- Installation of waterproofing film
- Lathing and final surface preparation
- Laying tiles
- The final stage
Firstly, in terms of all kinds of colors and shapes, it occupies a leading position among all types of coating. Today, each brand of shingles is represented by at least 40-50 types of different options, so even the most fastidious buyer can always find the option he likes. Secondly, in terms of convenience and speed of installation, this is also the most successful, from a technological point of view, coating option that does not require the use of special equipment and tools. Due to its low weight, lifting and delivery work directly to the job site is simplified. Thirdly, having the properties of elasticity and flexibility, this type of coating can be used on any type and shape of the roof, even those with a radial curvature. The last advantage inherent only to this type of coating is that with the advent of bituminous shingles, it became possible to implement projects of some forms of roofing that had previously been impossible to perform technologically. The affordable cost of such material should also be noted..
Before laying the shingles, it is necessary to perform a number of activities that are associated with the arrangement of the “roofing pie”. In this article I will consider all the stages of work related to the installation of bituminous tiles that must be performed after the completion of the installation of the rafter system.
Installation of waterproofing film
The first stage of work is associated with the installation of waterproofing (windproof) film. In this case, it is possible to use a diffusion membrane-membrane, since the roofing of shingles does not contain elements that are subject to corrosion. In this regard, there is no need to apply additional measures to exclude this type of impact on the material. This class of insulation is quite widely represented on the market, but the most optimal and often used in construction is the waterproof film of the Czech company “Juta”, which is called Jutafoll 110-D. When buying, pay attention to the marking “D”, since this letter means that the film is waterproofing, and not, for example, is intended for use in the range of negative temperatures, unlike other markings that are intended for use only indoors. The number 110 is not so important, since it indicates the density of the film. If this parameter is higher, then this will affect the technical characteristics only on the positive side..
The installation of the membrane is quite simple. The first roll of film is rolled along the eaves across the rafters and nailed to them with pre-prepared slats. It is convenient to shoot the film with a staple gun before this. The slats will be a counter lattice and will serve as a ventilation gap between the waterproofing film and the main lathing. These measures are taken to organize the circulation of the air flow, and thereby exclude the collection of moisture in hard-to-reach places. Also, given the fact that air has good thermal insulation properties, these measures are designed to solve the problem of heating in summer and freezing of the roof in winter (the formation of ice and icicles is excluded). The height of the slats is chosen in the range of 25-50 mm, the width should be strictly equal to the width of the rafter leg. They are cut to length by 150 cm, like the width of the film.
The rail does not achieve the film overlap distance (at any membrane joints, an overlap of at least 12 cm is made). In all cases, galvanized brushed nails are used for installation, the length of which is selected depending on the thickness of the counter-lattice (the length must be at least + 50mm of its thickness). On all roof ridges, the film is not brought 5-10 cm to its end due to the fact that the air movement under the roofing begins from the eaves and ends in the ridge, therefore such a gap is made for its exit. The film can be glued between each other with double-sided adhesive tape, but this is an optional condition.
Lathing and final surface preparation
Next, the final crate is stuffed on top of the counter-lattice. Any board (both edged and unedged) is suitable as a material, the thickness of which is selected in the range of 25-30 mm. Before installation, the material must be dry (with a relative humidity of no more than 20%) and must be treated with a fire-bioprotective agent. Also, when using unedged boards, it is necessary to completely remove the bark of the tree, since in the future this is fraught with the fact that woodworms can start between the bark and the wood. The distance between adjacent boards should be no more than 30-35 cm (depending on the thickness of the board used). The length of the nail is chosen such that, when nailing, it breaks through both the crate and the counter-lattice and fits tightly into the rafter by at least 2-3 cm.
The peculiarity of shingles, as a covering, is that the plane of the roof before laying it must be smooth and even. Therefore, if an edged board is used as a flooring (this option is allowed by the manufacturer), then the differences between adjacent boards are not allowed more than 2mm. This must be monitored to exclude fractures and bends of the tiles during installation..
It is better to start installing OSB boards on the roof with the hip.
I recommend using OSB-3 moisture resistant board as a flooring. The thickness is usually chosen 10-11mm. Unlike a board, when using it, an ideal plane is obtained, also, having moisture-resistant properties, it does not warp or warp throughout its entire service life. When laying, it is necessary to make gaps of 3-5 mm between each sheet of plates to prevent them from swelling at the joints, since the linear dimensions of the material will change with fluctuations in humidity and temperatures. For nailing the plates, galvanized nails 3×30 with a large head are used. The nailing pitch between nails is 25-30 cm.
Then go directly to the installation of shingles. First, fiberglass backing carpets are rolled out. They are an additional waterproofing material between OSB-3 board and bituminous shingles. If the angle of inclination of the roof is less than 18 degrees, then underlayment must be installed over the entire roof surface. But even at large angles of inclination, carpets must be laid in the following places:
- On the cornices. This is one of the most important places, especially in winter, since when the snow melts, ice and icicles are formed in these places, and in this case, the load in the parts of the roof under consideration increases.
- On the pediments. Such places are most susceptible to moisture ingress during slanting rain..
- On skates and ribs.
- In valleys (joints of roof planes). Here it is necessary to use carpets with color tinting of the main roof covering.
- In places of various joints and abutments of walls, chimneys and other.
In valleys, the carpet is laid with an overlap of 0.5 meters.
The indentation from the edge of the eaves should be about 1-2 cm, as in hot weather it is possible to heat and straighten the underlayment. It is necessary to nail them only in the upper parts at a distance of 20-25 cm, and all joints should be made with an overlap of about 10 cm. Then stainless steel cornice and pediment strips are mounted. To do this, you need to use the same 3×30 galvanized nails with a large head. The strips are nailed in a checkerboard pattern with a step of 15-20 cm.In the joints, a mandatory overlap of 15 cm is made, fixed with two nails.
After that, proceed to laying the first row of tiles. According to the standards, it has a rectangular shape (without petals). Previously, all places of contact of metal strips with bituminous tiles must be coated with bitumen mastic. The mastic has a rather thick consistency at room temperatures, therefore, to simplify the work with it, it is necessary to preheat the container with the product. It is applied to the tile surface using a narrow construction trowel. The thickness of the applied layer does not exceed 1-2 mm, since it does not contain an adhesive base, and with thick seams, the lubricated surfaces can simply disperse. One shingle shingle is nailed with four nails at the top. If the angle of inclination of the roof is more than 60 degrees, then two more nails must be used..
The second and subsequent rows of tiles are nailed with an offset of half a period (1/3 or 2/3, depending on the chosen shape of the tile itself). Every 3-4 rows must be checked for horizontalness, or you must first mark the upcoming row (for this purpose, a thread with colored talcum powder is ideal), but this is a rather painstaking work that takes a lot of time. The shingles have to be cut to fit. For this, it is better to use a short knife with a sharpened blade at the end. It is necessary to cut off the back side of the tiles, placing a piece of flat board or plywood, to prevent accidental damage to the previously laid tiles. The mark is carried out with a knife about 3-4 times, then the shingle is bent along the cut line, and the tile is easily divided into two parts.
To work on roofs with a slope of more than 30 degrees, a number of additional measures should be taken to increase the convenience of work. The first thing to use when working is a safety rope or rope. The second is the use of temporary slats, which are nailed to the slope, bending the petals of the already laid tiles. Otherwise, during installation, you will have to constantly keep the rope in a taut state, since it will not be possible to resist on such slopes on your own. And thirdly, the use of overalls (construction overalls) for the competent and functional distribution of the necessary tool in pockets and loops for quick access.
In the places of the edges and ridge, the installation of the tiles is performed with an overlap (the sheet girder is bent by 10-15 cm to another roof plane and nailed down). Then the tiles are cut into separate petals and mounted on top along the line of the ridge (rib), moreover, each subsequent petal is nailed in such a way that the places of the nail heads are covered from the previous tile element.
There are several basic methods for installing roof tiles in valleys. The first is that the elements of the tiles are stacked end-to-end on both planes of the roof. The second – involves laying the tiles, not reaching 10 cm to the center line. The latter method is preferable both from an aesthetic and practical point of view, since a kind of hollow is formed between two roof slopes, which simplifies the flow of rainwater, and, thereby, prevents the formation of local areas in which moisture can collect in the future. In valleys, the use of nails closer than 30 cm from its center is not allowed, for this contact between the lining carpet and the tiles are coated with mastic to a width of 10-15 cm.The upper parts of the petals of each row are carefully trimmed at an angle of 60 degrees.
The final stage
At the junction of walls and chimneys, the tiles are placed on a vertical plane to a height of 20-30 cm, after having coated the joints with bitumen mastic. Then, in the place where the tile ends, an abutment bar is installed on top of it, and all the gaps formed are passed through with a heat-resistant silicone sealant. It is advisable to install metal boxes around chimneys and pipes, using basalt-based insulation as an insulator. They significantly improve the hydrophobic properties at the joints, preventing complex roof sections from all kinds of leaks..
Aerators are necessary for air circulation in the interroof space.
At a maximum distance of 50-60 cm from the roof ridge, it is necessary to install aerators, which serve to remove air from the space between the roofs and, thereby, allow to organize competent air circulation. The number of aerators is chosen from the following calculation: one aerator for every 25 square meters of the roof. Nowadays, ridge aerators have also become widely used, which are an air-gap structure installed directly in the area of the entire length of the ridge. All joints and overlaps around the aerators should be treated with mastic..
It is worth noting that all installation work on the tiles must be carried out at an ambient temperature of at least 15 degrees, at lower temperatures, you should use a building hairdryer, heating the tiles in places of bends. On too sunny and hot days, you need to postpone the installation of the roof, not only for the safety of your own health, but also due to the fact that the tiles begin to melt easily, and when moving along the coating, traces and dents remain that do not look aesthetically pleasing in the future.