mandatory element for roofs from sandwich panels, attached directly to the frame through the panel.
- π§ Waterway Organized water drainage prevents wetting of the basement and foundation of the building.
- π¬οΈ Ventilation - a gap between the insulation and the inside of the panel (if necessary) or a ventilated horse.
When installing the roof, you can not walk directly on the panels without special ladders or stairs that distribute the load. The deflection of the external metal sheathing will lead to the destruction of the lock joint and loss of tightness of the roof. All work should be carried out in dry weather at a temperature not lower than -5 Β° C (for some types of sealants).
Sealing of joints and adjoining nodes
The quality of sealing determines the energy efficiency of the entire building. To fill the joints between the panels, as well as places adjacent to the metal frame, are used polyurethane sealants And special sealing tapes. It is important that the sealant retains elasticity at temperature deformations of the metal.
The nodes adjacent to the foundation, the basement and other building structures are closed. balcony And the napkins. Under these elements, a layer of seal is necessarily laid. In the places of passage of engineering communications through walls or roof, passable elements with rubber seals are used, which are also attached to the frame.
Which sealant is better to choose?
For sandwich panels, polyurethane (PU) and silicone sealants are optimally suited. They have high adhesion to the metal, are resistant to UV radiation and do not lose elasticity at temperature drops from -40 to +80 degrees. Acid silicones cannot be used - they cause corrosion of the metal.
β οΈ At negative temperatures, sealants lose adhesion. If installation is carried out in winter, use winter versions of sealants and warm up the place of application with a building hair dryer to +5 ... +10 Β° C.
The inner joints of panels in the corners of buildings and around openings are often closed with decorative pendant. However, the main tightness is ensured by the correct installation of the lock connection and the quality of the seal in the lock. When assembling panels, it is recommended to slightly tap the lock with a rubber kian for a tight close.
Quality control and typical assembly errors
The final stage is the inspection of the installed structure. Verticality of walls, absence of dents, scratches and chips on the coating is checked. Special attention is paid to self-tapping: They should be tightly twisted but not press metal. The puck should be slightly pressed, forming a "skirt" around the propeller's leg.
A common mistake is to ignore the temperature gaps. The metal frame and the panels themselves have different coefficients of temperature expansion. If you do not leave the compensation gaps in the places adjacent to the fixed structures, in the summer the panel can "lead", and they will come out of the locks.
The main criterion for the quality of installation is the tightness of the circuit and the absence of mechanical stresses in the panels. The panel should lie on the frame freely, without curves and distortions.
Also, there is a frequent error of improper storage of panels on the construction site before installation. They should lie on a flat base, in factory packaging, protected from moisture and sun. Long-term storage in the open air without protection leads to color burnout and spoilage polymer.
How to store the sandwich panels before installation?
Panels should be stored in a horizontal position on flat linings (bars) with a step of no more than 1.5-2 meters. The height of the stack should not exceed 2-3 meters. It is necessary to have a canopy or covering material to protect against precipitation and direct sunlight. Moisture must not enter the package.
Can I cut a sandwich panel with a Bulgarian?
The use of angle-grinding machines (Bulgars) with abrasive circles is strictly prohibited, since sparks burn through the polymer coating and zinc layer, triggering rapid corrosion. Cut panels can only be scissors on metal, jigsaw or special disks with hard-alloy solders at low speeds.
Do I need to ground a metal frame?
Yes, the metal frame of the building is part of the lightning protection and must be grounded according to the project. Sandwich panels with metal skins may also require grounding to protect against static electricity, especially in facilities with increased safety requirements.
What is the life of a sandwich panel on a metal frame?
With proper installation and operation, the life of modern sandwich panels is 25-50 years. Metal frame made of galvanized steel lasts 50-80 years or more. Durability directly depends on the integrity of the polymer coating and the quality of anticorrosion protection of the attachment units.