Hip Roof Truss System

Hip Roof Truss System

Among the roofs for a private house, hip roofs have a good ability to clean themselves and withstand strong wind loads. In addition to excellent technical characteristics, the appearance of such structures is impeccable. However, the Hip roof truss system has a rather complex device and requires the correct calculation of all components. The presence of a competent project and painstaking installation will be the key to a beautiful and solid construction.

Hip roofs: photo of structures of interesting design

Hip roofs are a type of roof consisting of four slopes and, due to their design features, having greater resistance to strong gusts of wind. This is explained by the fact that instead of gables in houses with a hip roof, hips (inclined triangular slopes) are used, due to which the form becomes more streamlined and the roof itself is durable.

Wooden house with a four-sloped hip roof
Wooden house with a four-sloped hip roof

The absence of pediments makes the height of the house with a hip roof visually smaller, but in general, a house building with such a roof looks organic. Photos of one-story houses with a hip roof indicate that often the space directly under the roof is used to equip a cozy attic room. To illuminate the attic, the roof has full-fledged window structures.

The photo of the houses with a hip roof illustrates the neat external outlines of the roof, in which dormer windows are often equipped. This makes the roof colorful and interesting in terms of design. Four-pitched roofs are usually used for houses of large area, the base of which forms a rectangle. If the perimeter of the house has a square shape, then another type of hip roof is used – a tent.

One-story house with a tent roof
One-story house with a tent roof

The main feature of the hipped roof is that all its slopes have the same shape of an isosceles triangle and an identical angle of inclination. All faces of such a design converge at one upper point. Hipped roofs are also relevant in homes that have the correct shape of a polygon. How many sides in the polygon, so many symmetrical slopes will be on the roof. From an architectural point of view, such designs are no less attractive.

Another subspecies of the hip roof is a semi-hip roof. This combination is in the same gable and hip model design. To give the roof a streamlined shape, the pediment is covered with a small triangular slope (half-hip), the length of which is shortened along the slope. This option contributes to the fact that the ridge element of the roof becomes inaccessible to the action of wind flows. When using the space under the roof as an attic, it is possible to equip the windows in the frontal part.

Hip roofs with a bay window look exceptional. Bay windows add romance and sophistication to the whole house building. You can meet the roof with bay windows attached to the main structure or separately built over the ledge of the wall. The main disadvantage of such roofs is the difficulty in designing and quite an expensive installation.

House with a semicircular bay window
House with a semicircular bay window

Almost all modern roofing materials can be used to cover the hip structure: slate, corrugated board, metal tile, ceramic and bituminous tiles, and other materials. Roofing is selected taking into account the slope of the roof, the climate of the region, the characteristics of the material. In addition, the last role is played by the durability, aesthetics, and cost of the coating itself.

Note! The use of sheet roofing material as a tent covering will entail a fair amount of waste.

Getting acquainted with the design of the hip roof, you can find that it is quite difficult to coordinate all the slopes with the same slope. Accurate calculations, a competent design, and theoretical recommendations of professionals are needed. But, despite the complexity of the construction of the frame, hip roofs are undoubtedly popular among private developers.

Modern hip roof house
Modern hip roof house

Key benefits of a hip roof

In addition to the original design, hip roofs have a number of advantages that distinguish the design from other models:

  • the absence of pediments contributes to the invulnerability of the structure to strong wind loads. The smaller the slope of the roof slopes, the less impact wind pressure exerts on the rafter system;
  • the streamlined shape of all four slopes contributes to the stability of the structure to any type of precipitation;
  • with regard to energy-saving efficiency, this design is in many ways superior to gable roofs;
  • It is much easier to insulate the hip roof since the heat-insulating pie is located under the slopes. In models of roofs with gables – special insulation of the vertical facade is required, more susceptible to the wind;
  • the system of mowing, central and outdoor rafters provides a reliable design that is resistant to deformation under the influence of external loads;
  • depending on the slope, there is the possibility of rational use of the space under the hip roof for the attic and arrangement of windows in the roof.
Along with the special appearance, the hip roof has a high degree of reliability and strength.
Along with the special appearance, the hip roof has a high degree of reliability and strength.

The main disadvantages of four-slope models are the complexity of the device of the rafter system of the hip roof and the inability to equip the attic in models with a slight slope. However, with proper study of hip roof drawings and thoughtful construction measures, the construction of such structures becomes a feasible task.

Hip roof truss system: key elements

The hip roof frame is a ridge beam and a system of various rafters. Taking into account the fact that slopes and hips have different slopes, there are several types of rafter legs. The main components of the design include:

  • corner rafters (sloping) – the main load-bearing structural elements located at the corners of the frame. Raised rafters have a smaller slope relative to other intermediate rafters;
  • central rafters – they are attached to the ends of the ridge beam: three elements on each side. They are called central intermediate rafters;
  • intermediate rafters – are located between the central rafters, originate from the harness and end on the ridge;
  • short rafters (outdoor) – the elements are attached at one end to the rafters and the other to the harness. Truss rafters vary in length, but have the same slope;
  • ridge run – horizontally located crossbar serving as the upper support for mowing and central rafters;
  • Mauerlat – a beam fixed on top of the outer walls. It serves to evenly distribute the concentrated load of the rafter legs. Mauerlat is a kind of base of the rafter system and connects the roof frame with the walls of the house. Since the roof area is large, such a link allows the roof not to “fly away” with strong gusts of wind;

Note! Choosing the parameters of the Mauerlat, it is necessary to take into account the ability of the support beam to ensure the stability and reliability of the entire rafter structure.

  • strut – an inclined beam used as a backup for rafters of a large span, perceiving horizontal loads. Using struts, you can cover a significantly larger span and save the cross-section of the main load-bearing beams. In the construction of hip roofs, the angle of inclination of the struts is 45 or 60 degrees;
Hip roof rafters
Hip roof rafters
  • Tightening – a wooden beam that acts as additional support for the rafters and does not allow them to disperse. For tightening, usually use a beam of a smaller cross-section than for rafters;
  • Sprengel – horizontal elements laid diagonally in the corners of the walls. Sprengel acts as a support under the rack for mowing rafters. Such an element is used when it is not technically possible to install the rack on the ceiling;
  • crate – a layer of boards of small cross section, which are laid perpendicularly on top of the rafters. Acts as a base for roofing. The boards of the crate are stacked with a small step (about one board). At the locations of the valley or cornice, the crate is continuous;
  • counter-lattice – elements that are installed on top and parallel to the rafters to the battens. They are used to create a ventilation gap between the crate, waterproofing, and roofing material;
  • filly – a small section of the board with which to extend the rafter leg to create a cornice overhang. It is designed to drain rain and melt water from the walls of the house, as well as to protect the base and slopes from oblique rain.
Hip roof truss system
The hip roof truss system

In the photo of the hip roof truss system, you can see that the ridge run is located strictly in the center and parallel to the supporting walls of the house. In addition, the start and end of the run should be at the same distance from the end walls. This arrangement will ensure uniform load distribution, and, consequently, structural stability.

Hip roof truss system diagram

Hip four-pitched roofs are superior in construction complexity to conventional gable roofs. This is due to the difficulty of accurately joining all four slopes under the required slope. Such roofs have two large slopes in the shape of a trapezoid and two end slopes in the shape of a triangle. When forming the rafter system, the main difficulties arise in the construction of the hip roof.

The design of the house with a hip roof takes into account that the slope of the slopes should be in the range from 10 to 60 degrees. The choice of the angle of inclination is affected by the amount of precipitation, the material of the roofing, and also whether the under-roof space under the attic will be used. In regions with high rainfall, the slope should be at least 45 degrees.

The hip roof scheme should provide for the cross-sectional shape, dimensions, and exact location of all structural elements of the frame. In addition, the drawings of the hip roof truss system reflect the length of the ridge run, the height of the roof, the angle of inclination of the slopes, the width of the spans, methods of reinforcing the structure, and the specifics of fixing the elements.

Schematic design of a hip roof
Schematic design of a hip roof

Given that the nasal rafters have a large length and support for the growths, they need reinforcement. To do this, a sprengel is used, the beam of which is cut into the Mauerlat, and the strut leg is propped up with support. To strengthen the rafter system, the use of a wind beam is practiced. It is fixed on the inside of the central rafters diagonally mainly from the windy side of the house.

In the case when the rafters have a length of more than 4.5 m, diagonal struts are used to strengthen them, the use of which allows you to choose a smaller section for rafters. The struts abut against puffs (floor beams), which prevent the rafters from parting. If the puffs are attached closer to the ridge crossbar, they can serve as a base for the roof lining of the attic floor.

Useful advice! The closer the puff beams are attached to the ridge run, the more powerful the rafter system must be.

In the scheme of rafters of a hip roof, the feasibility of using layered or hanging rafters, as well as the use of additional reinforcing elements, is justified. If during the calculations it turns out that the beam parameters do not correspond to the required load, it is possible to use glued or stacked rafter beams. These modified elements are much more massive and can have a large length.

The roof system of the house with a hip roof
The roof system of the house with a hip roof

If house building does not have an intermediate supporting wall, then use hanging rafter legs, which rest only on two supports (on two walls of the house). In this case, the rafters experience a load on compression and bending. Due to the fact that the rafters create a bursting force on the walls, a wooden puff is used, which connects the rafters to each other. Usually, it is installed below the base of the rafter legs.

When the structure has an intermediate load-bearing wall or middle support pillars, a lay rafters scheme is used. In this embodiment, the rafters rest at one end on the outer walls, and for the middle part of the legs, the pillars are the pillars or the inner load-bearing wall. With this design, the rafters work on bending, like a beam.

Compared with the roof, where hanging rafters are used, the design with the rafters on the legs is lighter. The construction of such a roof consumes less materials, which reduces construction costs. It is possible to use a combined rafter system in one design. This happens when one part of the house has an internal load-bearing wall, and the other does not. To install a roof over such a structure, both rafters are used.

The scheme of the rafters of the hip roof with a stem is used when it is necessary to increase the cornice. In this case, the rafters will abut the floor beams. When installing a hip roof with the rafters resting on floor beams, such an element as a Mauerlat can be completely excluded from the structural scheme. Instead, it is proposed the use of wooden leveling pads.

Hip roof truss system with bay window

Quite popular in private construction is the erection of walls of houses with bay windows (ledges). This is a very interesting architectural solution, however, the designs of such houses are notable for the complexity of design and construction. The bay window can be built not only during construction but also attached to an existing building. The protrusion can be one-story and multi-story.

It is worth noting that the most difficult in the construction of houses of this architectural form is the design and installation of a hip roof with a bay window. The basic rule – the bay window roof should harmoniously support the main roof of the structure, forming a common style. It is very difficult to build a bay window, so not everyone will decide to build such a house. The slightest inaccuracy in the calculations can lead to the fact that the design will be unreliable.

The structure of the hip roof with a bay window of various shapes
The structure of the hip roof with a bay window of various shapes

The shape of the roof depends on what shape the protrusion (rounded, multifaceted, rectangular) has. This can be a hip, multi-tongue, gable structure, or a hemispherical roof. Sometimes a spire-shaped roof is erected over the bay window.

Two roof options over the bay window are practiced: an independent roof of a ledge or combined with the roof of the main structure. For the rafter system of the bay window, a material with a smaller cross section is used than for the rafter legs of the main roof structure. This is due to the fact that these elements will perceive less load.

The technology of laying the roof covering over the bay window is identical to the method of covering the main roof. It is recommended to use shingles since, for a small area with several slopes, material is needed that would leave a minimal amount of waste. This requirement meets the shingles bituminous or ceramic. To calculate the metal roof on the hip roof, you can use a special calculator.

Installation of metal
Installation of metal

Particular attention when erecting roofs with a bay window should be given to the valleys. They are used in the construction of two types – the upper-end bar and the lower. One closes unaesthetic sections, the other will drain precipitation. In addition, professionals do not advise saving on fasteners (screws, nails, studs, plates). They must be purchased in the right quantity and of good quality.

Useful advice! To increase the reliability of problem areas of the hip structure with a bay window, a sealant and sealant should be used in these places.

You can learn about the features of the construction from the video installation of a hip roof with a bay window.

Hip roof metal tile with bay window
Hip roof metal tile with bay window

DIY hip roofs: drawings and photos, sketches and design calculations

Before proceeding with the construction of a hip roof with your own hands, it is necessary to carry out the drawings and make the correct calculation of the entire structure. It would be useful to seek the help of a specialist who has experience in this field and will be able to optimally select the angle of inclination and make a calculation. Given that the roof structure may contain broken lines and irregularities, it will be difficult to accurately calculate all the constituent elements.

Tips for drawing and sketching

Before you make a hip roof with your own hands, even of the simplest design, you will need to develop a hip roof project with drawings and sketches. This will help determine the shape of the roof and make it possible to correctly calculate the required amount of materials for construction. To perform the design, you can use the following recommendations:

  • should measure the height, length, and width of the house. According to the data obtained, sketch the facade and the end face of the house on a convenient scale. Such sketches must be done in several instances;
  • when determining the optimal height of the hip roof in relation to the house and the slope of the roof slopes, it is necessary to display several options for the roof contour on one of the sketches. Next, you should choose the most successful one, and using the protractor determine the angle of inclination of the slopes of the future design;
  • the next step will be drawing on the layout marking the position of the roof rafters – in these places we mark the points. Divide the length of the wall, indicated in the diagram, into equal segments – this will be the step between the beams. It can be from 40 cm to 2 m. But it must be borne in mind that quite often installed rafter legs will entail excessive consumption of material, and a large step between the rafters will cause the use of structural reinforcement elements;
  • when determining the length of the ridge, it is necessary to take into account that the run must bind a pair of rafter legs. On one of the sketches it is necessary to note equal segments from each edge of the wall;
  • the resulting schemes are transferred to the general scheme, after which you can calculate the amount of necessary material. The length of the rafter legs is determined on the outside, based on the length of the eaves overhangs (about 50 cm).

Useful advice! In order for the roof structure to be strong and durable, it is necessary to purchase well-dried lumber.

Hip roof project, where A1 is the width of the base, A2 is the width of the foundation, B is the height of the lift, C is the length of the overhang, D is the length of the base
Hip roof project, where A1 is the width of the base, A2 is the width of the foundation, B is the height of the lift, C is the length of the overhang, D is the length of the base

By the number of rafter legs, you can calculate the number of fasteners. All nodal fasteners will use nails. For each rafter leg, there are two mounting corners. When procuring material, a small margin should be made in case of damage to the material. If the house is made of brick or blocks, you must purchase a beam for the device Mauerlat.

Slope angle selection

When determining the angle of the hip roof, the climatic conditions in which the construction is carried out should be taken into account. If the climate is hot, dry and windy – the slope should be minimal in order to prevent overheating and to avoid additional load. In areas with heavy snowfall – the slope is increased for unimpeded snow flow.

In addition, when choosing a hip roof angle, one should take into account the material of the roofing, each type of which has restrictions on the slope of the slopes:

  • Slate – the coating is used for roof slopes of 13 to 60 degrees. If the angle of inclination is less than 13 degrees, then moisture will seep into the joints, and snow will fall in winter. This will lead to a significant reduction in the life of the roof;
  • ceramic tiles – the optimal slope for this material: from 30 to 60 degrees. When laying roof tiles with a slope of less than 25 degrees, measures should be taken to improve ventilation and waterproofing;
  • metal – when laying this material, the maximum angle of inclination is not normalized, the minimum – 15 degrees;
  • shingles – the coating is used for roofs with a slope of more than 12 degrees. The maximum tilt angle indicator is unlimited. The material perfectly repeats the shape of any surface;
  • bitumen slate – sheets of this material are used with a slope of 5 degrees. There is no maximum value, however, the step of the crate will depend on the angle of inclination, and with a slope of 5 to 10 degrees, you need to equip a continuous flooring;
  • steel rebate roof – stacked at slopes of 20 degrees. There is no maximum angle limitation.

An increase in the angle of inclination contributes to an increase in the roof area, which will entail additional costs for the building material. Therefore, if it is fundamentally important to save materials, then this should be taken into account when drawing up drawings.

Features of calculating the area of ​​the hip roof

To determine the required amount of roofing material to cover the hip roof, it is necessary to calculate the surface area to be covered.

Calculation of the hip roof area of ​​a private house
Calculation of the hip roof area of ​​a private house

The following data will be required for the calculation:

  • roof dormers and chimney pipes are taken into account since their presence obliges to increase the consumption of roofing material;
  • determines the length of the slope from the bottom of the ridge to the edge of the eaves;
  • calculation of the walls of the firewall, parapets, overhangs, and other elements;
  • the calculation does not take into account the adjacency of the paintings, standing folds, protruding elements of the bars.

Useful advice! If a roll material or metal tile will be used for the coating, when determining the surface area, it is necessary to reduce the length of the roof slopes by 70 cm.

To get accurate data on the roof area, you can seek help from specialists or take advantage of modern programs that will produce the most accurate calculation. But if nevertheless, you decide to do it yourself, you need to conditionally divide the entire surface into separate elements, the area of ​​which is easy to calculate mathematically, and then add up the obtained values.

The more accurately the area is determined, the lower the likelihood of acquiring surplus material and irrational spending of finances. The amount of materials required for construction should be fixed at the design stage of a one-story house with a hip roof. The cost of these materials also includes roofing, so the cost of building a house as a whole depends on the correct calculation of the roof surface area.

Two-story house with a hip roof
Two-story house with a hip roof

To calculate the area, you must use the hip roof plan. It is also necessary to take into account the technical characteristics of the roofing (thickness, length) and the methods of its installation. The thickness of the material affects the weight of the coating and knowing the length and width of the material, you can arrange it with the least amount of waste and connecting lines.

For clarity, you can analyze the use of ceramic or flexible tiles as a roofing material. Ceramic tile is a heavy material and is 5 times more flexible in weight. Under the installation of flexible tiles, a rafter system and frequent lathing are not required, however, it is necessary to lay continuous plywood or other material under it. Therefore, in order to determine the cost of the entire construction and choose the most profitable material, it is necessary to calculate the hip roof.

The total cost of construction will undoubtedly be influenced by the area of ​​the hip roof, but it is also worth considering the complexity of erecting the structure itself, especially when it comes to arranging an attic. The complexity of the calculation will be affected by such elements as dormers, ventilation holes, chimneys, etc.

For example, you can calculate the area of ​​a four-sloped hip roof. With a roof drawing, calculations are much more convenient and the required values ​​will be more accurate. The diagrams show that the rectangle serves as the basis for the roof, two slopes are an isosceles triangle, the other two are trapezoid.

The scheme of the device of a four-sloped hip roof, where L1 is the length, L2 is the width
The scheme of the device of a four-sloped hip roof, where L1 is the length, L2 is the width

In this case, the tangent of the angle of inclination of the triangular face is equal to the ratio h (roof height) to ½ of the value b (length of the base of the triangle). So, the height of the roof is determined by the expression:

h = (b tan α) / 2.

The length of the lateral rafter leg (e) can be determined using the angle of inclination:

e = b / 2 cos α.

Using the Pythagorean Theorem, we can determine the length of the nasal rafters (d):

The total area of ​​the entire roof is calculated by summing the areas of all the constituent elements of the hip roof surface, namely four triangles and two rectangles:

S = 4(eb/2)+2(a-b)e = 2e(b+a-b) = 2ea.

If you want to calculate the area of ​​the hip roof per square house, then its value will be equal to the sum of the areas of four triangular slopes.

Hip Roof Area Calculator

Due to the fact that not everyone can independently calculate all the parameters of the roof, the websites of companies specializing in the construction of roofs and the sale of roofing materials suggest using an online calculator. With it, you can find out the exact amount of lumber, insulation and roofing materials, as well as calculate the length and cross section of the rafters for the structure of the selected type.

Using an online calculator with drawings and diagrams to calculate the hip roof, you can determine how optimal the slope of the slopes relative to a roofing is, whether the cross-section of the beam can withstand the existing wind and snow loads on the rafter system in your region.

Before calculating the hip roof using the program, it is necessary to fill in the proposed fields of the calculator: the length and width of the base, the slope of the roof, the length of the side and end overhangs, the width, thickness, and pitch of the battens, indicate the type of wood and the pitch for rafters. In addition, to calculate the load, data on the region and type of terrain are entered.

Useful advice! When working in the program, please note that in front of each filled field there is a “?” Icon. By clicking on it you can find explanations for a specific input parameter.

Hip Roof Design
Hip Roof Design

After processing the entered data by an online calculator, you will receive information about the compliance of the slope you specified with the norms of the roofing used. If a discrepancy is found, the program will offer replacement options. In addition, you will receive data on the lifting height, the length of the hip roof ridge, the weight of the roof covering, the amount of roll material, taking into account the length and width of the roll, as well as the required overlap during installation.

The conclusions of the calculator also include the roof surface area (this will include the sum of the areas of all slopes, including overhangs of the required length), the amount of roofing, and roofing material that will be required to erect the roof. The calculated value of the maximum load on the rafter system takes into account the roof structure, the weight of the roofing cake, and the entered data on snow and wind loads.

In addition, the program will calculate the rafter system of the hip roof: it will provide information on the number and size of the side and diagonal rafters, and will also offer the recommended size of the minimum section for the rafter system, the choice of which will provide the structure with the necessary strength.
Using the data of the calculator on the optimal number of rows and boards of the lathing, you can avoid possible cost overruns, as well as time costs for excessive trimming of lumber. In addition, you will receive information about the number of boards in cubic meters and kilograms.

DIY hip roofing instruction

Assembling the rafter system of a hip roof is not an easy task, but if you strictly follow the project and the practical advice of professionals, you can independently cope with the construction. The key to high-quality installation is the most correct calculation and the exact scheme, following which you can make the correct incisions of the rafter legs and install all the structural elements.

Before you make a hip roof yourself, you should familiarize yourself with useful recommendations, adhering to which you will not have to doubt the reliability of the design:

  • the intermediate rafter legs have a steeper slope than the nasal rafters. In this regard, a board with parameters of at least 5×15 cm is used for them;
  • fixation of short rafters is made not to the ridge run, but to the mowing elements. The angles of inclination of the short and intermediate rafter legs coincide;
  • lumber used for skating and rafters must have an identical cross-section. Subject to this rule of construction, proper durability will be ensured. Otherwise, the probability of deformation is high;
  • intermediate rafters are attached to the edge of the ridge beam and to the top of the harness;
  • the height of the hip roof can be any, however, if the slope is very slight, you should use additional pillars;
  • in order to extend the life of the hip structure, it is necessary to use softwood lumber, previously dried and free from defects in the form of knots and cracks. In addition, before starting work, all wooden elements are treated with antiseptic compounds.

Marking the future design

The construction of the hip roof begins with the marking of the object.

Step 1. From the side of the end of the house building, it is necessary to outline the axis along the upper wall trim.

Step 2. Next, you need to determine the half thickness of the ridge run and outline the location of the first element of the roof truss system.

Useful advice! To avoid errors when marking the object, it is recommended to use a special metering rail, on which all necessary sizes will be marked. It can be cut, for example, from a strip of plywood. Recommended rail width 5 cm.

Step 3. Attach the rail with one end to the intended line, and place the other along the side wall. So you can outline the location of the intermediate rafter legs.

Step 4. To determine the length of the rafter overhang, it is necessary to place the beam with one end at the outer corner, and the other on the roof overhang.

Step 5. To determine the location of the central rafter leg, it is necessary to move the marking rail to the edge of the side wall and fix the location of the central element of the rafter system.

This procedure should be applied to all four corners of the structure. Thus, the installation sites of the intermediate rafters and the ends of the ridge run will be outlined.

The design of the hip roof rafters
The design of the hip roof rafters

Calculation of the rafter system

After marking, it is necessary to calculate the rafter system.

Step 1. Using a rail, you must determine the horizontal projection of the intermediate rafter leg. From the table of standards, find the roof slope that is appropriate for your case and multiply the values.

Step 2. Measure the length of the rafter leg, while the measurement should be done along the bottom line from the sampling point on the ridge run to the sampling at the base of the leg.

Step 3. To determine the length of the overhang, it is necessary to multiply the value of the horizontal projection of the rafters by the correction factor from the proportions table.

Table of proportions and correction factors:

Roof slope Coefficient for corner rafters Coefficient for the intermediate rafters
 3:12  1.016  1,031
 4:12  1,027  1,054
 5 : 12  1,043  1,083
 6 : 12  1,061  1,118
 7 : 12  1,082  1,158
 8 : 12  1.106  1,202
 9 : 12  1,131  1,250
 10 : 12  1,161  1,302
 11 : 12  1,192  1,357
 12 : 12  1,225  1,414

Useful advice! In the calculations, one can use the Pythagorean Theorem, in which с² = a² + b², where a and b are the vertical and horizontal projections, respectively.

Step 4. Next, you need to calculate the angular rafters. To attach the rafter legs to the ridge beam, oblique sections are made at the ends of these elements. In turn, the ridge run also has a double bevel, so that the corner rafters are securely attached to it.

The calculation of the rafters is carried out in the following sequence:

  • from one of the angles of house-building, the length of the rafter leg is determined;
  • the projection is calculated, the value of which is equal to the sum of the squares of the projection of the central rafters;
  • the resulting number is multiplied by the correction factor from the table. This will be the length of the rafters.
Wooden system of rafters of a hip roof
Wooden system of rafters of a hip roof

Installation of rafter legs

Next, the installation of the rafter legs is performed.

Step 1. First, a ridge beam is installed, which is fixed on the supporting posts. Elements are fixed to the central beam by installing struts.

Step 2. When installing the sloping rafters, check that the length of all elements is identical. Thoroughly join the hips, sloping rafters and the ridge beam.

Step 3. After the nosed legs are installed, you should proceed with the installation of the ordinary rafter legs, which are arranged in increments of about 60 cm. The fixed rafters are fixed to the Mauerlat and the ridge by cutting. To secure the mount, use ties and crossbars.

Useful advice! When installing ordinary rafters, avoid contact with the studs that secure the Mauerlat to the ends of the walls.

Step 4. Next, short rafters (sprigs) are attached to the rafter legs. By means of outdoor elements, the roof rafters will be connected with the Mauerlat. The position of ordinary and outdoor rafters should be perpendicular to the ridge beam.

Strengthening the design of the rafters of the hip roof

There are several options for strengthening the roof structure:

  • On the corners of the structure diagonally mounted trusses with a vertical strut, which will act as an additional support for mowing rafters. The sprengel to the Mauerlat is fixed;
  • on the tightening board have racks that will be supports for intermediate rafter legs;
  • if the slant rafter leg is long, use glued or stacked beams for its manufacture.

Ventilation device

An important step in the construction of a hip roof is the ventilation device. The roof is exposed to destructive effects not only from the outside, but also from the inside, where moisture condensation can take place. This is due to the temperature difference between the outer and inner surfaces of the roof. High-quality ventilation of the roof space will preserve the roof surface for many years.

To ensure the proper level of ventilation of the space under the roof, it is necessary to arrange a hole in the wind protection film for air access. It should be located at a small distance from the ridge run. When using wood for wind filing, it is laid with a gap of up to 3 mm. In the case of using plastic material – practice perforation.

For those cases when the wind protection of the roof is mounted without a gap, it is possible to cut into it ordinary ventilation grilles with a diameter of 50 cm. They should be placed along the entire length of the wind protection at a distance of about 80 cm from each other. After completing these works, you can begin to arrange insulation, waterproofing and laying of roofing material.

The hip structure is a technically complex and painstaking process. It is worth doing the work if you have enough time, experience and knowledge in this area. Any inaccuracy can lead to unreasonable consumption of materials and higher construction costs. If you doubt your abilities, it will be appropriate to turn to real professionals for help.

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