Slope angle of a sandwich panel roof. Minimum roof slope made from sandwich panels

During the construction of residential and industrial buildings Sandwich panels are often used. This is an inexpensive building material, from which walls and roofs are mainly built.

Structure

Sandwich panel is a sheet consisting of the following layers:

• external covering on both sides (galvanized steel, polyester, oriented strand board or plasterboard);
• insulation (mineral wool, polyurethane foam, fiberglass or polystyrene foam).

Advantages of sandwich panels

The widespread use of this building material for roofing is explained by the following advantages:

• thermal insulation at a high level;
• low level of flammability;
• low cost;
• high level of sound insulation;
• no need for complex construction equipment for styling;
• reduced load on bearing structures due to low weight;
• a wide range of shades, so there is no need for additional finishing;
• high resistance to negative environmental influences (humidity, microorganisms, chemicals, temperature changes).

Construction of the roof

In order for a roof made of sandwich panels to be reliable and of high quality, the following rules must be taken into account:

• Minimum possible angle roof slope - 50. This is the lowest level, exceeding here is permissible.
• Only solid panels without joints, windows or other elements that would interfere with their integrity are suitable for installation.

Since 50 is the minimum mark, other criteria are needed to determine the angle that is suitable for this particular roof. An important one is the climate of the region in which the building is being erected. If the region is characterized by frequent and heavy rainfall, then it is necessary to provide a slope that would maximize the removal of moisture from the roof. The optimal indicator here is 400. This way, water will not stagnate at the joints, and in winter this is especially important, since snowdrifts and ice destroy the roof, widen the cracks and lead to the risk of collapse if snow masses have accumulated in large quantities.

If the climate is quite arid, then the slope is allowed from 70 to 250.

You should remember this ratio: the steeper the roof is erected, the greater the consumption building materials will be needed. If the roof is quite flat (5-7 degrees) there is no need for additional fasteners to secure the sandwich panels to a supporting structure made of metal, reinforced concrete or wood. However, if this low level is exceeded, additional connecting fasteners are indispensable.

Formulas for calculation

Slope is the angle of inclination of the roof surface relative to the horizon. The greater the angle, the greater the steepness of the roof. The slope is expressed either as a percentage or in degrees. For example, 40 is equivalent to 7%.

Necessary equipment

When constructing a roof from sandwich panels, it is necessary to constantly trim them using electric shears, a stationary machine or a fine-toothed saw. A grinder or hot cutting devices are not recommended here, since when heated, the cut lines are deformed and bent, the protective coating is broken and corrosion appears.

To transport the panels to the roof, vacuum or mechanical grips are used, which do not damage the surface or compromise the integrity of the slabs. Before installing the grips, a protective film is glued in the required places. The panels are secured using long stainless steel self-tapping screws for sandwich panels, supplemented with sealing gaskets and washers. The length of the fasteners must correspond to the thickness of the slabs and frame.

To prepare for work, you need to first calculate how many fasteners you will need. Their number is influenced by the following factors:

• Wind load. This factor depends on the height of the building, its location and the angle of the roof.
• Type of construction (closed or open).
• Fastening area. The outer panels experience more wind load than the slabs located in the center.
• Characteristics of fasteners (load-bearing capacity).

Based on all these factors, the required number of hardware is calculated, and it is important that the resulting figure corresponds to the proper SNiP.

Secrets of proper styling

When constructing a roof from sandwich panels, it is important to maintain their integrity, otherwise the result of the work will be unsatisfactory. The following recommendations will help you complete the entire process correctly:

• When cutting slabs, abrasive or hot cutting is not allowed, as it damages the integrity of the protective layer.
• Sandwich panels are covered with protective films on both sides. It must be removed from the lower part immediately before the installation is carried out, not earlier. The top film must be removed upon completion of all work so as not to stain or deform the surface.
• If shavings appear during the cutting process of metal, they must be removed immediately so that they do not linger on the surface of the slab.
• When performing installation work, workers on the roof must wear shoes with soft soles only.
• If the slabs are stored under open air, you need to take care of their protection from aggressive weather influences. It is recommended to stack the material on a flat and dry area.
• The weather for installation should be dry, without precipitation or strong wind. The maximum permissible wind speed is 9 m/s. The minimum ambient temperature is +40C.
• Necessary good lighting for the installation process.

Preliminary inspection

Before laying a sandwich panel on the roof, you need to carefully inspect the roof structure so that it fully complies with the project; the correct installation of the slabs depends on this. If defects and errors are found, they must be eliminated before installing the sandwich panels.

Laying process

Sandwich panels are mounted transversely to purlins located parallel to the eaves. To improve the load-bearing capacity of the roof, you can reduce the installation step of the purlins. This is relevant when constructing a roof with a slight slope, if the region is characterized by heavy snowfalls.

Before erecting the slabs, a layer of waterproofing and insulation is laid (mineral wool is often used for this purpose). The purlins and supports are checked. All deposits, including mold and rust, must be removed. Preliminary preparation supports depends on what material they are made of.

• Wooden structures are cleaned of mold and mildew, and cracks on their surface are repaired. Apply protective layer, preventing fire and mold.
• Metal elements are coated with an anti-corrosion agent.

First, slabs are laid, the length of which does not reach 10 meters. Thanks to their low weight, they can easily be lifted onto the roof. It is forbidden to lock the panels, as this may cause the panels to bend. Laying begins from the bottom corner of the roof and is carried out vertically: from bottom to top.

Conclusion

The roof slope is one of the factors that determines the installation process and further operation. To avoid corrosion, leaks and other troubles, it is important to correctly calculate what slope the roof should have.

This parameter is influenced by the climatic features of the region where the building is being erected.

Roofing from sandwich panels is a new word in the arrangement of pitched and flat roofs of various configurations and sizes. Design features materials allow you to create a sealed coating with ideal qualities. Sandwich technology involves the installation of ready-made roofing components. The construction of roofs using the roofing “pie” technology will require up to 50% less time than for laying other materials. The technical parameters of the building material, features of its installation and operation are discussed further in the review.

What are sandwich panels

Sandwich panel is a building material with a three-layer structure. The components of the roofing panel are tightly bonded to each other using a two-component polyurethane-based adhesive. The upper and lower layers of the three-level system are made of thin-sheet galvanized steel with a polymer coating. Thickness metal elements"pie" is 0.5 or 0.7 mm. Steel sheets are profiled with stiffening ribs. The middle layer is represented by insulation, which is a basalt mineral wool, polystyrene foam or polyurethane foam board.

Advantages of roofing material:

• presentable appearance;
• durability;
• increased fire resistance;
• strength;
• resistance to deformation;
• light weight;
• ease of installation work;
• resistance to aggressive environments and others negative impacts from outside.

Characteristics and dimensions

A roof made of sandwich panels is characterized by good sound insulation, excellent thermal insulation qualities and water resistance. Sandwich roofing does not allow cold air to pass through from the outside and traps warm air inside the premises.

The linear parameters of a standard slab are:

• width – 1000 mm;
• length – from 2500 to 16000 mm;
• product thickness – from 50 to 250 mm.

The main characteristics of roofing material are thermal conductivity, load-bearing capacity, fire resistance, sound insulation and weight. The key influence on the technical parameters of the product is the type of insulation and the thickness of the panel.

The guideline for choosing panel thickness is the thermal insulation indicator. The thicker the slab, the more thermal air will be retained in the middle of the building.

Indicators of sandwich panels with insulation from mineral wool:

• sound insulation – from 30 to 43 dB;
• thermal conductivity – 0.05 W/Mk;
• fire resistance limit – EI 30 to EI 180;
• flammability group - NG;
• density – from 120 to 140 kg/m3;
• specific gravity – from 17.5 to 43.5 kg/m2.

Characteristics roofing slabs with polystyrene insulation:

• sound insulation – from 25 to 39 dB;
• thermal conductivity – 0.042 W/Mk;
• fire resistance limit – EI 15;
• flammability group – G1;
• density – 25 kg/m3;
• specific gravity – from 12.2 to 17.2 kg/m2.

Characteristics of sandwich panels with polyurethane foam insulation:

• sound insulation – from 30 to 35 dB;
• thermal conductivity – 0.022 W/Mk;
• fire resistance limit – EI 15;
• flammability group – G4;
• density – 41 kg/m3;
• specific gravity – from 9.2 to 15.5 kg/m2.

Three-level roofing systems have the ability to withstand heavy loads without compromising the quality of the material. The maximum wind load reaches 48 kgf/m2, the coating can withstand up to 150 kg of snow per 1 m2. The service life of sandwich panels reaches 30 years.

Preparation for installation

High-quality installation of sandwich slabs on the roof is impossible without preliminary preparation of the process. The first step is to familiarize yourself with the design and installation documentation. The project determined the size and type of sandwich panels, the number of slabs, the technological layout map and fastening methods nodes, amount of waterproofing materials.

Before starting installation work, you should check the position of the crossbars, rafters and purlins, eliminate possible differences, and check the angle of inclination of the slope. At the preparatory stage, the necessary tools and related materials are prepared.

Required tools and materials

To trim slabs, fasten materials and seal butt joints during installation work, the following material and technical equipment will be required:

• electric scissors;
• stationary circular saw;
• fine-toothed file;
• screwdriver or electric drill;
• building level;
• long roofing screws made of carbon or stainless steel, equipped with sealing washers;
• short self-tapping screws for fixing additional elements.

The length of the screws for fixing the sheets is selected based on the material of the supporting structure and the thickness of the panel itself. To fasten sandwich panel flooring, self-tapping screws 12.5 mm long are usually used.

In addition to the three-layer slabs themselves, additional elements and forming parts will be required to construct the roof:

• cornice strip;
• end strips and plugs;
• ridge strip.
• valleys.

Sheathing for sandwich panels

Various materials can be used to construct a frame for sandwich panels:

• tree;
• metal;
• reinforced concrete.

The advantages of a wooden support system are its affordable price, environmentally friendly material, low thermal conductivity and ease of assembly. The disadvantages of a wooden base include the need for additional treatment of the material to prevent fire and damage by fungus and insects.

Reinforced concrete supporting structures are characterized by a long service life, high strength, rust resistance and low thermal conductivity. Significant disadvantage reinforced concrete lathing is heavy.

Metal lathing is quickly erected, durable and reliable design resistant to deformation. Negative qualities metal support– high thermal conductivity, the need for anti-corrosion treatment, considerable cost.

The frame structure is designed taking into account the geometric parameters of sandwich panels. The distance between the sheathing runs should ensure that the slabs are fastened 5 cm from the edge, the supports should coincide with the place where the panels join.

Installation technology

Sandwich panels are lifted onto the roof using special equipment. To avoid damage to the material, lifting mechanism must be equipped with load-handling devices in the form of vacuum suction cups or soft grips.

Before starting work, remove from the bottom surface of the slabs protective film. Roofing blocks are mounted in rows in the direction from the roof overhang to the ridge. The panels are fixed to the frame with roofing screws. Fasteners are screwed strictly perpendicular to the sheet, screwed without excessive force, so as not to damage the gasket.

Installation of a roof made of sandwich panels begins from the corner of the bottom row, which in turn forms a cornice overhang. Subsequent elements are mounted with an overlap, fixing them to the already laid blocks and to the sheathing.

The end parts of the sandwich panel are equipped with Z-Lock type locks. The sheets are fixed in the longitudinal direction using locking connections. It is important to ensure that the ridges of the locks fit tightly into the depressions of subsequent slabs. To reliably seal the joints, butyl rubber or silicone sealant is applied to the locking grooves.

After laying the roofing slabs, they begin to install the roof ridge. Sequencing:

1. Installing the inner ridge strip.
2. Filling the gaps between the plates with polyurethane foam.
3. Installation of profile polyurethane gasket.
4. Filling joints with mineral wool or other insulation.
5. Fixation on the ridge of the ridge strip.
6. Installing a polyurethane gasket with a self-adhesive base on the top of the ridge.
7. Installation of the ridge strip using short self-tapping screws.

Minimum slope roofs

In the presence of transverse connections, window hatches and other parts that violate the solidity of the coating, the minimum slope of the roof made of sandwich panels is not less than 7 0 . In cases where a solid sheet fills the entire span along the length, the slope may be reduced to 5 0 .

At the roof design stage, the slope of the slope is selected based on the climatic characteristics of the region. For dry and hot areas, the roof slope can be from 5 to 25 0. In areas characterized by frequent rain, the roofing sheet is laid at an angle of at least 40 0.

When laying roofing sheets on slopes with a slope of more than 15 0, it is mandatory to install additional supports, which prevent the sandwich panels from sliding down.

Installation with transverse joints

The technology for arranging transverse connections includes the following steps: at the panel of the next row, a part of the lower skin and insulation equal to the amount of overlap is cut off. The amount of overlap is determined based on the slope of the slope, for roofs with a slope from 5 to 10 0 - 30 cm, with a slope from 10 to 20 0 - 20 cm. Sealant is applied to the lower plane of the resulting protruding part of the outer skin, the panel is attached to the frame and fastened with laid sheet of the bottom row. The junction of the slabs of the lower and upper rows should be at the frame run. The gap between the sandwich panels must be completely filled with sealants to avoid leakage.

Installation errors and their consequences

Basic installation errors roofing sandwich type:

• inaccuracies in design documentation;
• uneven frame;
• cutting panels with a grinder;
• incorrect choice of screws;
• over-tightening or under-tightening of fasteners;
• neglect of seals;
• incorrect arrangement of abutments and seam connections.

As a result of mistakes made at the installation stage, roof covering leaks occur. Violation of the technology is fraught with a decrease in the wind resistance of the flooring and other technical parameters of the material declared by the manufacturer.

Operating rules and repairs

The operation of a flat roof made of sandwich panels does not require special effort. Operational measures come down to timely removal of debris from the roof. An inspection must be performed once every six months. technical condition coverings. If defects are detected in as soon as possible carry out repair and restoration work.

The most common defect is damage to the polymer shell on outer skin. Special enamels are used for repairing sandwich panel roofs. Paint material For restoration work selected based on type protective coating, color and shade of roofing slabs.

Depressurization of butt joints is a defect that can not only lead to leaks, but also destruction of the insulation. Opened seams must be coated with sealant.

Review of modern manufacturers

The roofing materials market offers a wide selection of sandwich panel manufacturers. The leading positions in the designated segment are occupied by:

• Promkpanel company specializes in the production of sandwich panels for roofs based on mineral wool and expanded polystyrene, as well as shaped elements. Benefits domestic manufacturer is a high quality product and an affordable price per m 2 of roofing;
• Petropanel company supplies sandwich panels with mineral wool insulation to the domestic market. The production of three-component roofing slabs is carried out using equipment from the English company ISOWALL;
• Kraft SPAN company produces high-quality roofing panels with high levels of fire resistance, tightness and strength. Basalt mineral wool was used as an insulating layer. The company's production base is equipped with equipment from the Australian company Hilleng;
• Izobud company - the company’s products have been represented on the building materials market since 1998 and are widely known both in Russia and abroad. Roofing materials undergo strict control to ensure compliance with international standards and sanitary and hygienic standards. The manufacturer supplies the market with sandwich panels for roofing with insulation made of mineral wool and polyisocyanurate foam;
• Vesta Park company has been repeatedly nominated at various competitions in the field of building materials. The advantages of Vesta Park products are high quality that meets international standards, a wide selection color range sandwich panels, loyal pricing policy.

Sandwich panels have found wide application in roofing of industrial and agricultural buildings, retail facilities, and sports facilities. Properly designed and correctly installed decking made from three-layer systems will serve as reliable shelter for many years.

Sandwich panels are modern version roofing material. Installation of roofing in the form of multilayer panels is simple, since the material weighs little. Light weight is both an advantage and a disadvantage, since strong gusts of wind can tear off the coating.

In three-layer roofing panels, the outer layers are profiled metal (thickness 0.5-0.7 mm), and inside there is a heat insulator (fiberglass, mineral wool, polystyrene foam or polyurethane foam). All layers of a sandwich panel are a single product; the layers are joined using glue or pressing.

Advantages of roofing sandwich panels:

• Good noise and heat insulation;
• Original appearance;
• Fire resistance;
• Service life more than twenty-five years;
• Versatility - there are elements of different sizes.

Installation features

The roof that is planned to be covered with sandwich panels must have correct slope. The slope of the roof is prescribed in SNiPs; improper roof design reduces the service life of this roofing by almost half.

• If the roof has windows or skylights, the slope should be greater. In this case, calculations are carried out on an individual basis.

Problems when choosing the wrong slope of roof slopes:

• Rapid wear of the material, deterioration of operational parameters;
• The occurrence of water stagnation;
• Poor waterproofing, roof leaks;
• Loss of aesthetic appeal.

03.04.2016 02:39

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Last revision: 10/26/2016

A modern roofing structure cannot be perfectly flat, since precipitation in the form of snow or rain must be drained from its surface in any case. That is why, when installing flat roofs, it is necessary to comply with the so-called slope rule, which provides for a slight inclination of the flooring to one side. The presence of such a slope allows rainwater to be drained from the surface of the coating and collected from roof fencing, where special drain holes are prepared in advance for these purposes. The minimum roof slope, as a rule, is selected taking into account the following parameters of the installed coating (its performance indicators are also taken into account):

• roofing material used;
• type of roof (classical or inversion);
• number of waterproofing layers;
• average annual precipitation (snow load);
• wind loads on the structure.

SNiP requirements

The dependence of the angle of inclination on various factors is regulated by special building codes and rules (SNiP). Among the requirements for the slope flat roof SNiP II-26-2010 “Roofs”, especially important the following provisions regarding its dependence on the coating material:

• depending on the type of waterproofing used, the angle of inclination of the roof can vary from 1.5 to 10º;
• angles of inclination of greater magnitude (up to 2º) are chosen very rarely, which is explained by the difficulty of selecting a soft covering that would not slide to the base of the roof when high temperatures air;
• The minimum slope of the so-called flat roof should be at least 1–1.5º.

Note! There is a certain relationship between the slope of the roof structure and the number of layers of waterproofing coating laid on it. The more significant this value is, the faster precipitation will be removed from it, and, therefore, the number of waterproofing layers may be less.

The roofing materials used to cover the roof differ in their structure, according to which they have a more or less smooth surface. If the coating structure is not smooth enough (rough) the likelihood of both water and snow retaining on it increases noticeably.

This is what determines the dependence of the minimum slope angle on the roofing material used. Next we will consider the specific values ​​of this indicator for various types coatings

The smallest angle of inclination of the slope when arranging a roof made of tiles is usually chosen to be at least 15º (for some models of material this value can be 14º). If it is necessary to reduce this indicator, some manufacturers advise treating the joints of metal tile sheets with a special waterproof sealant that retains its properties at low temperatures.

Note! If the slope is too gentle, precipitation will be retained in certain areas of the roof and seep into the joints during heavy rains. And this will lead to additional load on the roof in those areas where they are delayed.

This disadvantage can be partially eliminated by using tile samples with a higher wave height.

When using this type of roofing, the indicator we are considering should have a slightly lower value (as a rule, it is equal to 12º).

In the case of making roofs from corrugated sheets with a lower slope, when laying them, it is necessary to observe the so-called two-wave overlap, and at angles of the order of 15º and above, an overlap of 20 cm will be sufficient. At the same time, as the angle of inclination increases, the pitch of the sheathing laid under the covering should also increase.

When the roof slope is at a minimum (i.e. when it is almost flat), continuous sheathing should be used to increase the load capacity of the supporting structure.

There are several types of soft roofs, differing in the material from which they are made:

1. Flexible tiles. In the case of using the so-called soft roof as a covering ( flexible tiles– in particular) the sheathing under it should be made in the form of a solid base made of plywood sheets (OSB). Minimum value the slope of the slopes for this type of roofing is at least 11º.
2. Bitumen coatings. For soft coverings of this category, the minimum roof slope has the lowest value (its value, as a rule, does not exceed 2º). But at the same time, as noted earlier, you will need to increase the number of layers being laid. In the case when technical reasons it is not possible to lay more than 1–2 layers bitumen material– you will have to increase this figure to 15º. The minimum angle of inclination of a coating made on the basis of ondulin, as a rule, does not exceed 6º. This roofing material is the most preferred for covering roofs with low pitches, but to install it you will need a continuous type of sheathing.
3. Clay tiles (slate). When laying hard clay tiles or classic slate sheets, which have an uneven surface that holds snow well, the slope of the slopes should be at least 22º. In this case, it is necessary to pay very close attention to the calculation of the rafter system, which, due to the large weight of the material, will experience significant loads. In addition, we should not forget about additional loads on the rafters, which are possible when large volumes of snow accumulate on the roof, as well as during powerful gusts of wind in bad weather.

Taking into account all these factors, the requirements for load capacity roofing system increase significantly.

Note! When making roofs from tiled or slate covering with a slope angle of less than 22º you will have to recalculate the entire rafter system, since the loads on it in this case increase many times over.

According to SNiP requirements, the minimum slope of sandwich panel flooring should be approximately 5º (provided that the covering is continuous and has no joints along its entire length). Let us immediately make a reservation that this indicator is valid only for cases when the roof does not have built-in windows or other elements that violate the integrity of the continuous covering.

In the presence of all the specified violations of the integrity of the flooring minimum angle The slope of such a roof must be at least 7º.

Even at the design stage of a future roofing system (and, in particular, when choosing a roof design option with a certain angle of inclination), it is necessary to take into account climatic features your area. If precipitation occurs quite frequently in your area, the minimum steepness of the slope for the sandwich panel should be at least 40º, since only with such a slope of the roof will rain moisture not be retained in the joining seams. Well, in areas with low average annual precipitation, a slope of about 7–22º is considered optimal.

Note! Before installing roofs with large slopes, you must take into account the fact that in this case you need more building material.

On the other hand, if this indicator is too low, water will accumulate on the roof, which over time can destroy the waterproofing seals of the panel joints. And in the off-season (with the onset of thaws and frosts), ice build-ups form from the accumulated moisture, which can damage the protective layer of the sandwich panels, as well as their metal shell.

With a slight roof slope (less than 7º), there is no need for additional fastening of panels to frame basis made of reinforced concrete, wood or metal. On roofing structures with a large angle of inclination, additional fasteners are required.

You may also be interested in these materials from our site:

• What is an inversion exploitable roof?

Video

From this video you will learn how to make a roof slope.

Today, many traditional roofing coverings are being replaced by new technologies, which are significantly different in nature from the old ones. For example, quite reliable insulated roofs are obtained from elements such as roofing sandwich panels. Their capabilities are very wide, and therefore in Russia warehouses and commercial buildings are actively being built from them, residential complexes and special objects.

Wherein modern roofs made from sandwich panels look quite stylish and from a distance resembles classic roofing materials. But at the same time, they are much more functional, because they combine three components at once: the roof, the insulation, and even finishing coating below. In general and economically, such sandwich panels are more profitable.

If you are interested in this technology, let's take a closer look at it and get some interesting ideas for ourselves.

A modern sandwich panel is a structure of three layers, where the insulation is located between two profiled metal sheets:

Let's take a closer look at the profile itself:

• on the one hand, the panel has stiffening ribs, presented in the form of special trapezoid-shaped protrusions, usually 40 mm high.
• on the other hand, the panel has a micro-profile with a depth of 1.5 mm.

Let's move on to technical specifications sandwich panels. So, today the sizes of roofing sandwich panels vary from 1000 to 1120 mm, length - from 2 to 14 meters, much depends on the equipment.

The sandwich panels themselves differ from each other as follows:

• according to the installation site: roofing and wall, ceiling and universal;
• if possible, loads: self-supporting or facing;
• at the assembly site: those that can be assembled directly at the construction site, products of element-by-element assembly, and those that are manufactured in a factory and delivered to the construction site ready-made.

By the way, the very first designs of roofing panels had two types of connections along the edges of the sheets: a standing seam or a seam with internal elements. Of course, such systems had many disadvantages.

For example, the outer metal sheet was flat, with slight profiling, and therefore it sagged under the weight of the snow cap, and was deformed by the hot rays of the sun. Because of this, microcracks appeared in the corners of the bends.

Officially, this is called “low cycle fatigue” of the metal. It was impossible to move in such places without damaging the outer sheet and the insulation itself. In addition, the very quality of the seam seam often left much to be desired, because such manipulations with metal require high professionalism.

Modern panels differ significantly from them:

• Firstly, the fastening of roofing sandwich panels itself is now different.
• Secondly, today the minimum slope of a sandwich panel roof is 5-7 degrees, and more than 12 is recommended.
• Thirdly, today such roofing sandwich panels are subject to the same requirements as for conventional roofing.

Namely, to ensure the sealing of all joints, drainage and protection from bad weather. With such panels, all this is realized using a special lock.

By the way, the panels themselves are produced in a whole series, with the most different properties:

Single assembly panels: simplicity and reliability

Roofing sandwich panels of element-by-element assembly are easily assembled multilayer structures that consist of a cassette, a metal base of insulation, special hydro-wind protection and external cladding. We can say that this is a kind of semi-finished product, because these panels are finally assembled directly at the construction site.

This design is based on cold-rolled or hot-rolled steel with a thickness of 0.71 millimeters. An additional polymer coating is often applied to it. In appearance, this again resembles a box, the bottom of which will serve as the ceiling of the under-roof room.

Inside such a box is mineral wool or basalt fiber, located with slight tension. On top of the insulation is hydro-wind protection in a special vapor-permeable membrane.

Monopanels: thoughtful design

You will be interested to know that today they are already producing sandwich panels that form a soft roof, and only their inner side is metal. This is a design called a “mono-panel”.

It is from such panels that the roofs of commercial buildings, sports facilities and industrial buildings are often built. In such a panel, the inner side is load-bearing and at the same time also serves as a ceiling lining.

It is made on the basis of a steel sheet coated with zinc (polymer, too, if possible). Penoizol, a special casting foam with flammability group G1, is used as insulation here. This group indicates low flammability, when the panel does not burn, but only chars.

Let's list the main advantages of monopanels. So, they can be:

• install on roofs with absolutely any slope, and quickly enough;
• transport by any means of transport;
• apply in buildings of the second degree of fire resistance;
• carry out everything installation work over a fairly wide range of humidity and temperature.

At the same time, the panels can be cheaper than other types of sandwich panels.

Today, two main types of monopanels are produced - with soft coating and metal. Thus, with polymer roll material, sandwich panels have a perfectly smooth surface on which snow does not accumulate on the roof at all. It is reliable and durable, and all external joints and junctions are sealed with modern compounds.

The metal covering for monopanels is made on a machine with special longitudinal flanges, in order to then bring them into a double standing seam using a seaming machine.

Sip panels: proven material

In Russia, until recently, there was experience in using only roofing sip panels, which are also classified as sandwich panels, although sometimes experts call them different materials. But here, just like in a classic sandwich panel, there is insulation between two rigid sheets.

We are talking about a structural thermal insulation panel, which is used for the construction of prefabricated housing. She represents monolithic structure, in which two oriented strand boards OSB-3 and expanded polystyrene are glued together under pressure.

Moreover, such panels are very durable and light at the same time. So, the mass of one square meter is no more than 15 kg, but this square meter capable of withstanding vertical longitudinal pressure of more than 11 tons!

In Russia, such construction is also still a little new, although it is gaining popularity day by day. But there is one more difference from a regular sandwich panel - the sip panel does not use a vapor barrier or windproof membrane. Here the OSB-3 board is glued as if to the insulation itself, and does not warp over time.

What’s interesting is that abroad there are quite often variants of sip panels with OSB sheathing only on one side, and on the other side there is a metal sheet.

Moreover, in Russia they are still trying to find an analogue for such panels, replacing OSB with cement-bonded particle boards, fiberboards or glass-magnesium sheets. But there are some points here: self-tapping screws in panels based on a mineral binder do not hold well and are often subject to corrosion, which does not happen with OSB-3.

Internal contents and characteristics

So, what are these panels made of? Let's look at their structure!

External coating: weatherproof

Quite often, for the internal and external cladding of such roofing sandwich panels, they are used metal sheets shaped by repeated bending. Much less often, such cladding is made of corrugated sheets.

The profile of the top sheet itself is usually flat, almost flat and with fairly high trapezoidal projections to ensure proper drainage. The higher the projections, the more they reduce thermal deformation of the panels, but the more expensive they are:

Here are the main types of profiling of such panels:

The most significant difference between roofing sandwich panels is their coating. Moreover, high demands are placed on the cladding of sandwich panels, because the finishing coating takes on all operational loads. These are both climatic and dynamic, when workers go out onto the roof to repair it or clear snow.

On the Russian market, almost all three-layer sandwich panels have steel external cladding, from cold-rolled steel sheet from 0.4 to 0.7 mm. Here the zinc coating is applied hot and has a thickness of 25 to 50 microns. Next, several layers of polymer coatings with a total thickness of 25 to 200 microns are applied to the surface of the zinc. There can be up to eight such layers in total.

So, when high color retention and resistance to dirt are required, a polymer coating is used. For example, the popular coating Hiarc. Its subspecies Hiarc Matt pleasing to the eye beautiful color with a matte surface, which gives the roof a special expressiveness. Sandwich panels are also produced in metallic colors.

The next type of coverage is High Build– this is a thicker primer layer with a special pigment that is resistant to mechanical damage.

Another coating is polyester enamel, or polyester. It suits almost everyone climatic zones, resistant to atmospheric mechanical influences. But one cannot call it too reliable.

This coating is used in cases where sandwich panels do not have increased requirements for corrosion resistance. But, if we talk about the roof, this option is not acceptable; this material is more suitable for interior spaces than for exterior ones.

Pural – This is a coating based on polyurethane resin. Looks pretty thick layer with high wear resistance.

Polyvinyl– polymer coating with particularly high corrosion resistance and resistance to ultraviolet radiation. It retains its color and shine longer than all types of coating, and withstands molding remarkably well.

Choice of insulation: bubbles or cotton wool?

Sandwich panels use basalt mineral wool, glass wool, expanded polystyrene, polyurethane foam and their varieties as insulation:

Also, for monopanels, they also use a type of insulation such as penoresol. In this case, the insulation is various densities depending on what thermal insulating properties it should have. The thickness of such products is selected according to the exact thermal engineering calculation, usually from 40 to 300 mm.

In cross-section, all these panels look like this:

If you want to go deeper on this issue, watch this video review:

Let's note the advantage of basal mineral wool. And sandwich panels are laid so that the fibers are oriented vertically. This design turns out to be the most stable and does not threaten shrinkage of the insulation.

Due to this, the density of sandwich panels is in the range of 90-140 kg per square meter, and the thermal conductivity coefficient is 0.043 W/m2. But at the same time, which mineral water is still the heaviest of all types of insulation used.

Another option is glass wool. Such panels are slightly lighter than those with mineral wool, and their thermal conductivity is 10% lower. They are allowed to be used at temperatures above 400 degrees Celsius.

But the lightest sandwich is polystyrene foam panels. Its thermal conductivity coefficient is only 0.0022 W/m2, which is very small.

But its analogue, polyisocyanurate foam, is no less high-quality. Polyisocyanurate foam differs from conventional polyurethane foam in that it has higher fire resistance. In fact, this is its modified analogue:

If we talk about the main difference between types of insulation, the main one here is fire safety. So mineral wool sandwich panels are more heat resistant, they are assigned class EI240. But polyisocyanurate foam panels have a fire resistance limit of EI60.

Also important point: element-by-element roofing panels come with additional insulation or without it at all. So, if the thickness of the standard insulation is considered insufficient, then it is changed with the help of another heat insulator.

Here, Z-shaped purlins with a height of 50 to 200 mm are installed on top of the main insulation inside the base and UPTP strips are glued to avoid cold bridges.

In this case, the purlins are mounted across the rafters. Inside such purlins, the required number of layers of thermal insulation is placed, then a hydro-wind protection and shelves of Z-shaped purlins are mounted on top of the additional insulation. And sheets of the selected roofing covering are attached to the shelves themselves.

The internal filling of the panels affects their fragility:

Reliability of the adhesive connection

All three main elements of sandwich panels are connected to each other with a special elastic adhesive composition. Moreover, the choice of glue here is approached with full responsibility, since, for example, the same basalt-based insulation is a fairly porous material with a fragile surface. Therefore, it is important that the glue can penetrate deep into the roughness of the insulation and fill the voids between the fibers and the metal.

As you understand, quite a lot of glue itself is used here, and in foamed form, after which it hardens. At the same time, it is important that the glue is moisture resistant, not afraid of atmospheric influences and can withstand temperature changes well.

All these requirements are met by modern polyurethane-based adhesives, which usually connect metal to other materials. In this case, one-component and two-component compositions are used specifically for roofing sandwich panels.

The service life of sandwich panels is limited by the service life of the adhesive layer itself, namely its destruction. By the way, sandwich panels with polyurethane insulation are sometimes made without glue at all, connecting the components together using a special molding. It is impossible to say whether this is better or worse - time will tell.

See what finished sandwich panels produced in production look like:

Important details of fastening

The next point: fasteners on roofing sandwich panels are made visible or hidden, and the lock is ordinary or with increased energy efficiency, which is provided by a special seal.

Roofing sandwich panels are connected to each other in the following basic ways: single seam with additional insulation, double seam, lock (for example, Roof-lock), and using a special trapezoidal head made of galvanized steel. The installation technology itself is dictated, naturally, by the manufacturer.

To close a single and double fold, you need special tool called "frame". Locking modern panels requires no tools at all.

The most convenient one is, of course, a lock. But there is a drawback here: sandwich panels, which were originally designed for such locks, have an easily deformed element along their entire length, which is not difficult to touch during installation or storage. So to speak, his weak point.

This is what the fastening of polyisocyanurate foam panels looks like:

This is how mineral wool panels are attached:

What is good about the “roof of the future”, or pleasant advantages

First of all, for the construction of a roof, it is of great value that roofing sandwich panels allow installation at large steps between purlins. This in total greatly reduces the overall cost of constructing the roof itself.

That is why the use of sandwich panels primarily lies economic expediency, which allows today to erect such roofs on almost all types of buildings. Bye on this moment the only exceptions are apartment buildings, but this, according to experts, will not last long.

You will also be surprised that despite their apparent fragility, roofing sandwich panels are quite durable material, excellently withstands wind and snow loads. At the same time, roofing sandwich panels do not create any special additional load on the foundation:

We also note that such panels are quickly and easily installed, and just as easily dismantled. They do not require any finishing or special fasteners.

Disadvantages, shortcomings and other annoying facts

Despite all the advantages, sandwich panels have a number of disadvantages. For example, their use of three-layer panels is predicted to decline over time, giving way to other types of sandwich panels.

Here is an entertaining video tutorial on the advantages and disadvantages of roofing sandwich panels:

Features of the northern climate

The Russian climate is quite aggressive, especially in the north. And therefore, many roofers are still afraid to use roofing sandwich panels due to seasonal temperature fluctuations, which cause significant stress during operation.

The second point is that when placed on the roof in direct sunlight, the sandwiches change their size. This is a natural process for metal surfaces, but it is extremely necessary to take it into account when adjusting the angles of joints and seams so that the entire system does not eventually fail. It’s just that element-by-element sandwich panels are free of these disadvantages.

After all, it is not the mineral wool that takes the load on them, but the box-shaped frame itself, thanks to which lighter and cheaper thermal insulation can be used. Yes, such elements provide more reliable sealing of the roof and the ability to remove condensate through an organized ventilation gap.

In addition, during the process of cyclical temperature transitions through the so-called “freezing point of water,” the mineral wool insulation block is gradually destroyed and the fibers are blown out. As a result, the load-bearing capacity of the structure itself is lost.

Also, mineral wool itself is subject to physical aging, and yet it bears the entire operational load. At the same time, unfortunately, the actual fire resistance of such a roof is low.

Firstly, the maintainability of such panels still raises questions. If a problem arises, the entire roof will have to be dismantled, so repair costs will be significant.

Installation errors and their consequences

Further, while the locks of such panels leave much to be desired, and if used not very carefully, they can be unreliable. As we have already said, the accuracy of fastening and the tightness of the future roof are ensured by special grooves in the seams. And the main problem with installing sandwich panels is whether the joint turned out to be successful or unsuccessful.

That's why manufacturers are constantly working to improve such locks. After all, the strength of the connection of such panels on the roof, the absence of gaps, and tightness depend on this.

For a roof, these are critical indicators. And any unsuccessful joint can become a conductor for rain moisture and a bridge of cold, while for the same walls all this is not so important:

In bad weather conditions and frequently changing humidity and air temperature, cold bridges and leaks occur on poorly laid sandwich panel roofing. The sheathing also peels off from the insulation if a foam sandwich is used and the flammability of the middle layer increases, and if the insulation is made of mineral wool, the destruction of the bond between vertically oriented fibers due to moisture is noted.

They can lead to sealing of the longitudinal joint and further damage to the entire coating. Moreover, such damage is not so easy to detect by eye, and even more difficult to correct.

Although in fact, when working with sandwich panels, it is quite possible to avoid all the listed points and disadvantages if you strictly follow all installation rules.

Difficulties in transportation and storage

And finally, roofing sandwich panels have such a serious disadvantage as they are easily damaged during transportation and installation, so they must be handled carefully, especially with care. That is why manufacturing companies often provide complete roofing services themselves, from design to installation.

And we advise you to resort to such services, since a professional team already knows all the intricacies of working with this new roofing material; there are even a whole host of recommendations even regarding the storage of the panels themselves.

By the way, what manufacturers are most worried about is that in our country installation rules are often neglected and roofing panels sometimes get wet even before they reach the roof. In this case, the fibrous insulation quickly loses its properties and is destroyed during subsequent seasonal freezing and thawing processes.

It is thanks to such doubts that the owners of their houses still universally give preference to the more classic and proven “correct” pie, where the insulation has its own specific place and there is always access to it. At least, if the cotton wool gets wet here, the load-bearing capacity of the roof will not decrease - the problems will simply be different.

Installation stages: unusual technology

Let's look at the principles of installing roofing sandwich panels on the roof. Thus, three-layer roofing sandwich panels are used for buildings with a roof slope of no more than 12 meters and a slope of at least 12%. They are laid on purlins in increments of one and a half meters.

Compared to classic sandwich panels, monopanels are suitable for creating any area and any angle of inclination, and the pitch is allowed at 3-4 meters.

Here's what installation of such a roof looks like in practice:

It is most convenient, of course, to use one panel on the roof slope so that it does not have any transverse joints. Although today it is not uncommon for such sandwich panels to be assembled on the roof like a construction set, with an overlap. In this case, the panel is laid upward, as if along pillars.

This roofing covering is secured using hat profiles across the rafters. The panels are laid along the rafters along the purlins. And so that cold bridges do not form at the junction, here a thermal separation strip made of isolon is fixed on top of the membrane along the shelves themselves.

The roofing sheets of monopanels are secured to each other using clamps, and the clamps themselves are connected with self-tapping screws. Such a panel is installed along purlins up to 4 mm and secured with self-tapping screws:

Further, on top of it it is allowed to make a soft roof from ordinary traditional materials, for example, from piece shingles. The monopanels themselves are convenient in that their installation can be carried out by any builder without special qualifications, and at almost any time of the year.

The roofing panels themselves are installed along purlins or secured with bolts, or alternatively with self-tapping screws with a special washer. The most practical are considered to be a spike type connection, a heat-insulating harness and special ties.

The hat profile itself is determined by the design of the roofing itself, and for metal tiles it is equal to its pitch.

Sandwich panels are fixed to the walls of the house using the same additional elements as in the case of a conventional roof:

Here are the main components of such a roof:

This is how a roof overhang made of sandwich panels is designed:

Here are the main options for organizing drainage for such a roof:

The highest quality sandwich panels, according to manufacturers, last 25-30 years. At the same time, it is extremely important that during installation and transportation of the panels they are not damaged, and that the joint is sufficiently sealed.

It is on the domestic market that options with trapezoidal protrusions on sandwich panels, also called roofing profiles, predominate.

Compared to the rest of the world, in Russia they still produce roofing sandwich panels in the following ratio of insulation: 85% mineral wool and 15% polyurethane foam. But in the world it’s the other way around: 80% of such panels are made of polyurethane foam or polyisocyanuate foam, and only a fifth are made of mineral wool. Although foam insulation is lighter.

Thus, the highest quality products are supplied to reviews Russian market companies such as Promkpanel, Petropanel, Kuznetsk Metal Structures, Techno-Izol and Azna-am. We will also consider the products of such famous manufacturers, like Ruukki, Isobud and Kraft SPAN.

The well-known company "Izobud" has been producing sandwich panels for prefabricated buildings since 1998 and today is on the list of the most famous manufacturers of this roofing material in the Russian Federation.

And it produces sandwich panels from mineral wool and polyisocyanurate foam:

Here are the panels from Isobud made of mineral wool:

Kraft SPAN: new equipment

Kraft SPAN is a company from St. Petersburg that produces wall and roofing sandwich panels made of mineral wool. They have high load-bearing properties, which are especially valued by designers.

It uses profiled steel sheets, mineral basalt wool and fireproof adhesive with safety class Co. It is Kraft SPAN that produces a single series of such panels - FF.

This construction technology has more and more supporters every day. Which is no wonder, because they are attracted by the beautiful appearance of the roof made of sandwich panels and the relatively low load on the load-bearing structures and foundation of the building.

In addition, the modern market today is oversaturated with such panels, thanks to this there remains high competition, and manufacturers pay more attention to product quality. As well as additional related services, such as roof design and repair.

Would you like to have such an unusual roof?