Since ancient times, people tried to protect themselves and their loved ones from external aggressive factors, whether it be cold or heat, rain or snow, wild animals or harmful neighbors. So it's no surprise that over the millennia, countless materials have been used as protective barriers and ceilings - from stone, clay and straw to wrought iron gratings, concrete blocks and roofing profiled decking.
Brief description of the main types of roofing
Let's briefly compare the most common materials used today for these purposes. As before, cement-based slate remains the “leader of rental” for us, more often - wave, less often - flat. This is an excellent budget option, proven over decades - both for arranging a roof and for installing a fence (quite fragile, darkens over time, does not allow bends and is terribly banal).
Ceramic tiles are stylish, durable, as they say, for centuries (high price, increased load on the truss system due to the large weight, requiresprofessional editing).
Euroruberoid - inexpensive, easy to install, reliable (not stylish, not durable, high requirements for the quality of the surface to be coated, most often used for industrial floors).
Flexible bituminous tiles - excellent appearance, durability, arbitrary roof geometry, ideal for roofing (high material price, qualified installation, strict requirements for the base surface).
Metal tile is aesthetic, lightweight, easy to install, available in a wide range of colors, with proper installation retains its characteristics for decades (noisy during rain and hail, additional measures are needed to protect against wind pressure, there is a high probability of damage with concentrated load).
Another widely used roofing material is corrugated board. This is the "brother" of metal tiles, which has the same advantages, but is less demanding on wind protection, more resistant to bursting, has a lower price, and in addition, is an excellent material for creating a fence.
There is still a mass of specialized and universal materials for the formation of fencing and roofing, which are able to satisfy the most demanding requests, but if we talk about the balance of price and quality, then, undoubtedly, various types of roofing corrugated board are among the leaders.
Profile - general description
Let's take a closer look at the main characteristics and applicationsprofiled sheet as an element that plays a key role in the proper functioning of the roofing system as a whole. It is advisable to use roofing corrugated board for the roof at an angle of inclination of the slope to the horizon of at least 8 °. Structurally, the material is a hot-zinc (strip) metal sheet, as a rule, with a polymer coating applied to it, having a given corrugation geometry and a capillary groove that prevents moisture from accumulating at the junctions of the profiled sheet locks. Depending on the requirements for the quality of the overlapped surface and the expected snow load, the thickness of the roofing corrugated board can vary from 0.3 to 1.5 mm, and the profile height - from 8 to 114 mm. Sheet rolling is carried out on specialized equipment, while, according to the specifications, it is possible to manufacture corrugations of various geometric shapes.
Deciphering the marking of the profiled sheet
The dimensions of corrugated roofing are standardized and are reflected in its marking. The first is a letter designation that characterizes the scope of the profiled sheet.
- C - wall, used for wall cladding and fencing (fences).
- H - load-bearing, used for arranging roofing, withstands human weight and snow pressure without deformation, if necessary, it can be reinforced with stiffeners.
- HC - professional sheet of mixed purpose.
The numbers following the letters inform about the wave height in millimeters, and then are presentedsheet thickness data.
The two final sets of numbers give information about the size of the corrugated roofing sheet, its installation width and the possible maximum length.
Thus, knowing the marking, it will not be difficult to determine the main parameters of the profiled sheet. For example, marking HC35-0, 5-1000-6000 will mean that we have a universal (roofing and wall) corrugated board with a wave height of 35 mm, half a millimeter thick, an assembly width of 1 m, with a possible maximum sheet length of 6 m.
Profile parameters MP 20
The most common size is MP 20 corrugated roofing, which is due to the combination of an ideal compromise between weight, load-bearing capacity, aesthetic appearance and its price.
Profile of this type has a trapezoidal profile and is produced in three versions - A, B and R, where the first two modifications are used as a fence, and modification R is designed to protect the roof. Type A has a predefined front (resin coated) side, while option B has a painted surface (or even both) to be specified by the customer. The base of the trapezoid profile of the MP 20 corrugated roofing sheet is wider than the top, which provides additional resistance to static loads. For wall modifications, an inverse proportion is used, which is more effective in terms of resisting dynamic wind pressure.
Geometric dimensions
The size of corrugated roofing is one of the key parameters,determining the need for the amount of material for the planned work. It should be understood that it is economically feasible for manufacturers to use one sheet size (as a rule, this is galvanized rolled steel with a width of 1250 mm), and the width of the finished profiled sheet at the exit will depend only on the depth of the wave. Because the higher the height of the corrugation, the smaller the sheet size will be, respectively. For example, for the C8 brand, it is 1200 mm, and for the C75 of the same material, the width will be 800 mm. Modern rolling mills are able to produce roofing sheeting up to 14 m long, however, the most optimal size for transportation is 6 m, and it is much more difficult to mount sheets of longer length, and if we talk about building a fence, it is also pointless. Therefore, profiled sheets are usually cut into strips two, two and a half or three meters long.
Features of calculating the need for sheets
If the task is to cover a flat pitched roof or mount a fence, then the calculation of the need for profiled sheets is calculated by simply dividing the total overlapping surface by the usable area of roofing corrugated board, rounded up. This parameter differs from the pure geometric dimensions of the sheet and is calculated by multiplying the installation width of the sheet (taking into account the horizontal overlap) by its length (for the roof - taking into account the vertical overlap). In this case, the smaller the slope of the slope, the greater the overlap should be. If the angle is less than 14 degrees, then two corrugations with a vertical overlap of at least 200 mm are allowed on the horizontal overlap, with a largerthe steepness of the roof, the lock can be one wave with the top sheet entering the bottom one by 100–150 mm.
Formation of the cornice and front overhang
In addition, the overlapping sheet should slightly extend beyond the overlapped surface, forming a kind of visor, called the cornice and frontal overhangs. This is done to protect the walls of the building from the effects of precipitation. The size of the overhang depends on the type of corrugated board, the type of wind protection (wind board or plank) and the subsequent use of the gutter to drain water from the roof surface. For a thin sheet with a small corrugation depth, this size is from 50 to 100 mm, and for materials with a large cross section and profile height, an overhang of up to 200–300 mm is allowed.
In order to accurately calculate the need for the amount of galvanized roofing corrugated board, a drawing of the future roof is drawn and sheets of an accessible size are schematically placed on it, taking into account roof windows, ventilation pipes and other protruding elements. Here we apply the general approach, which implies the purchase of material 10-15% more than the calculated one. This is done for insurance purposes when work may be stalled due to a lack of one or two sheets damaged during installation, a possible marriage in the material, or another force majeure situation.
Calculation of the weight load of roofing
Another basic characteristic that affects the design of the roof of the building as a whole is the weight of the roofing corrugated board (specified by the seller), where the measure is one square or running metermaterial. It depends on the thickness, width and specific density of the galvanized sheet, as well as the height of the corrugation. For the most popular MP 20 brand, the mass of 1 m2 is 3.87 kg for a sheet thickness of 0.4 mm and 7.3 kg for 0.8 mm. Thick-walled, high-profile grades can weigh up to fifteen and a half kilograms per square meter.
Protective functions of the roof
Playing the role of a protective barrier, the roof is designed to counteract a number of aggressive factors resulting from negative impacts both outside and inside the premises.
The mechanical characteristics of the profiled sheet should provide the required protection of the roof from the load caused by exposure to precipitation, primarily compensating for the pressure of the snow cover.
The polymer protective layer, in addition to the aesthetic component, is designed to protect the sheet from corrosion processes provoked by chemically active particles in the air, levels temperature drops, and also resists solar radiation activity.
Reliable fastening of corrugated board to the crate solves the issue of wind pressure.
Waterproof requirements
From the bottom of the profiled sheet, it is necessary to provide a hydro-barrier that protects the wooden base of the roof from mold, and the insulation from getting wet, due to condensation or moisture leaking at the joints. During installation, it is important to provide for natural ventilation, which allows for high-quality removal of moisture. Wind thrust is created by means of inextricable airchannels formed from the eaves (low pressure zone) to the ridge (high pressure zone).
Procedure for mounting profiled sheet
Roofing corrugated board is mounted in rows, taking into account the wind rose, from the lowest point of the slope (taking into account the cornice and frontal overhang) upwards, overlapping with adjacent sheets, both horizontally and vertically. At small roof slopes (less than 12°), it is recommended to seal the joints with silicone glue to avoid leaks.
The profiled sheet is fixed to the crate of a wooden beam with a step depending on the height of the profile and the slope of the roof slope. If the angle is more than 15°, then the step should be 35-50 cm, and with a smaller slope and a corrugation depth of less than 20 mm, the crate should be solid.
Methods of fastening corrugated board
Fastening corrugated board is possible with self-tapping screws or even simple nails, but the possibility of corrosion and roof leakage is not ruled out. Therefore, it is more expedient to use special self-tapping screws designed for fixing profile sheets and metal tiles to the base. They are equipped with an ethylene-propylene rubber gasket, which provides reliable sealing of the mounting hole from the self-tapping screw, without interfering with its main task - reliable fixation of the roofing. The length of the fastener is selected based on the thickness of the sheet, the height of the washer-gasket and must ensure reliable fastening of the corrugated board to the crate. In addition, the screw heads can have the same color coating as thefastened material, thereby not spoiling the appearance of the roof. At the end, they have the shape of a drill, they easily penetrate through the thin metal of the profiled sheet.
To avoid the appearance of cracks, they must be screwed in strictly perpendicular to the base, avoiding distortions along the lower (adjacent to the crate) surface of the wave.
Additional elements for mounting profiled sheet
When forming a ridge and in case of corrugated sheet adjoining vertical surfaces, external and internal corner strips (shelf width 150-200 mm) are used based on the same material and coating as the profiled sheet, mounting them with an overlap of 100-150 mm.
Properly installed corrugated roofing is able to provide comfort and beauty to your home for many years.
