There are now more than a dozen architectural options for arranging roofs-however, there are not so many truly popular among them. The so -called hut roof also belongs to them, which, thanks to a number of features, has extremely high resistance to winds. Structurally, this type of roofs is closest to four -sloping roofs on the rafters, but is somewhat more complicated. Nevertheless, with the exact step -by -step compliance of the technology, a certain supply of patience and the presence of all the necessary materials, an independent construction of such a roof is quite possible.
From the traditional 4-pitched roof, the hollow is fundamentally different, first of all, the shape of the slopes. Two of them are long, geometrically in the shape of an elongated trapezoid. The second group consists of short, made in the form of inclined triangles above the ends of the building (it is they that are called the «Walm», dating back to the same old German term). The main difficulties of creating such a design are an accurate docking of the corners of all slopes, as well as in organizing a unique rafter frame. The rafter system of the hip roof (the diagram of which is shown in the photo) contains 3 different groups of rafters:
central (or, otherwise, ordinary);
diagonal (or taccous);
and corner (external).
For this reason, if the hollow roof is built with your own hands is built, the drawings of all its components should be absolutely accurate. In addition, when they are compiled, it will be necessary to take into account:
the materials from which the frame and roof will be assembled;
average annual and maximum wind speed in a given area;
The intensity of atmospheric precipitation.
All three of the above points affect the choice of calculating the permissible angles of the slope of the slopes (and, therefore, on the final height of the roof — in turn, leading to a decrease or increase in the number of all required building materials).
It is obvious that even if a firm decision is made, to cope with the construction of a hip roof yourself, to make algebraic calculations according to complex geometric schemes, to put it mildly, it is difficult. And, if only you do not have serious experience in special computer programs designed to build drawings and calculation of materials on them, it is this part — theoretical — preparing for the construction of a holm roof is best entrusted to professionals.
Fastening of structural elements
As noted earlier, holly roofs, the design of which is a special case of all 4 pitched roofs in general, has two fundamental features. The first of them is a pair of short triangular slopes (due to the small area of effectively opposing even the strongest winds). The second-a complex, 3-view system of rafters associated with a similar form of slopes. Having detailed drawings in hand, a marginal rail and remembering the school theorem of Pythagoras (necessary for calculating the lengths of the hypotenes in rectangular triangles), the entire structure can be assembled not so quickly, but, nevertheless, completely independently. True, not forgetting about the five important rules:
1. The first of them is the understanding of the fact that the angle of inclination of the intermediate rafters is always sharper than the rafters of the corner (which is the need to use thicker boards for them — usually a bar with dimensions of at least 15×5 cm).
2. Short elements are attached not to the central board of the «skate», but to corner rafters.
3. Materials used for assembly both the frame and the skate system should be identical.
4. Central (or intermediate, ordinary rafters) for a pair of long slopes are fixed to the edges of the «skate».
5. At the same time, similar rafters of holly slopes rest against the end of the skateboard and the upper end of the strapping.
Varieties of holly roofs
Given that all varieties containing short triangular slopes are attributed to hip roofs, they can be divided (as the complexity of the design increases) into 3 main classes.
Sharp
The simplest subspecies in which the roof is formed by a docking at the same corners of 4 completely identical in shape and area of triangular. It is obvious that it is advisable to cover the house with a similar roof only with a square section.
Semi-valm
The hip roof of this type is the only one where the triangular ramp covers the pediment not entirely, but only partially, starting from above.
Broken
The most difficult, but incredibly beautiful, presentable type type of holly roofs. The slopes in it are all different, and they join at different angles. Building such a miracle of architectural art is a difficult process, but the result is worth!
Roof markup procedure
The initial stage of the construction of the holly roof is the exact marking of the location of all its components. This must be done because the hollow roof, the rafter system, the calculation of the lengths of each beam and the places of their attachment with any error can lead to a violation of the stability of the entire system due to the formation of weaknesses. In general terms, the location scheme will be as follows:
The central (and at the same time carrier) axis of the entire structure will be a powerful skate beam;
From it, like the ribs from the ridge, a group of tattoo rafters will diverge (with the thickness of each rafter equal to the ridge beam, and with a length that allows you to remove the second end of the board 50-70 cm further than the supporting walls);
In the same way, the central group of ordinary rafters is located, which are taken to the walls and attached to the ends of the skate;
The boards of the intermediate frame will pass along ordinary slopes (there is no need to fix them for holm);
Finally, there are different rafters of different lengths, as mentioned above, the only ones do not attach to the ridge beam — but the angle of their fastening is the same.
The mutual location of all groups of rafters is determined as follows:
The edge of the skate against the end wall is taken as the basis, from where — along the upper strapping — and the marking of this main beam begins to be made;
The location of the intermediate rafters is verified using a measured rail — one end of which is applied to the line noting the median axis of the skate, and the second to a similar line on the surface of the side wall;
The distance between the outer angle of the wall and the overhang of the roof will be equal to the length of the overhang of the rafters;
The place for each subsequent beam of the central rafters is determined by transferring the measuring rail to the side wall (more precisely — its edge) and an alternate mark of the points of the future contact with it, which fall between the side wall and the upper strapping;
Completely similarly the same process is repeated at the remaining 3 corners-as a result of which we will get the exact location of all the ends (both the skating beam and intermediate rafters).
Measured rake and its use
In fact, this tool is a thin board, plywood sheet or plastic strip of about 5-centimeter width. To accelerate the work and the absence of the need for the constant use of roulette, all the necessary marks are applied to the surface of the rails (at the distances required by the drawing of the roof with already calculated linear and angular parameters). Errors in the location of the elements of rafter frames with this approach are excluded — subject to the use of a table, in which for any angle, the correspondence of the length of the inclined beam of its horizontal and vertical projections is indicated.
Examples of calculations
Correction coefficients in the table will give the exact possibility of marking the rafters than for a smaller step in the angle change in it will be indicated. Or, if there is a desire to do without a table and take a calculator with you, any length of the hypotenuse — which will be an inclined board — can be calculated according to the Pythagorean theorem from the length of the projection, which in this case is a chapel. In other words, from the formula A2 + B2 = C2 (where the horizontal and vertical projection is the letters A and B) you can get the value from. So, for a horizontal projection of 3 meters (the distance from the edge of the wall to the central line under the ridge beam) and the height to the skate of 4 meters we get the length of the inclined rafter of 5 meters — since 42 + 32 = 52. In the same way, you can calculate the projections themselves — or take ready -made data from the table.
Installation of rafter systems — important comments
Speaking about the skating beam, as the basis and the central axis of the entire system, we did not mention vertical racks — which will support it. Reliable fastening of the first to the second is achieved at the expense of the system of bias, which will be the first stage of installation.
The second step (according to the above scheme), the installation of the rafters is carried out. Their length should be the same, in contrast to roofing ions (cutting with different lengths from 50 to 70 cm). At the same time, the accurate combustion of a rolled triangle, skate and diagonal rafters is especially important.
The diagonal is the installation of the rafters of the central, the step between which is on average about 60 cm. Next comes the queue of the central frame, the bars of which are cut into the skate beam and Mauerlat. Additionally, fixation is provided with screeds and crossbars, and the Mauerlat itself is attached with hairpins.
The ligament between the Mauerlat and the frame of the same rafters is carried out with the help of people, fixed on both sides to the diagonal strips. At the same time, the installation of people, like ordinary rafters, is carried out relative to the ridge timber at an angle of 90 °.
Video and photo of rafter systems in our article.
Methods of strengthening the hip roof
With large enough, the hut roof can be reinforced — and with several different methods. The most popular among them can be called the use of sprenigs, racks or double beams.
In the first case, the supporting diagonal rafters of the stand with sprenigs (representing the bars, which are thrown between the angle of the same and second shoulders of the Mauerlat), is installed at the corners of the roof.
In the second case — if there is a concrete overlap or screed — they are fixed on them, the propagating the middle of the rack frame, thus playing the role of peculiar “shelves”.
In the third case, instead of one beam, they simply use their double pair (this method is effective if the length of the clay rafters is especially large).
The price of such a design will not exceed the cost of more traditional types of 4-pitched roofs-and after creating the crate and insulation of the roof, the process of construction ends.
Arrangement of ventilation on a hip roof
In addition to insulation, any (including a valme) roof will need ventilation. It is easy to equip it — it is enough only in one way or another to provide air circulation under the roof. He can enter through a windbreaker, and go out — in the upper part of the roof, not far from the skate.
If the ventilation system is thought out in advance, it will be enough to just leave a small, literally a couple of millimeters in the bearing of the boards for this. When using plastic — select perforated sheets. If you forgot about ventilation during assembly, the best option would be to insert several ventilation grilles. Their choice in the market is quite large — both in size, and in form, and in color solutions. The most convenient for fake roofs will be small, 5-centimeter grilles with a grid located in a step of 0.7-0.8 meters along the wind.