There are several types of roofs, they differ in shape and number of slopes. In this article, we will take a closer look at one of the varieties - a four-pitched roof, find out what the truss system of a four-pitched roof is and what are the features of its installation.
Types of pitched roofs and truss systems
The roof of the hip type is a structure formed from four elements. Two of its slopes are in the form of trapezoids, and the other two are triangles.
There are no gables in the roof, which makes it more economical than a gable roof. Attic viewing windows are located in this case directly in the slopes. Triangular-shaped elements are called hips.
There is also a tent type hipped roof. In this case, unlike the hip type, all four slopes are in the form of triangles converging at one point. Hip roofs also do not have gables, so they are economical to install.
However, the arrangement of a hipped roof is such that it requires the installation of a rather complex truss system and careful fitting of the roof. As for the principle of fastening the rafters, they distinguish between hanging and layered methods.
The hanging type system is quite complicated both in manufacturing and in repair work. They make such a structure based on external walls and use it if there are no internal load-bearing walls.
The layered rafter system is a simpler and cheaper option. It is customary to install it on a house with intermediate column-type supports, which are located on a concrete floor, and an average load-bearing wall.
When installing an additional support, the length of the span covered by the rafters increases. It is advisable to make the system with a hipped roof slope of up to 40 °.
Hip roof truss construction
In roof truss systems of various types, quite a lot of differences and features can be observed. The standard construction of a hipped roof is such that there must be slanting rafters directed to the corners of the house.
Rafter rafters are often called diagonal rafters. Usually they are made of double boards or timber, since they bear the main load. Diagonal rafters have the longest length compared to the rest, so they are often made in two parts.
Note! In this case, it is recommended to support the joint of the two elements with a stand-support for increased reliability. It is desirable to place the support at a distance of one fourth of the length of the diagonal rafter from the ridge element.
It is important to note another important feature of the rafter system for hip roofs - the need for additional rafters that are shorter than usual.
Narozhniki - this is the name of these corner rafters, resting with their upper ends on the diagonal ones. To evenly distribute the load on the rafters, the rafters are mounted in such a way that they are connected to them in different places.
With a diagonal rafter length of more than 7 meters, it is advisable to install an additional rack under the bottom of the rafter. With the other end of it, it is possible to lean on the floor beam, if the beam is of sufficient thickness, or on the sprengel - a beam laid in the corner of the building on adjacent walls.
The rack may be installed on the ceiling if it is made of reinforced concrete, but waterproofing and wood gaskets should be taken into account. To strengthen the truss, you can use struts, then you get a truss truss.
If you caught the eye of a four-pitched roof scheme, you can clearly see that the rafters can be attached to the ridge in three ways.
- When performing one ridge run, the rafters can be joined by making a double cut at a right angle, then attaching them to the running consoles.
- If the design is made with two runs, then a sprengel is mounted on their console along with a stand, in this case it will serve as the basis for a reliable stop of the diagonal rafters made of their boards.
- The rafters are not made of boards, but made of timber, rest on a thick short board nailed to the main rafters of the slopes, which have a trapezoidal shape. In case your hip roof has a variety called Danish, the surf from the short board is made longer and attached much lower than the ridge. Diagonal rafters are attached at the junctions of the side rafters with the surf. In this option, the front slopes are trapezoidal, like the side ones, and at the top it is possible to make attic windows.
Roof options such as four-pitched hip roof, is considered one of the most popular, as it is not only aesthetically attractive, but also reliable and durable. Therefore, this type of roofing can most often be found on country houses, summer cottages and cottages.
Hip roof truss system
Hip roofs are no less popular due to their simplicity and reliability. If you have to carry out the installation of this type of gable roof truss system, then some differences from the installation of a hip structure should be taken into account.
At do-it-yourself hipped roofs there is no ridge run, this is their main difference from others.Four main diagonal (sloping) rafters are firmly connected at one, the highest point of the structure.
A big plus if it is possible to install another rack in the center that supports the rafters connected together. Then the structure will gain additional strength.
Note! If it is not possible to install the rack for various reasons, you will have to assemble the truss system from suspended rafters. But in this case, additional modules will have to be introduced - racks, puffs and other elements that strengthen the structure.
The main, central rafters are installed from the top of the system to the walls, strictly at a right angle. Parallel to the main rafters, the sprigs are mounted, reinforcing the diagonal rafters in advance with the help of a cranial beam.
If the beam is not used, the sprigs can be cut into the diagonal rafters, or cut under the plane of the rafters and nailed.
These methods are applicable to the installation of roofs of private houses, but are unacceptable for large buildings, due to insufficient structural strength for heavy coatings.
Ceilings made of reinforced concrete make it possible to place a bed under the main and additional racks, which is placed on a double waterproofing layer. Waterproofing will prevent rotting of the wooden structure.
Sloping rafters of great length should be further strengthened by installing trussed trusses at the corners of the structure. They are arranged according to the same principle as when installing a hip roof. Sprengels will greatly strengthen the structure and extend its service life.
Rafter system of a gable broken roof
The simplest roof, used in construction almost everywhere, can be considered a gable roof.Consisting of two slopes located obliquely, it is found on small country houses, country cottages, baths, utility rooms.
The most simple and very reliable, it allows you to use any roofing material, and even a homeowner inexperienced in construction matters can install it.
Broken type of roof - the design is already more complex, requiring more careful attention during installation. Therefore, the truss system of a broken gable roof needs more careful calculations.
Usually this type of roof is used if they want to use the attic as a useful living space. The design consists of two broken slopes, sloping at the top, from the ridge, and steep after the bend.
Although this form is quite original and attractive in many respects, the installation of truss systems is complicated and requires a large number of reinforcing modules.
However, for those who want not only to make the house beautiful, but also to use the maximum area for living, this option can be called acceptable.
Note! Thus, if you are planning to make a simple gable roof, then you will be able to cope with the installation of the truss system yourself. It is better to carry out the construction of a sloping roof with the help of specialists. Or, at least, make a preliminary drawing and calculations of the future design, after consulting with professionals.
General rules and recommendations
With self-production and installation of a truss system, such a roof as hip hipped roofit is important to follow some rules. By following them, you will successfully carry out construction work.
- Decide which type of system suits you best.
- Make, if possible, a drawing of the future roof.
- Decide what should be the angle of a gable roof or the slope of a multi-pitched one.
- Choose the type of truss system. If you have a small house, you can perform a hanging type of system. If the building is large enough and there is a central, one or more load-bearing walls, a layered system is needed.
- Calculate the footage of the required material, as well as the thickness of the boards and timber that will be used to make the rafters. Remember - in this case it is impossible to save on material. Insufficiently strong rafters simply will not withstand the weight of the future roof.
- Get all the necessary tools in advance, as well as nails, screws, etc.
- The main part of the roof structure is easier to assemble on the ground. Mount everything you can at the bottom, then lift the structure, and continue mounting already on the roof.
- Securely fasten all structural elements to each other, checking the strength and accuracy of the fasteners in the process.
- Follow safety precautions, because you will have to work at a fairly high altitude. Therefore, it is advisable to insure yourself with a strong belt or cable attached to the roof.
You can summarize by recommending that you at least minimally study the information about what types of gable roofs exist, as well as more complex options. By reviewing them, you will not only have an idea about the types and varieties of roofs. It will be much easier for you to make the final, optimal decision for you.
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