Roofing Pie Construction for Metal Tile Roof
The duration of the operation of the roof and its reliability depend not only on the quality of the materials used, but also on the correct laying of the layers of the roofing cake. Metal tiles as a roofing material make certain requirements for this process.
Types of roofing cake
The design of the roofing cake depends on the purpose of the attic space.
A cold roof is installed if the attic space under the roof is uninhabited. Most often, this design is relevant for outbuildings or gazebos. Since insulation is not required, the design is very simple:
- metal tile;
- lathing and counter-lathing;
- rafter system.
The cold roof has a simple structure, in which the roof space is protected only by a layer of waterproofing
Although the metal tile is not a heavy material, the rafter system must withstand significant loads (snow and wind load, the mass of the roof itself and the person who performs the repair work), therefore, it is impossible to save on the quality of materials for each layer of the cake.
Features of the insulated roof
An insulated roof for metal tiles has a more complex structure, implying the arrangement of functional layers, each of which solves certain problems:
- roof covering - performs not only an aesthetic, but also a protective function, preventing the ingress of atmospheric precipitation;
- vibration insulating material - hides noise and vibration that are formed during the operation of a metal roof;
- lathing for roofing material;
- counter grill - creates a ventilation gap;
- waterproofing material - prevents the insulation from getting wet by trapping moisture that can come from outside;
- heat-insulating layer - retains heat inside the dwelling;
- rafter system;
- vapor barrier material - retains moisture that can get out of the living space;
- inner lining.
The construction of the roofing cake of the insulated roof provides for the presence of layers of vapor and waterproofing that protect the insulation on both sides
Functional layers of the roofing cake
The roofing cake has a clear structure, with each layer performing its own function. Therefore, it is by no means possible to remove any material from the structure.
Internal cladding is mainly done if an insulated roof is equipped. Most often, drywall or sheet wood material is used for it. The inner lining is attached directly to the rafter legs. After fixing, you can use any facing material, such as wallpaper or decorative plaster.
Internal cladding serves to prepare the roof surface for the installation of finishing material
Moisture can also get into the insulation from the living quarters. To prevent this process, lay a vapor barrier film or membrane. The quality of the arrangement of the vapor barrier layer largely depends on the correct fixation of the membrane on the rafters. There should be no gaps or cracks.
A vapor barrier membrane is mounted on the inside and protects the insulation from warm, wet steam from living quarters
The following vapor barrier materials can be placed under the roofing tiles.
- Polyethylene film. Can be reinforced. In addition to vapor barrier, it also has waterproofing properties. The film can be perforated and without perforation; the first option is more often used for arranging a vapor barrier. When fastening, it is recommended to use special seals that allow you to create a full-fledged vapor barrier.
For vapor barrier, polyethylene non-perforated film is usually used.
- Polypropylene film. The material is able to absorb moisture, which means that the insulation will not get wet. Requires arrangement of a ventilation gap, due to which all absorbed moisture dries out.
Polypropylene film absorbs moisture, which dries out due to air circulation in the ventilation gap
- Vapor barrier membrane. This material belongs to "breathable", its operation does not require the arrangement of a ventilation gap. The principle of operation is that moisture, penetrating into the membrane, gets stuck on its rough layer. It dries out over time.
Vapor barrier membrane does not require ventilation
Video: why you need a vapor barrier
Roof insulation is carried out only if a residential attic is arranged under the roof. When using metal tiles as a roofing material, it is recommended to choose a material as insulation that, in addition to its thermal insulation properties, could suppress noise and vibration. These are:
- mineral wool slabs (can be of different hardness);
Mineral wool slabs are able not only to retain heat in a living room, but also not to let sound inside.
- foamed insulation;
Foamed insulation does not have sufficient thickness for thermal insulation of residential premises
Ecowool is an environmentally friendly material and provides a high degree of heat and sound insulation
When choosing, it is recommended to focus on the following factors:
- thermal conductivity of material;
- its soundproofing ability;
- life time;
- fire safety.
The first parameter should be as low as possible, and the rest should be as high as possible. Mineral wool boards and glass wool are suitable for such requirements.
If a fibrous material that absorbs moisture well is used for insulation, it is recommended to make a ventilation gap between the insulation and the waterproofing, which can prevent the formation of condensation. It is easy to make it - along the edge of the rafters, at a distance of 1 cm from the waterproofing, you need to fill in galvanized nails, and pull a mesh from the cord between them.
Video: insulation test - which is better
Underlay for roofing material
A substrate for metal tiles is necessary in order to exclude contact between the roofing material and wooden structural elements. It can be either a specialized film or roofing material. The second option is used only when arranging a cold roof.
It is not recommended to lay metal tiles on a wooden crate without a backing
Waterproofing is an indispensable component of a roofing cake for metal tiles, regardless of the presence of thermal insulation material. This layer solves several tasks at once:
- protection of the rafter system from moisture;
- preventing the insulation from getting wet;
- reducing the negative impact of moisture on other elements of the roof structure.
The range of waterproofing materials is quite wide, but any of them performs the same function - it protects the insulation from getting wet from the side of the roofing
For waterproofing roofs under metal tiles, it is recommended to choose a waterproofing membrane with high performance characteristics, in particular, with the ability to prevent the formation of condensation. This material must also have other important properties:
- fire safety;
- resistant to ultraviolet radiation;
- long service life.
The waterproofing membrane is attached directly to the rafters using a construction stapler. A crate and counter-lattice are mounted on top of it.
The optimal waterproofing material for a metal roof is an anti-condensation membrane.
Video: waterproofing and vapor barrier
Lathing and counter-lathing
Metal tiles are usually laid on a sparse sheathing of bars or edged boards. The lathing serves as a kind of frame that not only holds the metal tile, but also distributes the load over the entire roof surface to the rafter system.
The optimal pitch of the lathing for metal tiles is 30-35 cm
The lathing step should not exceed 40 cm. The optimal parameter is considered to be a value of 30–35 cm. The step of the lathing may also depend on the angle of inclination of the slopes: the smaller it is, the more frequent the lathing should be.
Installation of solid lathing is also possible, but only if lightweight profiled sheets are used for the roof, the thickness of which does not exceed 0.5 mm. For such a lathing, an edged board with a thickness of 32 mm is suitable.
When using thin metal tiles, the sheathing should be solid
Counter battens are attached to the rafter legs. For fixing, you need to use galvanized nails. The fixing step is 30 cm.
Before installation, it is recommended to treat all wooden structural elements with antiseptics and fire retardants, which will help prevent rotting of the material.
Video: why do you need a counter grill
The procedure for installing a roofing cake for metal tiles
The process of arranging a roofing cake for metal tiles is as follows.
- Installation of a vapor barrier film. To do this, you can use a construction stapler or counter battens. You need to lay the material on the inside of the log. If it is necessary to arrange a ventilation gap at this stage, a counter-rail with a thickness of at least 3 cm must be mounted along the rafter joists. It is recommended to fasten it from the lower row to the upper one. Remember that the laying of the vapor barrier material should be done with an overlap of the canvases of 10-15 cm.
The vapor barrier film is installed from the inside of the room with an overlap between the canvases of 10-15 cm
- Insulation laying. The mats must be placed between the rafter legs from the outside. Make sure that no cracks or gaps form during installation.
The insulation must be laid in such a way that it does not deform and does not form gaps at the points of abutment to the rafters
- Installation of waterproofing. The work must be carried out in the direction from the bottom up, we must not forget about the overlaps. It is recommended to install the waterproofing material with a slight sag (2-3 cm) to ensure the required ventilation gap. Fastening must be carried out by fixing the counter rail along the log in the vertical direction.
The waterproofing film must be laid with a slight slack
- Installation of the crate for metal tiles. The pitch of the battens depends on the type of roofing material used. For lightweight sheets, as well as in valleys and junctions, it is recommended to mount a solid base.
- Installation of the substrate. This material should be stretched. It is recommended to use galvanized nails for fixing.
In the process of work, do not forget about safety precautions. It is better to perform work with safety belts. All fasteners and tools are best kept on a special belt or in a container. There should be no people under the roof during work, as there is a risk of serious injury.
When independently arranging a roofing pie, some mistakes are possible, especially if there was no such experience before. The most common problems that arise are:
- the absence of a counter-lattice - so there will be no ventilation gap, which means that the risk of condensation and rust on the inner surface of the metal tile will increase;
- unaligned lathing - because of this, it will not be possible to lay the metal tile in such a way that there are no cracks and gaps;
- the use of an oversized bar for arranging the crate - leads to a distortion of the metal tile, and therefore to the formation of cracks through which moisture penetrates inside;
- deformed insulation plates - the material will shrink during operation, which will lead to a decrease in its thickness and loss of thermal insulation properties;
- improper installation of waterproofing - leads to the accumulation of condensate, which is able to penetrate into the insulation.
In the absence of a ventilation gap between the waterproofing layer and the roof, condensation forms on the inner surface of the metal tile
Metal roofing operation
The roof performs a protective function, but this is possible only if it is used correctly. In particular, it is necessary to clean the roofing material from snow in time and carry out repair work. Lack of maintenance of the roof leads to its leakage. The main reasons for this problem are:
- the appearance of cracks on metal tiles in the process of natural aging - there is a certain service life of any material, including metal tiles, therefore, after its expiration, it is recommended to re-cover the roof;
- improper installation of roofing material - most often this problem occurs during the replacement of metal tiles - a leak occurs if the pitch of the sheathing does not correspond to the type of material used;
- violation of sealing at the junctions, for example, when arranging a chimney outlet. It is important to carry out repair work in a timely manner.
If small holes or cracks appear in the roofing material, they must be sealed with a sealant as soon as possible, until moisture gets into the under-roof space. If the damage is significant, it is recommended to replace the entire sheet of metal tile and, if necessary, the corresponding section of the roofing cake.
A properly designed and installed roofing cake for metal shingles is able to ensure a long service life of the roof. This requires careful adherence to the technology of laying each functional layer, as well as the use of only high-quality materials.
When choosing a heater, several factors must be taken into account. And the first of them is fire safety. Thanks to the non-combustible insulating material, it is possible not to erect heavy and expensive fire barriers, in addition, modern fused materials can be laid on such an insulation without a screed.
Compressive strength and durability are also of great importance for insulation.
For waterproofing materials, elasticity and resistance to the root systems of plants are important, which can destroy the cake of the exploited roof.
All materials must be resistant to mechanical stress, maintain performance over a wide temperature range and have durability, as well as sufficient environmental friendliness to be safe for humans.
The construction market now presents many modern and innovative materials that will help create a reliable roof - these are roll materials for hydro-vapor barrier based on bitumen, polyester and fiberglass, polymer mastics, roofing membranes, etc.
One of the well-known Russian companies in this area is Technonikol. This brand offers an extensive range of roofing materials at reasonable prices. The company has long entered the international level, and supplies goods to almost a hundred countries around the world.
Any roof includes several layers of different materials with different functions, therefore its device is called a pie, by analogy with multilayer confectionery. There are two main types of exploited roofs - traditional and inversion.
If we talk about the traditional method, then a flat roof cake will include:
- Supporting base.
- Vapor barrier layer. It is necessary in order to prevent moisture from the insulation due to steam that rises from the room.Different materials can be used as a vapor barrier - bitumen membrane, polypropylene or thick plastic film.
- Heat insulating material. The thickness of this layer must be calculated in accordance with the climate of the particular region where the roof is to be laid. Mineral wool is often used in its capacity, laying it in two layers, one of which is insulating, and the second redistributes the load. Sometimes this layer is also covered with a screed with a reinforcing mesh.
- Waterproofing. There are many modern materials for this layer, such as liquid mastics forming a rubber-like layer, roofing membranes, or fusion-bonded roofing felt.
- The final coating in the form of paving slabs is made on a concrete screed or sand backfill.
The basis of the pitched roof, its skeleton is the rafter system. It also defines the shape of the upper part of the building. Depending on the design scheme, there are single-pitched, gable, broken, hip, hipped and multi-gable roofs. The former are usually erected over annexes, verandas and outbuildings. Gable and sloping roofs, as a rule, are used in the construction of houses of unpretentious architecture, with a simple space-planning scheme.
Pitched roof rafter system
Hip, half-hip and hip (a kind of hip for square buildings) give the structure a peculiar silhouette. However, the construction of such roofs requires more complex structural solutions. The architectural expressiveness of multi-gable roofs is essentially a continuation of the general planning concept of the building. Such roofs are erected over houses of non-standard configuration, in which, in addition to the main volume, there are also peripheral branches.
The rafter system in this case is of increased complexity. For multi-gable roofs, a significant number of areas are characteristic that are critical from the point of view of ensuring the waterproofing of the roofing (valleys, abutments to brick walls, roof height differences, etc.). It is better to decide on the choice of roofing material at the design stage. This will allow you to take into account the manufacturer's recommendations on the slope of the roof, the device of interface units, the organization of under-roof ventilation, etc.
Note that the creation of a truss system for mansard roofs has its own specifics. The volume inside the wooden frame must be sufficient for the arrangement of living quarters. If the house has a sloping roof, then the problem is solved relatively easily. However, not every building is suitable for such a "headgear".
The usable area of the attic floor directly depends on the slope of the roof slopes. The height of the ceilings in residential premises should be at least 2.5 m. The area of the zones where this indicator is not maintained should not exceed the limit established by the norms. The height of the walls is also standardized. With a slope of 30 °, it should be at least 1.2 m, at 45 - 60 ° - 0.8 m. Thus, the steeper the slope of the roof, the more spacious the under-roof floor. Moreover, a slope with a slope of 60 ° will go well beyond the wall of the attic.
Construction of a mansard roof of a house
When erecting volumetric roofs, the use of wood as a structural material often does not make practical and economic sense. The construction of massive timber truss systems is a laborious and expensive process. In addition, numerous racks and other elements take up a significant part of the attic living space.
The symbiosis of wood with metal is also undesirable. Due to the high thermal conductivity, metal "inclusions" increase the fire hazard of wooden structures. In addition, abundant condensation forms on the surface of the metal during daily temperature drops, which can cause wood to rot. To exclude the contact of wood with metal elements, special types of insulation and film waterproofing are used, as well as special fire retardant paint ("Fayeflex", "Tikkurila").
Meanwhile, all these difficulties can be avoided if you take advantage of the offers of the leading manufacturers of steel roofing (Ruukki, Plannja, Lindab, Gasell Profil, Finish Profiles, Metal Profile, INSI, etc.), which supply complex metal systems, both for cold and heated mansard roofs.
Installation of a mansard roof made of metal profiles
The main bearing elements are made of a thermal profile, a special perforation of which prevents the penetration of cold and prevents large heat losses through the metal elements of the rafter system. The advent of energy-efficient steel structures has expanded the capabilities of architects. Nowadays, no one is surprised by houses with two- and even three-story attics.
The next is the thermal insulation layer. Most often, slabs made of mineral wool are used for these purposes. It is important in this case that this material is resistant to deformation. Roof insulation depends on the type of roof structure. For example, you may need to insulate the roof itself or the ceiling of the upper floor.
The insulation does not heat. Its function is to trap air in its fibers. This is called thermal insulation.
Moisture destroys insulation such as mineral wool. This is due to the fact that the coefficient of thermal conductivity of water is 20 times higher than the thermal conductivity of air. This means that the heat insulator must always be dry.
To protect glass wool and mineral wool, these materials are treated with special impregnations. However, such an event does not provide 100% protection against moisture penetration. A more reliable insulation in this regard is extruded polystyrene foam. It perfectly resists capillary and diffuse water absorption. The only drawback of the material is its high cost, in comparison with other more cost-effective thermal insulators.
Installation of thermal insulation can be carried out only when the moisture content of the wood elements of the roof is at least 18%. Otherwise, moisture from the wood will penetrate into the insulating layer, which, as mentioned above, will negatively affect the quality of the roofing cake as a whole.
What and how to attach
The metal tile is fixed with special self-tapping screws with rubber washers. As well as the main material, they are made of galvanized steel, and on top are painted to match the coating. When installing, the self-tapping screw must be screwed strictly perpendicular to the roof surface, its inclination is not allowed.
How to properly screw the screws into metal tiles
When fixing metal tiles, you must also pay attention to how tightly the fasteners adhere to the surface. It is impossible to tighten too much, bending the metal, but also a loose fit must not be allowed - the connection will not be airtight.
Roof insulation cake made of metal tiles without counter-lattice
The lathing, fixed to the frame of the truss system without counter-lattice, tightly presses the elements of the roofing pie, leaving no gaps for ventilation of the structure. In this case, only horizontal openings remain between the battens of the sheathing. This is not enough, since warm air and steam will rise, and tightly pressed structural elements will interfere with this process. As a result, all the evaporated moisture will settle on the wooden elements of the frame, and in case of damage to the vapor barrier layer - inside the insulation. This will lead to the fact that after the first winter the wood will begin to rot, and the insulation will become unusable.
The counter lattice just creates the required distance between the rafter system and the roofing pie, which allows ventilation of the entire frame. In this case, the water will not linger and settle on the structural elements, but will go outside together with the streams of warm air.
Even if all layers of the roofing cake without counter-battens are already installed on the rafter frame, the situation can be saved. To do this, to the inner side of the rafters parallel to their ribs, it is necessary to fix wooden blocks with a section of 20x40 cm.Fix the vapor barrier membrane from above with a stapler. In this case, the necessary distance for ventilation is formed between the vapor barrier and the insulation.
If there is no ventilation gap in the roofing pie, the moisture does not evaporate, but settles on wooden structures and insulation
Overlap material options
The modern building materials market provides for a huge number of options for roofing. Let's start with the most familiar and traditional ones, discuss the advantages and disadvantages, and then provide information on exotic coating options. In the end, we will draw a conclusion about the cost of material and work, summarizing all the information in a table.
Slate is a traditional, proven product that is still one of the most popular coating options. Slate is cheap, of sufficient quality and time-tested. The main disadvantage is the weight and fragility of the material, which require updating or replacing the battens.
With special care you need to approach the fastening of the slate. Firstly, the direction of laying the sheets depends on the direction of the wind. The overlap should be turned to the leeward side, otherwise the sheets may be torn out by gusty winds.
Nails are matched with a mandatory rubber pad.
The formation of cracks from a hammered nail is not allowed - after a few years the sheet will split in half Source krrot.net
Metal sheets with different colors of anti-corrosion coating. Particular attention must be paid to avoid scratches. Damage to the anti-corrosion coating will significantly reduce the service life of the material.
Any metal material is characterized by a high level of noise during rain, and therefore it is worth taking care of sound insulation.
It is a popular and easy-to-use material. A variety of palettes will decorate the most boring design. The material is laid from the bottom up. Also, do not forget about sound insulation.
Metal roofing Source makler.md
Perhaps the easiest material to install, under which, nevertheless, a solid lathing and good waterproofing are required. When calculating the budget, these factors should be taken into account. The material has only one drawback: it can be laid only at positive temperatures.
Roofing from soft tiles Source remdim.info
Clay tiles are fragile and heavy, but durable material. Such a coating is used longer than slate, but it is rather difficult to install it, and therefore expensive. Is it worth it - everyone decides for himself.
Clay tile roof Source dom-expert.by
Cost of work
Let's calculate the approximate cost of roof covering works. Our calculation will include materials, alteration of the lathing, hydro and vapor barrier, roof insulation and installation of the coating, as well as the installation of a ridge. The calculation will be carried out at average prices for a square house with dimensions of 10x10 meters. The gable roof of such a house will have an area of one slope of 60 square meters, respectively, the total area of coverage is 120 squares at an angle of inclination of 35 degrees.
The first step is dismantling of the old coating and lathing. Average price tag in Russia: 250 rubles. per square. This means that for our standard house it will cost 30 thousand rubles.
The next step is installation of insulation plates... The cost of the material is on average 2,000 rubles per square meter, plus installation will cost 100 rubles per square meter. It turns out 252 thousand rubles
Installation of waterproofing... The price of the material is on average 150 rubles per square, plus the work will cost 80 rubles. Total 27600
Counter-lathing will cost about the same price as the crate. Those. 30 thousand rubles.
Counter-lathing Source legkovmeste.ru
Metal tile will cost 400 rubles per square meter, plus 300 rubles. worth blocking sq.m. roofs. This means that the installation will cost 84,000.
Skate installation... The average cost of a 2-meter section of a ridge for a metal tile is 450 rubles. Installation will cost about 150 rubles per running meter. Total: 3750
In total, it turned out 427 thousand. But you need to take into account unforeseen expenses, and therefore we will round the amount received to 450 thousand rubles. It goes without saying that this is a very average value, it all depends on the cost of building materials and construction work in a particular region. But in any case, such a calculation can show you how much money it will take to cover the roof of a private house.
Here is a small table of coating materials with average prices for the fall of 2018.
Material cost per sq. M.
In the calculations, it is also necessary to take into account the costs of the crate, which may differ depending on the method of sheathing, the costs of repairing the rafter system and repairing the ventilation shaft and risers.
In the calculations, you need to take into account the costs of the crate. Source goldkryshi.ru
A private house with a flat roof is an original element of the countryside landscape. Its roofing is designed for a variety of needs, which affects the method of making coatings - roofing pies. They usually include concrete slabs or metal profiles, vapor barrier, waterproofing and insulation (1 or 2 layers). In the case of breathable, green, membrane, inverted and exploited roofs, a different approach and materials are required, including: technoelast, uniflex, special double-sided tape, PVC and EPDM membranes and mineral wool
Particular attention is paid to the drainage system, because comfort, structural reliability and the service life of the roof itself depend on it. The ideal ready-made option is a two-story house, however, as an alternative, they offer a one-story version or a house with a garage.