Metal roofing. Practical metal roofing Types of metal roof coverings
Among the huge variety of roofing coverings, the metal roof on the house is especially popular. This roofing option has a number of advantages, the most important of which is reliability. In addition, today, in addition to traditional metal coatings, new types of materials with polymer coatings have appeared. Such coatings not only improve the appearance of the roof, but also increase its protective qualities.
Metal roof coverings are profitable, reliable and beautiful. There is hardly a homeowner today who would disagree with the above statement.
Indeed, it is difficult to find a roofing material that would have better strength characteristics than metal coatings. And thanks to the variety of options, metal roofs on houses can have a wide variety of looks, so each home owner can make their roof covering different from others.
Types of metal roofing
The entire variety of metal roofing materials can be divided into two groups:
- Flat or sheet coverings that are assembled using seam technology.
- Various metal profiles for roofs. This group of materials includes corrugated sheets and metal tiles.
Based on the type of material, metal roofs can be divided into:
- Steel coatings. This option of roofing material is used most often due to its affordable price.
Advice! To protect steel coatings from corrosion, protective coatings are used. Typically, these are zinc coatings, but recently the application of an additional protective layer of polymer is more often used.
- Coatings made of non-ferrous metals. Today, roofing coverings made of copper, aluminum, and zinc-titanium are used.
Characteristics of the most popular metal roofing coverings
Let's look at the characteristics of the most popular options for metal roofing materials.
Galvanized smooth steel
Galvanized roofing steel is a material that has already established itself on the market as a reliable coating that can last 20-30 years. This type of roofing material is manufactured in accordance with GOST 14918-80. Main dimensions:
- Thickness – 0.5-0.8 mm;
- Width – 51-125 cm
- Length – 71-300 cm.
Galvanized steel is a corrosion-resistant material due to the presence of a zinc layer, which must have a thickness of at least 0.02 mm. A zinc layer is applied to a steel base by electrolytic deposition or by hot method - by immersing prepared steel sheets in a bath of molten zinc.
Advice! Zinc coating obtained by hot-dip galvanizing is more resistant and retains its protective properties longer.
When transporting the material and during its installation, it must be handled with the utmost care to prevent damage to the zinc layer. Otherwise, a corrosion center will quickly form at the site of damage, which will destroy the material. To give a galvanized steel roof a more attractive appearance, as well as for additional protection, it is recommended to paint the coating regularly.
During the installation process, galvanized metal sheets for the roof are connected to each other by forming folds - joints in which the edge of one sheet is bent around the edge of another.
To fasten the covering to the sheathing, clamps are used - strips that are cut from the same steel. The stripes are folded on one side. At the point of bend they are nailed to the sheathing, and the straight part of the clamp is used to create a fold connecting the steel sheets laid on the roof.
Profiled sheets
Corrugated sheets are produced by cold rolling steel sheets to form a linear profile. The corrugated sheet can have corrugations of different shapes. Most often, material with a trapezoidal, rectangular or wave-shaped shape is used for roofing coverings.
Corrugated sheeting can be made from galvanized steel, but for covering private houses it is more practical to use material with a polymer coating. This version of corrugated sheeting looks more attractive and is more resistant to external influences.
Corrugated sheets are available in a wide range. To cover the roof, as a rule, they use wall corrugated sheeting (marked with the symbol “C”) with a maximum (21-35 mm) corrugation height or a universal type of material (marked with the letters “NS”). The thickness of the roofing sheeting varies between 0.5-0.7 mm.
The width of the sheets of material can vary from 75 to 115 cm, and the length is selected by the customer according to the size of the slopes of the roof being equipped. The maximum sheet length is 12 meters. A corrugated sheet roof is installed by laying the material on a wooden sheathing. The sheets are secured using roofing screws.
Metal tiles
This version of profiled metal roofing material differs from corrugated sheets by the presence of a shaped profile. Most often, the profile of a metal tile looks like a coating assembled from natural tiles, but there are other profiling options. Unlike corrugated sheeting, metal tiles are always produced with a polymer coating, but the composition of the polymer may be different. Possible options:
- Polyester. This coating option is available in two versions - with a glossy and matte surface. Polyester has an average degree of resistance to mechanical and atmospheric loads, but, due to its affordable cost, is very popular among consumers.
- The coating is based on polyvinyl chloride - plastisol. This polymer is applied to the base in a thicker layer - 200 microns. For comparison, the polyester coating has a thickness of 25 microns. It provides good protective properties, but is not very resistant to significant temperature changes.
- Polyurethane based coatings. An example of such a coating is the Finnish polymer Pural. This type of polymer is applied to the base with a layer of 50 microns, but it provides excellent protection of the base from damage. The disadvantages of this coating include its insufficiently high ductility.
- PVDF is a relatively new coating based on polyvinyl fluoride, which has excellent protective qualities. Its main disadvantage is the high price.
Advice! There are other types of polymer coatings for metal tiles. For example, material with a composite coating, which in addition to the polymer includes mineral granules, is becoming increasingly popular. This coating is extremely resistant to external damage.
Metal tiles, like corrugated sheeting, are produced in different lengths, so they can be ordered in accordance with the dimensions of a specific roof. The technology for laying metal tiles is in many ways similar to the method of attaching corrugated sheets.
The material is laid on the sheathing and secured to it with roofing screws. During the installation process, it is very important not to damage the polymer coating of the material, as this will not only spoil the appearance of the roof, but will contribute to the development of corrosion of the base at the site of damage.
Caring for metal roofing
Like any other structure, metal roofing requires regular maintenance. To ensure that the coating lasts a long time, it is recommended to inspect the coating twice a year to identify defects.
Typically, roof inspections are planned for mid-spring, when the snow melts and warm weather sets in, and in October-November, that is, in preparation for winter. The purpose of the inspection is to timely identify defects for their subsequent elimination. In addition, the list of care activities depends on the time of year.
Summer care
Dust, as a rule, does not linger on smooth metal coatings, as it is washed off by rain. However, other contaminants may remain on the roof surface - branch leaves, etc.
Debris lying on the roof contributes to the destruction of protective coatings and the formation of rust, so in the summer it is worth periodically cleaning the roof of accumulated debris.
Cleaning should be done using soft brushes that cannot scratch the polymer coating of the material. You can wash the roof using a car wash using a stream of water under pressure.
If large stains appear on the coating, you can use special detergents for the care of polymer coatings to remove them. In the fall, you should definitely check the condition of your roof's drainage system, as gutters and drains often become clogged with falling leaves and other debris.
Winter care
In winter, a thick layer of snow or the formation of ice build-up can pose a threat to the coating. Ice dams, as a rule, form if mistakes were made during the assembly of the roofing pie, in particular, if there was insufficient ventilation.
If the snow cap on the roof is too large, then it is better to remove it. But in the process of clearing snow from the roof, you need to be extremely careful not to damage the polymer coating of the material. To do this, it is recommended not to completely remove the snow, leaving a small layer on the roof.
So, metal roofing is practical, reliable and profitable. Thanks to a wide range of metal roofing coverings, you can solve various design problems. Proper care of the coating, regular inspection and timely minor repairs of a metal roof aimed at eliminating emerging defects will significantly increase the service life of the coating.
“Roofing iron” is a simplified name for a category of materials that are attractive due to their light weight, low and relatively low cost. Among the advantages are the large dimensions of the elements, which makes installation easier and increases the pace of roofing work. A very convincing argument is fire resistance and tightness, justified by the complete absence or minimum number of holes for fasteners. It’s not without reason that the list of advantages includes ease of installation, thanks to which the owner can build a metal roof over a country bathhouse with his own hands.
Types of Metal Roofing Sheets
Over centuries of metal use as roofing, many technological variations have been created. Instead of the simplest sheet iron, aluminum or copper, you can now use unique “constructors” produced in factories with a full set of fasteners, additional parts and elements for arranging connections.
The conditional classification of roofing iron divides all currently existing types of metal roofing into the following groups:
- cold-rolled, thin-sheet or rolled, black or galvanized steel, used for the installation of budget seam roofs;
- fully prepared for installation, attracting with an abundant range of modifications of different colors and shapes of elements, and corrugated sheets with similar priorities;
- non-ferrous metals, the group of which includes coatings made of copper, titanium-zinc alloy and aluminum.
Let’s put aside the advantages of convenient and technologically advanced roofing sets made of metal tiles and corrugated sheets due to their high cost. For the same reason, let's temporarily forget about non-ferrous metals. Let's consider the most economical independent installation of a metal roof, the implementation of which will require steel sheets with a strip length of 2.50 m and a corresponding width of 1.25 m.
It is recommended to buy steel for roofing with double-sided galvanization. It is more expensive than its “black” non-zinc coated counterpart, but the money invested in the material will be returned due to rare maintenance and optimized wear resistance. According to the hot-dip galvanizing method, cold-rolled material is completely immersed in containers with molten zinc, as a result of which a dense protective layer is evenly deposited on its surface.
The material thickness values are dictated by the building code: metal roofing (SNiP II-26-76), in accordance with the requirements of building regulations, is constructed from a thin-sheet product from the rolling industry. For roofs, steel with a thickness of 0.5 mm to 1.5 mm is purchased. It will be easier to work with the thinnest sheets; they are easier to bend to form joints. But if the owner plans to make additional parts and drainage elements from the same material, a thickness of 0.6 mm to 0.8 mm is recommended.
Note. Building rules do not prohibit, but also do not recommend distorting the shape of galvanized sheets, as a result of which the integrity of the zinc coating may be disrupted. According to the requirements of SNiP number 3.03.01-87, metal tools during work cannot be placed on a galvanized surface without a wooden lining. Damage to the zinc protection will cause loss of performance.
Independent device and installation
The most common and economical type of laying metal sheets on the roof is called seam technology. The name and principle of construction is based on the method of connecting elements with repeatedly curved edges, forming longitudinal and transverse seams - folds.
- Transverse seam joints are used if the horizontal size of the slope exceeds the standard length of a steel sheet of 2.5 m. They can be single or double; they are called horizontal because they have the same direction, and recumbent because they are bent in the direction of water drainage from the roof so as not to create barriers to spontaneous drainage of precipitation.
- Longitudinal seam seams connect the roofing elements along the imaginary vertical of the slope, that is, along the side line of the sheet. They are not bent because they do not obstruct the flow, which is why they are called standing. By analogy with the previous connections, they can be double or single. Not a single installation of metal roofing using seam technology is complete without horizontal standing joints.
Horizontal connections, especially if they are single, reduce the ability of the structure to resist atmospheric negativity. If possible, it is advisable to exclude them. Standing double seams are recognized as the most reliable and practically airtight. You can form a seam either using a hammer and a wooden screw, or using special electromechanical seam rolling machines or manual comb benders.
Specifics of standing seam roof construction
Its main element is the painting. This is a part assembled from two adjacent steel strips with curved edges necessary for subsequent connection. The paintings are collected on the ground. To assemble them, it is advisable to make a special workbench with a length equal to the length of the parts of the picture to be connected.
To splice the paintings and attach the outer panels to the sheathing, you will need homemade clamps - strips cut from the same steel with side dimensions of 3 and 15 cm. They are attached every 0.5 m next to the vertical seam line. Taking this fact into account, you need to make the required amount of fasteners from scraps of steel sheet.
Attention. Galvanized steel parts are cut with scissors. The grinder leaves an uneven jagged edge and burns out the protective coating.
The paintings, assembled in a safe environment with the edges prepared for joining, are lifted up, but first the base for their installation is prepared.
Construction of the rafter system and sheathing
The rules for constructing a rafter system for a metal roof are no different from the technologies for constructing frames for other roofs. Only due to the lightness of the material, it is not necessary to be careful with the location of the rafters. However, given the ability of the metal to sag under the weight of human weight, the sheathing beams are installed at intervals of 20 cm. This step will prevent damage to the coating, since the foot of a person climbing onto the roof for repairs or maintenance will invariably rest on the sheathing.
According to building regulations, the minimum slope of metal roof slopes is 14º, the maximum value is 30º. For flat roofs, the installation step of the slats will have to be reduced; it is even better to make a continuous covering from edged boards.
If the roof is insulated and waterproofing is laid over the sheathing, a counter-lattice made of thin slats is required to form a ventilation gap between the metal covering and the insulating layer. Thanks to ventilation, there will be an equal temperature on both sides of the roofing material, which means there will be no condensation that destroys the metal and no icicles on the eaves.
The eaves overhang is made of 3 or 4 solid boards. The ridge is formed by laying boards on both sides, converging at a single point.
Assembly of seam roof elements
Assembling a metal roof fencing begins with the installation of special crutches installed along the eaves overhang every 70 cm. Initially, two crutches are nailed along the edges, and a cord is pulled between them to align the remaining parts. The crutches can be replaced by a metal corner with a side of 4-6 cm nailed along the base of the overhang.
Attention. To cross the ridge, a 3 cm edge should be left on one side and 6 cm on the other.
- The paintings, made up of two metal strips, are transported by car lift to a storage area specially organized for them at the top.
- First of all, along the line of location of the second picture, clamps are attached with self-tapping screws every half meter. The clamp must be positioned so that its fixation point is covered by the picture laid on top.
- Then the first picture is installed, the side line of which coincides with the line of the pediment. The first element is fastened through the pediment line with self-tapping screws.
Attention. Ordinary paintings have edges of different heights, usually one is 5 cm, the second is 2.5 cm. The first strip has both edges of 2.5 cm.
All elements of a seam roof are mounted according to a similar scheme: first, clamps for the next strip, then installation of it itself and connection with the previous strip. The fold is folded together with homemade fastening strips. Thanks to the installation of clamps, simultaneous fastening is carried out both to the sheathing and to adjacent elements. Experienced roofers advise strengthening seams with silicone sealant.
Advice. To prevent unbending of homemade clamps, you can add a riveting to their location point in the horizontal seam.
- Upon completion of the merging of the seams, the joints must be sealed using a hammer and a strip of metal.
- Then the smaller edge is folded over and secured to the ridge, and the larger ridge edge is placed on top of it and secured.
If the galvanized surface is not suitable for aesthetic reasons, it can be primed with pigmented drying oil and then painted.
Lightning protection
There is an opinion that a metal roof does not need a protection device, because it is a natural lightning rod. However, a direct lightning strike can still cause a fire due to overheating of the metal installed on the wooden sheathing. If the seams between the covering elements are sufficiently reliable, lightning protection of a metal roof is carried out by connecting it through a down conductor to the grounding system. If there is an electrical connection between the covering elements, pin and torso lightning rods can be dispensed with.
The construction of a metal roof is the simplest and most economical way to arrange a country bathhouse. If all stages are carried out according to technological rules, the roof will last more than 20 years, without requiring alterations or repairs. It is important to take into account the features of the metal coating and not forget about the installation rules.
In the process of arranging roofing, various materials are used. They differ in their set of characteristics and pricing policy. One of the materials in demand today is metal. It is easy to use, practical and relatively inexpensive. Even a non-professional installer can install a coating made of this material.
To complete the finishing correctly and efficiently, you need to learn how to choose and install the right metal for the roof. Advice from experienced builders will help you understand this issue.
general characteristics
Metal has been used by humanity in construction for many centuries. Sheets of this material are subjected to special processing. The result is a finish that is strong, durable and lightweight. It is for this reason that metal is often used for roofing.
Today, sheets of this material are processed in various ways. As a result, doing metal with your own hands does not cause much difficulty. The sheets bend well. This allows them to be used on roofs of almost any shape.
Finishing can be done using metal tiles, rolled or sheet steel. The last two varieties have a lot of advantages. When using such materials, the finish is sealed. In this case, the sheets are connected in a special way. In this case, there is no need to use special materials.
Advantages
Any type of metal for roofing has a number of positive characteristics. First of all, it should be noted its durability. If treated correctly, the finish will last for several decades. It adds little weight to the building structure, unlike heavy
The cost of metal trim remains consistently reasonable. This is a universal material. It is suitable for finishing almost any type of roof. For flat, inclined, and shaped structures, metal is used. It can be installed fairly quickly.
The presented material ensures high rigidity of the joint with the sheathing. Also, metal, when properly processed, can withstand adverse weather conditions well. It has many types and design options. The roof, finished with the presented material, looks stylish and impressive.
Varieties
Covering a roof with metal is a relatively simple job. The choice of materials in this case can be anything. There are sheets of different types of metal. The customer can choose both simple and noble materials.
Finishing the roof using copper or a zinc-titanium alloy is more expensive than other varieties. Sheets made of or aluminum are also characterized by high efficiency. For such materials, a special product is used. It additionally protects the metal and also gives the surface the desired decorative effect.
Finishing the roof using tin is much cheaper. This material must have a protective layer of aluzinc or zinc. This option is most often used when arranging or outbuildings. To finish the roof of a house, it is recommended to use metals treated with a polymer substance.
Steel sheets and rolls
If it is necessary to make calculations for the roof of a dome with metal, roofs of complex configurations and other objects, consider an option such as sheet or roll materials. Their thickness can range from 0.6 to 1 mm.
Sheets are produced 1 m or 1.25 m wide and 2-3 m long. They are laid staggered. Adjacent sheets are shifted relative to the previous layer. In this case, the finish resembles an old roof. Installation is quite labor-intensive. The number of seams in this case will be significant.
Roll materials vary in width from 57 to 1 m. The length of the roll can reach 16 m. This material is used for large slopes that have a uniform slope. This material is also suitable for roofs with a steep slope. The joints in this case are connected using a special technology. In this case, installation is faster.
Corrugated sheet
The use of corrugated board is another popular material for metal roofs. Profiles in this case they belong to the load-bearing category. It has a special capillary groove. In addition to roofing, load-bearing corrugated sheeting can also be used for wall finishing.
When choosing corrugated sheeting, it is necessary to choose the correct thickness of the material. If it is insufficient, the sheet will be too soft. In this case, the groove may become deformed. And the roof will not efficiently remove excess moisture.
Several types of corrugated sheets are used to finish the roof. Grade S-21 is characterized by sufficient rigidity. It is mounted on a lathing, which has a pitch of up to 80 cm. RN-20 is characterized by large dimensions. The width of such sheets is 110 cm. This is also a fairly rigid material.
The most durable varieties are considered to be profiled sheets of categories S-44 and NS-35. They have additional ribs. The material is very durable.
Installation features
Having read the information about what are the dimensions of metal on a soft roof, hard type of finish, you should consider the installation features of the presented materials.
It should be noted that sheet and roll varieties do not have high rigidity. This is a soft type of roofing. Corrugated sheets are more rigid. However, the installation principle is similar for various metal finishes.
The elements from which the roofing covering is assembled in this case are called pictures. To connect them together, special seams are created. They are called folds. These seams create an airtight connection. They prevent moisture from getting inside. It is the folds that create a special pattern on the roof surface. Therefore, such a roof is called seam roofing.
Base for soft roof
Leaf or rolled metal for seam roofing mounted on a prepared base. If the roof is sheathed with soft material, a hard flooring is prepared. For these purposes, a continuous sheathing of boards is used. In some cases, it is allowed to use a base made of chipboard or plywood. These materials must be moisture resistant. If necessary, the base is treated with special water-repellent compounds.
Metal must not be laid on bitumen-based materials (roofing felt). There should be a small distance between the metal and the base of the roof. This allows you to create the necessary ventilation. For these purposes, a special mat made of interwoven polymer fibers is laid on the sheathing.
A membrane can be used for the same purposes. It is distinguished by the presence of truncated cones. The use of such materials not only helps to create ventilation, but also serves as sound insulation. The noise of rain and wind will be heard less.
Lathing for corrugated sheets
Hard varieties metal for seam roofing can be mounted on a slightly different type of base. In this case, continuous sheathing is used only for slopes with a small angle of inclination (up to 15º). If metal of low rigidity is to be installed, slopes are also created from continuous sheathing.
If the roof slope reaches 15-30º, you can use a board pitch of about 45 cm. This will be enough to ensure sufficient strength of the system. For steeper slopes, you can increase the pitch. The sheathing in this case can be about 60 cm. It is very important to take into account the rigidity of the corrugated board.
For brands such as NS-35, NS-60, NS-75, the angle of the roof is not of great importance. For them, you can use lathing with the widest pitch. In some cases, this figure reaches 3-4 m. This type of material is used on large objects. For private construction, less rigid materials are often used.
Connecting pictures
The presented types of finishes are connected using special seams called folds. They provide a reliable, waterproof joint. Therefore, the presented type of finishing is not needed sealants. For metal roofing the paintings are laid out perpendicular to the cornice. They are connected using double or single folds.
The height of such seams is most often about 2.5 cm. The pitch between the folds is determined by the size of the paintings. Most often it is about 50-70 cm.
The paintings are also joined horizontally. Such seams run parallel to the cornice. This installation option is suitable for long slopes that cannot be covered with one layer of metal sheets. Such joints are made using the rebated seam method. It makes the joints less noticeable.
It is extremely rare that paintings are attached using nails, self-tapping screws or self-tapping screws. In this case, the metal has to be drilled. The material cannot expand and contract freely with temperature fluctuations. It is also not a tight enough connection.
Types of rebates
Metal for seam roofingcan be connected in various ways. The seams differ in configuration. It is recommended to make standing seams double. In this case, a strong, reliable connection is obtained. Such seams are used for roofs with a slope of up to 25º. For areas with frequent heavy snowfalls, it is recommended to make a high rebate.
In some cases, if there is water on the roof for a long time, special gaskets can be used to seal the seam.
The standing seam type connects sheets of metal using special clamps. They are installed between metal paintings. With their help you can make longitudinal seams.
If the angle of inclination of the slopes exceeds 25º, you need to connect the pictures with an angular fold. Its configuration resembles the letter “G”.
Metal coating
Must be of high quality. Therefore, it is important to pay attention to its finish. Metal is most often processed with various polyurethane materials. The most popular are roofing sheets treated with polyester, pural and PVDTF.
Polyester belongs to the category of the cheapest materials. This layer looks aesthetically pleasing. However, it is inferior in strength to other varieties.
Pural is made on the basis of polyurethane. It has a higher cost. But the roof covered with the presented material is less susceptible to mechanical stress and chemicals. This is a long lasting, durable type of finish.
Polyvinyl difluoride (PVDTF) is the most durable, durable type of coating. This is the most expensive option for finishing metal sheets.
What to look for when choosing?
Metal for roofingmay differ significantly in a number of characteristics. For each type of roof it is necessary to choose the right finishing material. In this case, the slope of the slopes, the characteristics of the climatic zone, the configuration of the structure and other nuances must be taken into account.
When choosing, it is important to pay attention to the thickness of the sheets and the type of coating. Before purchasing materials, you need to make a calculation. You can order the necessary metal paintings directly from the manufacturer. In this case, their dimensions will optimally correspond to existing conditions.
You should not purchase products that are cheaper than market prices. In this case, the roof will not be strong enough. After a short time, the work will need to be redone. This will require additional costs. To avoid this, you need to purchase products from trusted manufacturers. When purchasing, you must request certificates for the metal sheets provided.
When purchasing, it is important to pay attention to a number of issues. Experts advise visually inspecting the metal. It must have sufficient thickness. Too thin varieties are not suitable for roofing. The material will be constantly exposed to various adverse influences. Therefore, its strength must be high.
You need to look at the outside. It should not have defects, rust, or peeling of the coating. It is also important to pay attention to the inside of the sheet. It should be a uniform color. There should be no streaks on the metal. The coating must be of uniform color over the entire area of the material.
Having considered the features metal for roofing, you can choose the best option for each type of structure.
To date, debates about the effectiveness of tiles and metal roofing have ended with the proof of the high protective qualities of the latter material, preventing moisture from leaking and being resistant to negative weather factors. The use of roofs made of metal sheets is observed both in the construction of housing stock and industrial real estate.
Is it possible to install a metal roof yourself? Let’s look at the main nuances of this issue.
The structure of such a roof is presented in several options:
- flat steel sheet covering, also called seam roofing;
- corrugated sheeting;
- metal tiles;
- material made of non-ferrous metal.
In order to select a coating taking into account specific requirements, it is necessary to understand the characteristics of the properties of each material available on the market. An important criterion is also the type of polymer coating, which provides reliable protection of the metal from corrosion. This coating is resistant to UV rays, temperature fluctuations and mechanical damage.
Metal roofing: features of each type
In most cases, do-it-yourself metal roofing is constructed from galvanized steel. It is fairly easy to install and is used to make downspouts, wall gutters and eaves overhangs. During the production process, the roofing steel base is treated with zinc, which prevents corrosion.
Roofing work is carried out from sheet steel from 0.5 mm, in addition, the market-proven Aluzink is used, presented in the form of a steel sheet coated with aluminum alloy, zinc and silicon - in a ratio of 55%, 16% and 1.6 %.
Corrugated sheeting is a roofing material that has been profiled, which significantly increases its hardness and elasticity. The scope of application of profiled sheets is quite extensive - industrial construction, construction of floors between floors of houses, construction of fences, cladding of premises, including utility and residential premises.
The installation of a metal seam roof is distinguished by connecting the panels with seams. This design of a metal roof assumes that the sheets that are joined together are used to create pictures; during their fastening, a seam is formed - folds.
A popular roofing covering is metal tiles, which can be seen on the roofs of retail outlets, cafes and kiosks. It is quickly installed, does not cause difficulties during transportation, is distinguished by a wide variety of color shades, a long service life, and the cost of this material is acceptable for the construction of any budget.
Using non-ferrous metal coating
Alloys of copper, aluminum, zinc and titanium are used in the production of metal roofing. Copper meets all basic construction requirements - it is resistant to corrosion, does not peel, and does not require special care, which leads to a significant reduction in operating costs. Thanks to the natural reddish tint of copper, the roof will look not only original, but also elegant. The only drawback, along with the many advantages of this coating, is the high cost.
Due to the light weight of aluminum, any type of metal roof can be constructed from it without special selection of a specific sheathing (read: ""). Aluminum metal tiles are durable, resistant to atmospheric influences, and retain their original color throughout the entire period of use.
When comparing zinc-titanium alloy and copper, the advantages of the first are obvious. The coating made of this environmentally friendly material does not rust, and its service life exceeds the service life of its analogues. Prices for zinc-titanium are 2-3 times lower than those offered for copper.
Coating installation: preparatory stage
For those who independently install a metal roof, below is an option for installing a galvanized steel structure.
Work begins with the preparatory stage, taking into account the established requirements - metal roofing snips, in which special attention is paid to:
- checking the slope angle (metal roofing made of steel sheets is constructed with a slope of 16-30 degrees);
- diagnostics of the reliability of sheathing battens;
- the quality of the roofing covering, which should not have swelling or peeling layers; The zinc layer must be applied evenly.
Additional elements when laying sheets are:
- fasteners, including nails (at least 50 mm) for attaching the roofing to the sheathing, as well as nails (100 mm) that secure hooks and crutches, as shown in the photo;
- hooks fixing gutters. To make them, you will need steel pieces measuring 420x20x5 mm;
- hooks holding eaves overhangs – 450x25x5 mm;
- clamps that fix roofing pictures on the sheathing.
Features of components when laying metal roofs
For high-quality installation, metal roofing elements must be laid according to the basic parameters. For a metal roof, sheathing and rafters are constructed, where the slats should be about 50x200 mm, and the bars should be 50x50 mm. To avoid roof deflections under the applied load, the gap between the bars is no more than 200 mm.
The eaves overhang is installed on top of boards filled with solid flooring, and its width should not exceed 0.7 m. The ridge joint is formed by two adjacent boards.
The roofing steel sheet is heavy - its weight with a thickness of 0.5 mm is 1 square meter. m. The paintings are assembled on the ground, after which they are raised to the roof.
Since all installation work is carried out at height, the technology of installing a metal roof involves the use of insurance and special belts, especially when exceeding 1.9 m.
Covering installation
Initially, crutches are laid along the eaves overhang in increments of 0.7 m, with a distance of 150 mm or more. They support paintings, which are obtained quite simply - the edges of the sheets are folded using special equipment, including folding machines. Thanks to the lying seams, fixed along the short sides of the covering, and standing seams (ridge seams), mounted along the length, the outflow of moisture from the roof surface is ensured.
For this, clamps are used, which need to be driven into the sheathing at one end, and into the standing seam at the other. The roof is made of metal sheets with a shift of the second strip of material by 60 mm to separate the lying seams in different directions. Displacement of the ridge folds is allowed at least the same distance.
The folds are connected both single and double. Particular attention is required in places where moisture accumulates, in valleys and gutters, as well as in the case of a slight roof slope. Among the various connection options, the simplest is to use a screwdriver, for the arrangement of which you only need a block and a hammer. Tools such as comb benders help increase installation productivity.
Providing lightning protection
Metal roofing, being an excellent lightning rod, does not require the installation of special equipment, however, inspection authorities may have some questions about this. To avoid controversial situations, it is recommended to combine non-metallic roofing materials with those that act as lightning rods.
What roofing material should you choose if the top priority is the complete tightness of the roof? Of course, metal roofing. This category includes corrugated sheets, metal tiles and sheet or rolled iron. Corrugated sheeting and metal tiles are installed using a fairly large number of through fasteners, which significantly reduces the tightness of the roof. But sheet and rolled iron is fastened using a seam connection, which completely eliminates through holes in the roofing material. It is the latest technology that will be discussed in this article. The installation of a metal roof has a number of undeniable advantages: complete fire safety, light weight, aesthetics and durability. And rainwater does not accumulate on a smooth metal surface. Installation of such a covering requires the use of special tools, and professional roofing crews even come to the site with their own machines, which significantly speeds up the work. But you can install a metal roof yourself; to do this, you need to familiarize yourself with the technology given below and rent some tools.
The metal roof is laid on a rafter structure with fairly frequent sheathing. The distance between adjacent sheathing strips should not exceed 25 cm. The slope of the roof slopes should be from 16 to 30 °. Metal sheets are laid on top of the sheathing, the edges of which are connected by a so-called seam connection.
A little terminology that is used when working with seam roofing:
Word " fold" migrated to us from the German language, where "falz" means "gutter" or "groove". The edges of the sheet iron are wrapped, the edge of one of them seems to wrap around the edge of the other, then the connection is sealed. The result is one of the most reliable connections that exist at the moment. By the way, if you still don’t quite understand what a rebate is, remember a tin can. The joints of a seam roof are exactly the same as the edges of a tin can - strong and completely airtight.
Paintings or cards- These are sheets of iron interconnected lengthwise. The length of the picture is equal to the length of the slope from the ridge to the overhang. For convenience and greater reliability, maps longer than 10 m are not made. Pictures can be made from pieces of sheet iron, or they can be solid, cut to the desired length from rolled metal. The last option is more preferable. Firstly, because solid paintings are more convenient to use and attach. And secondly, this increases the tightness of the roof.
It is better to do the preparation of paintings - cutting to the required size and folding the edges to create a fold - in advance, at the bottom, and lift the finished material onto the roof, which only needs to be secured. To make cards, special equipment is used - a machine that bends the edges (a machine for making self-locking folds). So all that remains at the top is to place one edge on the other and connect them together.
Kleimers to secure the metal roof to the sheathing, they are made of the same material as the paintings. This allows you to make the entire coating as durable as possible; fasteners will not fail before the roof covering and will not corrode. Clasps are a strip of metal, one edge of which is secured with a self-tapping screw to the sheathing, and the second is inserted between the edges of metal sheets and bent into a seam joint along with the edges of the paintings.
There are recumbent and standing, as well as single and double. Reclining folds used to connect metal sheets into a picture parallel to the cornice. Due to the fact that the seams are recumbent and pressed as closely as possible to the plane of the roof, water easily flows down the roof. However, recently they have been trying to make seam roofing without horizontal joints at all, in order to make it perfectly smooth. This can be done using roll technology, when a sheet of metal is cut immediately to the required length. Thanks to the smooth, level surface, not only does water drain well and snow does not linger, but the very possibility of corrosion due to stagnation of water or its entry into the seam joint is minimized.
Standing Seam Joints used in seams between metal patterns, parallel to the rafters. The standing double seam is considered the most reliable connection, providing maximum strength, durability and tightness.
Special tool for screwing seam joints. A set of two frames allows you to make a double fold in two passes. Using manual frames you can work with sheet iron with a thickness of 0.5 - 0.8 mm. The working width of each frame is 200 - 240 mm.
If roofing frames are a tool for manual work, then semi-automatic seaming machines and electric seaming machines are designed to minimize manual labor and increase productivity. They are used on large objects.
Crutches- wooden T-shaped elements, which are nailed to the eaves at the very beginning of the installation of the roofing material and are used to hold the metal sheets on the roof. Simply, they prevent the paintings from falling down.
For side, top and bottom connections of metal roofing, additional elements, such as wind strips, gutter strips, snow guards and ridge. They must be made of the same material as the roof itself.
Types of metal roofing
Seam roofing can be made of various metals, which differ in properties and performance characteristics.
Cink Steel has relatively high anti-corrosion resistance and can serve as a roof for at least 30 years (30 - 50 years). When working with this material, you must constantly ensure that you do not damage the zinc coating in any way, otherwise corrosion cannot be avoided. To extend the service life of galvanized steel, metal roofing paint is used, which is used to coat the roof every 3 to 5 years (the first time after 7 to 10 years).
Galvanized steel with polymer coating more protected from the influence of negative atmospheric factors. For example, such a coating as “pural” has already become a household name. Pural is a coating made of polyurethane and polyamide and has increased strength and resistance to ultraviolet rays. In total, there are about 17 color solutions for pural coatings, including matte ones, which give the roof a unique soft shade. In addition to pural, galvanization is coated with polyester and plastisol. With such a roof you need to be as careful as possible and try not to damage the coating during the installation process.
Aluminum somewhat more expensive than galvanized steel, but is used for roofing due to the fact that it does not corrode, does not change color over time and is very plastic. Thanks to the unique plasticity of aluminum, it is easy to cover slopes of complex shapes; the material easily bends in places where the profile breaks. The service life of an aluminum roof is about 100 - 150 years.
Copper It is considered the most durable and expensive material that can be used to cover a roof. Over time, a patina appears on the surface of copper - the result of metal oxidation, protecting the metal itself from environmental influences. The color of the patina changes over time. Therefore, a copper roof is initially fiery red, and over time acquires a matte greenish tint and even dark malachite. It is for this aesthetic property of the chameleon that copper is used to cover architectural monuments and significant buildings. The service life of a copper roof can be from 100 to 200 years, and the maximum recorded life is 700 years.
Titanium-zinc- This is a modern development, used for roofing relatively recently. Despite the fact that zinc has excellent corrosion resistance, it has the disadvantage of being brittle. This does not make it possible to use galvanized steel in complex shapes or assemblies where ductility is required. A material called titanium-zinc consists of 99.95% zinc, 0.03% copper and aluminum, and 0.02% titanium, which gives the metal strength. The service life of a titanium-zinc roof is approximately 70 - 100 years, in more aggressive conditions, for example, near water bodies - 50 - 70 years. But during the installation process with titanium-zinc you must be extremely careful: you cannot walk on it, scratch or knock on it. Also keep in mind that this material does not like the proximity of other metals and some types of wood.
To cover roofs, metal with a thickness of 0.5 - 1.5 mm is used. It is easier to work with thinner materials as they are easier to bend and fold without leaving gaps. If you plan to make additional elements from the same metal, then the recommended sheet thickness is 0.6 - 0.8 mm. More detailed requirements for various cases can be found in SNiP II-26-76. By the way, building codes do not prohibit changing the shape of the metal for the roof, for example, bending and making shaped elements. But changing the shape of the galvanized sheet is not recommended, as this may disrupt the integrity of the zinc coating.
As already written above, seam roofing is laid mainly on slopes with an angle of inclination from 16 to 30 °, but flat metal roofing is also possible. This imposes certain restrictions and slightly changes the technology of laying the material, since it is necessary to provide high-quality drainage from the entire roof area. Also, in the process of wrapping the seam joint, a sealant for metal roofing is used to maximally protect the joint from leaks.
Metal roof installation
Seam roofing is a type of covering whose installation should be entrusted to professionals. And not just roofers, but only those teams that have experience working with seam metal roofing. This is due to a lot of nuances, as well as the need for professional equipment to facilitate installation.
The modern market can offer ready-made metal sheets with folded edges of a standard length of 2.5 m or more. After purchasing, all that remains is to connect them together. But this method is not the best.
It would be much more preferable to purchase rolled galvanized steel, the same pural, for example, or copper. Directly on site, it will be necessary to cut sheets of the required length, equal to the length from the ridge to the eaves plus 50 - 100 mm, necessary for arranging folds in place of the ridge and under the eaves overhang. On a special folding machine, you can wrap the edges of the sheet to further connect them together.
Arrangement of rafters and sheathing for metal roofing
The arrangement of a rafter structure for a seam roof is no different from standard technology. It makes no sense to install rafters too often, since the roofing material is very light. But the sheathing must be done in increments of 200 - 250 mm from timber 50x50 mm or 50x100 mm. This frequency is necessary in order to minimize deformation of the roof metal during operation, installation and repair. This way, the roofer’s feet will always step on the place where the sheathing board is located under the metal, and the metal will not bend or deform.
If the roof is flat, then the sheathing must be made continuous.
The ridge is made of two boards, which meet at one point at two edges. And the cornice must be made solid, from 3 - 4 boards knocked together.
To minimize the appearance and accumulation of condensation on the back side of the roofing material, the roof must be waterproofed. If the roof has been insulated, then a sheathing is nailed to the rafters, and a waterproofing superdiffusion membrane is attached to the top of the sheathing, which does not let water in, but releases steam from inside. The waterproofing begins to be fixed from the bottom up, the joints are made with an overlap of 100 - 150 mm and are glued together with construction tape. The film should be fastened with a slight slack so that in the event of severe frosts, it does not tear due to the fact that it has narrowed and stretched between the fastenings. By the way, it can be secured with self-tapping screws and dowel nails with a wide head.
A counter-lattice is placed on top of the waterproofing membrane with the step indicated above. This will create two ventilation gaps: one between the insulation and the waterproofing, and the other between the waterproofing and the roofing metal.
Fastening a metal roof
Installation of roofing iron begins with the installation of crutches. They are nailed to the cornice in increments of 70 cm; they will hold the metal paintings so that they do not fall during the installation process. Wooden crutches can be replaced with a steel angle of 50 - 60 mm, which is attached along the eaves overhang. This method is even somewhat more convenient, since there is no need to align the crutches so that they are exactly on the same line.
Goes up first picture with finished curved edges. It is laid next to the pediment so that an overhang of 40 - 50 mm is formed. The sheet is aligned so that a 30 mm edge remains to cross the ridge (on the opposite slope the edge should be 60 mm).
Kleimers are attached on the side where the second sheet of metal will be applied. The clamp is secured to the sheathing with a 4x50 mm self-tapping screw in the place that will be covered by a sheet of metal. As a result, it should turn out like this: the curved edge of the metal should be in close proximity to the vertical edge of the clamp. All clamps are attached in increments of 500 - 600 mm.
rises second picture and is installed next to the first one so that its folded edge fits onto the folded edge of the first picture (for self-locking folds). If the edges of the paintings are smooth, not self-locking, then the edges of the first and second paintings should simply be located in close proximity, with a clamp clamped between them. Next, using roofing frames or other professional tools, a fold is made. This usually takes two passes with a hand tool, back and forth.
The clamp is also bent inside the fold, so the connection is very strong.
Important! If the house will be used in a humid climate or near bodies of water, then all connections can be additionally sealed using metal roofing sealant. This could be, for example, Tytan silicone sealant. It is most convenient to apply it to a strip of fiberglass with a width equal to the width of the folded edge, and glue this strip to the edge of the metal before making the seam joint.
Claypers are also nailed from the second edge of the second picture, then the third picture is lifted and the procedure is repeated.
In the places where the paintings adjoin the pediments, a special element is attached - side wind bar, and then the top side bar. These elements can be secured both through self-tapping screws and using seam connections (the latter is very difficult).
After all the paintings on both slopes have been laid and secured, horse, which can be ventilated or unventilated. You can see how they are performed in the photo. Also note how differently the ridge ventilation is done.
Lastly executed eaves overhangs And gutters are attached for rainwater drainage. The edge of the folded picture turns down so that water can drain easily.
Installing snow guards on a metal roof
The installation of fences and snow barriers on seam roofs is mandatory and is regulated by clause 8.11. SNiP 21-01-9. Snow guards are necessary to prevent snow from falling off the roof like an avalanche, rumbling across the roof. In addition, there is a high probability of injury to a pedestrian below. Elements of snow guards are attached to standing seams using self-tapping screws or self-tapping screws. Fences are made from profile pipes.
Due to the fact that metal roofing is conductive and attracts lightning strikes, it must be grounded and lightning protection installed. The fact is that if lightning strikes a metal roof, not only will all electrical appliances fail, but the roof itself will become hot, and the wooden sheathing underneath will overheat, which can lead to an inevitable fire.
At the highest point of the roof they fix lightning rod. It could be:
- Metal pin;
- A metal cable stretched along the ridge of the roof;
- Special lightning protection mesh.
It is best to use a metal pin with a height of 0.2 - 1.5 m, a cross-section of 100 mm2, and a diameter of 10 mm. The pin is installed vertically and must be made of corrosion-resistant metal - copper, aluminum, duralumin. Metal cannot be coated with paints and varnishes.
Down conductor used to divert lightning from the lightning rod to the grounding point. This can be a steel wire with a diameter of 6 mm, which is welded to the lightning rod and lowered down the walls. In this case, you should avoid places near windows and doors and under no circumstances bend the wire, this can lead to the appearance of a charge. The down conductor is nailed to the walls with special staples.
Grounding a metal roof can be a grounding loop made of metal pins driven into the ground to a depth of 1.5 - 2 m and interconnected into a loop. Such grounding must be located at a distance of 1 m from the house and 5 m from paths, porches and other places where people walk. The pins must have a wall thickness of at least 3 mm and be made of steel or copper. Steel bars rust quickly, so they need to be checked every 3 years and replaced as necessary. By the way, don’t forget that the wetter the soil, the better for grounding, so in too hot, dry weather it wouldn’t hurt to water the grounding loop with a hose.
Installing a metal roof only seems very simple; it is better to entrust its implementation to professionals who know all the intricacies. Indeed, in the event of a mistake on your part, if you decide to carry out the installation yourself, after a short time the roofing material may fail. Considering the low cost of roofing metal, these losses will be greater than the cost of specialist work. Don't skimp - turn to professionals.
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