Hip roof rafter system. Do-it-yourself hip roof - rafter system device

Before construction, many owners of plots think about how to build housing, a summer house or another object that is not only functional, but also aesthetically beautiful. The hip roof is suitable for creating a residential or non-residential attic and adding beauty to the object. This article describes how to make a system of rafters, take into account all the nuances in the calculations and install without errors.

The hip roof rafter system is complex, but when it is ready, the result is worth it.

Features and design of the hip roof varieties of hip roofs

The hip roof, most often, consists of four slopes. They line up at an angle along the outer walls of the building. Two parts are lateral, like standard roofs, and the remaining two are installed between them. In this design, there are two vertices (instead of the standard one) that the ridge connects.

Vertical slopes, in shape - triangles, and are called hips. The other two pediments, installed along the longer sides of the object, are trapezoid in shape.

The hip roof has characteristic features:

high strength indicators;

durability;

thanks to the original and streamlined shape, wind protection is obtained.

Such a roof is ideal for organizing living space in the attic part of the house. Make skylights on it easier.

Hip roofs are not one template for everyone - an individual project is selected for each house

Dutch hip roof

When the length of the hip is less than other side slopes, such a model is called Dutch (or half-hip). This form withstands strong gusts of wind and does not accumulate snowfall.

The Dutch hip roof is suitable for areas with a harsh climate

Danish roofing

It differs in that here the half-hip is the lower part of the triangle of a full-fledged hip, and the upper part of the triangle is used under glass.

At the top of the hip leave a small gap for the window

Hipped hip roof

Such a model has one vertex that connects four equal parts of the roof. Outwardly, in its form, the tented version is similar to a pyramid.

In a hipped roof type - all four triangles depart from one vertex point

broken roofs

It is not recommended to calculate and install such spectacular and difficult to create a roof yourself (without professional training). They consist of a large number of slopes, which are placed at different angles of inclination.

Video description

The device of a complex hip roof on an aerated concrete house is shown in the video:

Hip roof: device, nodes and reinforcement of the hip roof

The hip roof device basically consists of two elements: a rafter frame and a Mauerlat. The logs connected into a single system are attached to the mauerlat installed on top of the outer walls of the building.

Location of the Mauerlat for the hip roof

The design of the hip roof consists of the following elements:

Corner rafters. These are standard power "legs" that connect the corners of the building with the ridge beam. Most often, projects use four beams, the same thickness as the ridge. They are attached to it with one edge, and the opposite one is displayed outside the walls of the building.

Skate. This is the main bearing axis and the highest point of the roof, where all its sides are connected. Usually the center of the ridge, there is also the center of the entire roof in the hip project.

short rafters. These logs or wooden beams are attached to the Mauerlat on one side and the other to the corner rafters. Their number depends on the area of ​​the roof.

Ordinary frame. These are 6 rafters occupying a central and intermediate location. They are attached to the ends of the ridge beam and placed on the load-bearing walls of the facility. They line up on all sides of the building in a frame number.

intermediate frame. These rafters are fixed from the ridge beam and placed on the Mauerlat. The hips are not involved.

A classic example of a hip roof device and a drawing with explanations:

Gain

For long-term use, not only a strong system of rafters is required, but also additional elements of strengthening the object.

For the reliability of the roof structure, it is required to strengthen it with additional elements.

For greater reliability, you need:

Place the sprengel-beam on the corners, between the sides of the Mauerlat. This will reinforce the rafters diagonally.

Add a rack connected by a beam. Such a support for the rafters will help redistribute the load on the structure.

Use boards or timber with a section of 40 * 40 or 50 * 50 mm for the crate.

Work with dry wood treated with a protective solution.

When the sprengel is added at a considerable distance from the corner, an additional farm is organized.

Knots

Schematic representation of the nodes of the truss system

On our website you can get acquainted with the most - from the construction companies presented at the exhibition of houses "Low-Rise Country".

The angle of the roof slope hip roof area

The approval of the angle of inclination of the slopes is the optimal solution between the reliability of the roof from winds and snow and the usable attic area. How to calculate the usable area of ​​a hip roof is indicated in the picture.

Calculation of the angle of inclination of the roof slopes

The angle of inclination depends on the area in which the house is being built and the climatic conditions of the region. The principle is simple: colder weather - higher angle of inclination. So the snow will naturally roll off the roof. In warm, non-windy areas, it is better to make a small angle.

Another factor in choosing the angle of inclination is the material of the hip roof. Recommended values:

Ondulin - at least 5 °.

Soft tiles - from 15 °.

Slate - 16°-65°.

Metal tile - from 13 °. The maximum angle has not been established.

Metal seam roof - more than 25 °.

Ceramic tiles - 35°-65°.

Creating a large angle makes it possible to build a roof from corrugated board. In this case, the height of the profile itself should be taken into account. The angle is created within 20° - 45°.

Video description

In the video, we offer to see how the hip roof is covered with corrugated board:

First you need to determine the end axis of the building

When designing a roof, two rules must be considered:

A larger angle of inclination of the roof makes the entire truss system heavier and more complicated, and increases the load from the winds on the slopes. For a non-residential attic, the angle often varies from 25° to 35°, and for residential - from 35° to 55°, and reinforcement of the rafter structure is required.

The weight of the attic should not exceed the load indicators of the foundation and walls of the house. Violation of this rule leads to deformation of the base and distortion or destruction of the building.

Important! the ratio of the height of the roof to the length of the bearing walls cannot be more than 2/3. So, if the width of the house is 9 m, and the base and the 1st floor are 4 m high, then the height of the attic “for housing” is not more than 3 m, and the height of the ridge beam is less than 6 m.

Rafters are fastened with metal plates

Formulas

The area of ​​a hip roof is defined as the sum of two hips and its side slopes. The hip area is obtained by the formula of a standard isosceles triangle: S = 0.5 * a * h, where a is the base of the hip, h is the height of the hip plane.

The area of ​​the side parts is found by the trapezoid formula: S = h * (a + b) / 2, where a is the length, b is the base, h is the height. The area of ​​the trapezoidal parts is obtained from the area of ​​one rectangle and two triangles.

The area is calculated based on the length of the eaves, and not the edge of the building.

Advice! The area of ​​roofing building material is usually larger than that for a roof. This is due to the specifics of the “overlapping” covering of the material. Therefore, to calculate the material for the roof, it is recommended to add + 10%. When the design of the hip roof is complicated, then + 15-20%.

Hip roof - rafter system device

To calculate the system of hip roof rafters, it is necessary, using a standard rail, to determine the horizontal projection (laying) of the intermediate rafter leg.

To find the length of the rafter, you can also resort to the Pythagorean theorem

To find the length of the corner rafters, you need to multiply the laying by the coefficient from the table above

On our website you can find contacts of construction companies that offer the service. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

Video description

In the video, an example of the design calculation:

To determine the cross-section of a tree for legs from rafters, you can use the table below.

So, with a distributed load on the legs of 125 kg / m and a span of 6 m, a beam with a cross section of one of: 240 * 80 is selected; 230*90 and 220*100, or round timber 220 mm.

An example of a drawing of a hip roof truss system:

For an unprepared person, the drawing is quite complicated

Hip roof truss system, scheme 2:

At first glance, the schemes do not differ, but each has its own characteristics.

Video description

In this video, useful information on the hip roof truss system

Stages of work on the installation of a hip roof

The quality of the entire roof, its reliability and service life depend on the stage of installation of the truss system. It is important to approach this issue with knowledge of the matter or to involve specialists.

Mauerlat installation

For installation, they take a first-class tree with an impressive section of 100 * 100 or 100 * 150. The beam is laid only in an overlap, not in a joint. There should also be connection points with the walls of the house in large numbers. The joints are reinforced with metal staples.

In buildings made of bricks, foam blocks and wood concrete, an armored belt is additionally constructed under the Mauerlat. Studs are sewn into such a belt in advance for the subsequent covering of the tree.

Create a run

This part in the form of a beam is created for attaching additional supports for the rafter legs. The run is not the main element of the system; it is implemented in large and complicated projects of hip roofs.

Support legs

These racks are a support for the skate.

Racks are an indispensable part of the truss system

Creation of a skate

All beams rest on this element of the hip roof truss system. It is located in the highest central part of the roof. It is formed as a result of the connection of the rafter pairs of legs. A very large load acts on this section of the frame, therefore, in order for the ridge beam to withstand it, several options for joining wood are used: end-to-end, overlap and half-tree cut.

Methods for connecting rafter beams

Installation of rafter legs

The rafters can be mounted in the following order: first diagonally, and then the rest, or first the central beams, and then the diagonal ones. At this stage of installation work, the rafter legs are installed on the Mauerlat. There are several mounting methods.

Mounting to the Mauerlat can also be different

The scheme of fastening the rafters to the Mauerlat and to the ridge run

Important: the service life and reliability of the entire truss system depends on the installation of the legs to the Mauerlat. So, if you install the fasteners weakly or by making a mistake, the roof can simply be “demolished” by the wind completely.

Video description

In the video, the process of marking the rafters:

Fastening of layered rafters

There are two schemes for attaching layered rafters:

…and “hard top – loose bottom”

In order to create a warm attic, installation should be carried out according to the following plan in the figure.

For a warm roof, its own roof arrangement scheme is used

The specifics of the device during installation

The hip roof truss system requires the use of special tools for its construction.

Special tools are required to securely fasten the rafters.

For reliable construction from a bar and a strong abutment of the rafters, metal tools are used. Their types and names are shown in the figure.

Video description

Methods for attaching rafters to maurlat, installation, cuts, knots and installation to a roof truss in the following video:

Additional elements for a hip roof are also presented in the assortment. They are used during finishing work and are used to create an aesthetic appearance. They also meet the requirements for reliable construction of roofs and junctions.

Additional elements for a hip roof

Hip roof options

To create spectacular architectural solutions and expand the internal usable space of the attic, the designers have developed several options for arranging hip objects.

Roof with bay windows

Part of the house in the form of a protrusion beyond the boundaries of the facade is a bay window. Such an element is built in the form of a polyhedron or rectangle and added to the overall system of rafters. The space he created is suitable for extending the living room, hallway or use as a flight of stairs.

Hip roof for a house with a visor

The project is shaped like gable tongs. The visor has a different angle of inclination than the triangular slopes of the main roof. Often designed when the building does not have a residential attic. Sometimes used as a canopy.

Project of a four-pitched roof with a visor

Roof with cuckoo

Outwardly, such a design is a tong with an underestimated part. The element performs the function of supplying additional natural light to the living area. It can be built at the same distance from the side walls of the house and above the entrance. It is also an additional decoration of the building.

Asymmetry

Roof design with different angles of inclination is mainly used not to create living space. It is installed in areas with strong winds. The asymmetrically positioned slopes and canopy act as wind load distributing elements and prevent the object from falling off.

Roof with irregular diagonal

Complex projects with different in shape and length of the side parts of the roof form a diagonal displacement of the rafter group. Such solutions are usually used over a garage or bathhouse.

Complex roof projects with irregular diagonals

Outcome

The hip roof adorns almost any building. There are many types and methods of arranging the truss system that makes it up. With proper calculation and installation, such a roof lasts for centuries. It is possible to apply it for the house, arbors, baths and other objects.

The hip roof is characterized by a large number of advantageous moments, among which are attractive geometry, uniform heating and protection of the structure from precipitation. Even strong gusts of wind do not affect such a structure, since it does not have gables. If we compare it with a gable roof, it can be noted that the probability of deformation of the hip roof is much less. It is possible to list the advantages of such a roof for a very long time, but we must not forget that the hip roof truss system is a rather complex structure. This fact can be a significant reason when choosing the type of roof. Despite this, private developers very often build a hip structure, due to its similarity to a four-pitched frame.

Some features of the hip roof

When comparing a hip and gable roof, you can immediately notice that there are no vertical gable walls in the hip roof device. They are replaced by triangular slopes located at the ends. Due to this, the visual and real volume of the roof is significantly reduced. From the economic point of view, the benefit of this is a moot point, since when cutting large sheets of roofing material into hips, there is an increase in costs.

Like any structure, the hip roof is conditionally divided into simple geometric shapes. The simplest option has symmetrical slopes: two in the form of a trapezoid and two in the form of a triangle. That is, the whole structure consists of four slopes, which served as the basis for the parallel name - a four-sided roof.

The side section of the hip roof resembles a conventional gable roof in the shape of a triangle. When visually inspected in profile, you can see a trapezoid, which is conditionally divided into a rectangle with unfolded triangles adjoining on the sides. The shape of the trapezoid is determined directly by the developer and depends on the ratio of the length of the ridge to the length of the cornice overhang. The part of the structure, which has the shape of a rectangle, is built on the basis of roofing standards for the construction of hanging and layered truss systems.

The hips that replace the gables must be installed with a certain slope, since the design provides for their connection with the inclined sides of the trapezoid. It is the device of the hips that is the most difficult stage in the arrangement of the hip truss system. For those who decide to do the work by analogy with the usual pitched method, we can say that nothing will come of it. The thing is that the length of the ridge run does not correspond to the length of the slope, therefore, the rafter legs of the hips in the upper part, as well as the triangular parts of the large slopes adjacent to them, remain without support.

As a support, the design provides for the installation of special rafter legs that connect the ridge beam and the corners of the structure. A look at the hip roof from above allows you to notice that the sloping elements are diagonals, for this reason their second name is diagonal. In addition, the design of the hip roof implies that the diagonal will become a support for rafters of different lengths, which are installed at right angles to the overhang. These different-sized elements are called spawners.

Thus, the main elements of the hip truss system are:

• Ordinary hip roof rafters, the lower part of which rests on floor beams or Mauerlat. Depending on the type of support, the rafters can be hanging or layered.
• Diagonal rafter legs, necessary to connect the corners of the roof and the edge of the ridge beam. Such elements can be used both for the convex corners of the hip structure, and for the arrangement of the concave corners of the valleys.
• Sprockets - elements that create the plane of the hip and parts of trapezoidal slopes that are adjacent to the diagonal rafters.

Description of diagonal rafters

Given the location of the diagonal rafters, it can be determined that their length will be greater than the similar parameter of ordinary rafters. In addition, being a support for the spooks, they take on a rather large load. All this leads to the conclusion that the diagonal rafter legs should become reinforced. Most often, boards designed for ordinary rafters, but paired with each other, are used for this.

Paired braids allow you to solve three problems at the same time:

• Increasing the load without the risk of deformation of the truss system.
• Obtaining a solid diagonal element (building rafters leads to a weakening of individual sections).
• Reducing the cost of installing a truss system (two boards will cost much less than a solid beam).

The significant length of the diagonal rafters requires the installation of additional supports, the number of which is determined by the length of the diagonal.

Supports for diagonal elements

The design of the hip rafter system, regardless of size, requires the presence of supports that reinforce the diagonal rafter legs. With a sloping length of more than 9 meters, the installation of at least two supports is required. Spans of shorter length can be supported by one support located in the upper part.

The diagonal rafter legs can be supported by:

• Vertical posts installed directly on the ceiling. If the ceiling is reinforced concrete, then a piece of waterproofing material must be placed under the rack.
• The struts, which rest against the bed with their lower part and are located at an angle of 45 degrees, and the magnitude of the angle of inclination does not play a special role.
• Sprengels, which are made in the form of the letter "T" inverted. This element is used when the diagonal needs two or more supports (read also: ""). When installing, it is important to ensure that the base of the sprengel is perpendicular to the slope. In most cases, such supports are placed closer to the corner of the roof, that is, at the bottom of the rafters.

Additional supports are best made from twin boards and installed in places where the greatest load is expected.

The design of the reference points of the slopes of the rafters

The upper part of the slanting rafter leg rests against the ridge beam. The design features of the hip roof allow you to do this in several ways:

• If the roof structure has one ridge run, then the slope rests on the ridge console.
• If the rafter system has two ridge runs and ordinary rafters made of boards, then the slopes should rest on the truss, the base of which lies on the ridge runs.
• If the design provides for the presence of two runs, and the rafters are made of timber, then a surf is used instead of a sprengel. This element is made from cutting boards with a thickness of more than 5 cm and connects ordinary rafters to each other not far from the ridge.

Depending on the method of planting, the upper part of the braid is cut. You can fasten the diagonals with nails, while reinforcement with a twist of wire or a metal clamp is allowed.

In the lower part, the diagonal rafters of the hip roof supported by the Mauerlat are fastened with metal brackets or corners directly to the Mauerlat or to a specially installed corner beam.

The device of the conjurers

By means of the spears, hips and triangular parts of large slopes are formed. In the upper part, the element rests on a diagonal rafter, at the bottom - on a Mauerlat or floor beams.

The guards are installed in two ways:

• With the help of a notch. In the diagonal rafters, nests are cut down at a distance of 20 cm from each other, while it should be remembered that the cutting of the sprigs of adjacent slopes should not be performed opposite each other.
• Installation of cranial bars, which will act as supports for the sprigs. To do this, take the bars 5 * 5 cm and chop them on the lower part of the braid. This option is considered more efficient, since cutting can weaken the strength and stability of the slat. In addition, the use of this method allows you to place the sprigs opposite each other.

The fastening of the sprigs in the lower part is carried out by analogy with the installation of ordinary rafter legs.

Installation of a simple hip rafter system

The easiest way to build a hip roof is to buy a finished truss system and install it. But building a hip truss system with your own hands will bring more pleasure and allow you to create a structure that matches the entire structure. To make sure of your own strength, you can practice on small buildings, for example, build a hipped roof over a gazebo or summer kitchen.

The creation of the simplest hip roof takes place in several stages.

Stage 1. Creation of a roof model and drafting.

The construction of any structure is preceded by the design stage. This helps to determine the shape of the structure and acquire the right amount of material. A simple hip roof does not require a complex drawing; it is enough to draw by hand an approximate diagram of the hip roof rafters.

To draw up the simplest hip roof project, it is enough to follow the steps described in the following instructions:

• The parameters of the structure are determined, according to which an approximate drawing of the roof is drawn up in profile and full face. In order for the drawing to correspond to real parameters, it is necessary to select a scale, most often 1:25 is chosen. This means that the size should actually be divided by 25.
• The roof contour drawing helps to choose the optimal roof height, and in several versions. The most suitable pattern measures the angle of inclination of the slopes.
• Further in the figure, the points of installation of the layered rafter legs are marked, while each side must be divided into equal sections. The pitch of the hip roof rafters should be optimal so as not to increase the consumption of building material, but also not to reinforce the structure with an additional counter-lattice.
• The next step is to determine the length of the skate. It should be remembered that this part of the structure must connect a whole number of roof trusses. On both sides of the long side, you need to set aside the same segments.
• Based on the figure, the required amount of material is calculated.

The number of fasteners is determined by the number of rafter legs, taking into account all nodal fasteners. For each rafter, you need to purchase two corners. Boards are best bought with a small margin so that you can eliminate random errors in construction. If the structure is being erected on a concrete or brick box, then care should be taken to purchase a beam from which the Mauerlat for the hip roof will be constructed.

Stage 2. Installation of the main part.

Installation of the hip truss system begins with the installation of the ridge part:

• Directly in the middle of the walls, to which the hips will adjoin, one board is nailed. A construction cord is pulled between them, which must pass strictly along the central axis.
• Two rafters are applied from one of the ends of the structure, their intersection should pass under the cord. The cut line of the upper heel of the rafter leg is marked, taking into account the ridge run about 5 cm thick. The necessary part of the element is cut down so that the envelope roof is of the required shape.
• According to the workpiece made, the rest of the rafters are sawn. It should be remembered that when erecting a hip roof with hanging rafters, the length of the cornice overhang is taken into account.
• Farms are assembled from two rafter legs and fastened to one nail.
• A ridge beam is installed through all the farms and rafters are nailed to it.
• In the lower part, the layered rafters are attached to the Mauerlat, the hanging rafters of the hip roof are attached to the floor beams. In both cases, fastening is performed using metal corners.
• Previously nailed auxiliary boards can be removed, as they are no longer needed.

Stage 3. Construction of hip slopes.

The rafters of the hip part are attached by analogy with ordinary rafter legs: the top is fixed with nails, the bottom - by means of corners to the Mauerlat or the upper log.

The installation is carried out as follows:

• Expose the first diagonal rafter and put a mark at the place of the saw cut. In this case, the lower part of the element should be located in the corner of the roof.
• Saw off the element along the intended line and fix it: top - with nails, bottom - with corners.
• The remaining diagonal rafters are installed in a similar way.
• To fill the hip slope, the sprigs are tried on and installed individually.
• After that, they proceed to the installation of the sprigs of the main slopes.

After installing all the elements of the truss system, the following is done: using a wire twist, every second rafter is tied to a log of the second row or to wooden plugs that were previously laid in the walls. In addition, stranded wire can be embedded in masonry or between blocks during wall construction. It should be remembered that from the top to the location of the twist should be at least three rows of bricks or two rows of blocks.

The finished truss system is closed with a crate. If the coating is soft, then the crate should be solid boards, plywood or OSB boards. Rigid roofing materials can be laid on a crate made of a bar nailed with a certain step.

Construction of a complex hip roof

The frame of a complex hip roof is being built in a similar sequence, but with minor modifications. For example, diagonal rafters should be fixed in a more durable way, with the installation of additional supports. The ridge part is installed after the installation of the support frame, which includes the bed at the bottom and the ridge run at the top.

It is much more difficult to build a hip roof truss system than a conventional gable roof structure. However, a hipped roof looks more attractive both over a house and over a light building.

Having tested your strength in the construction of a hip roof over a gazebo or other household building, you can achieve a good result in the independent construction of a four-pitched roof over a residential building.

A hip roof is one of the types of a four-pitched roof, its design includes two main trapezoidal and two end triangular slopes, forming a closed surface with a common ridge run. If the side slopes are located over the entire area from the ridge to the cornice, then the roof is called hip, and if they do not reach the eaves, it is half-hip.

Types of roof structures for a hip roof

If the truss structure rests only on the main walls of the building, it is called hanging, and if it has additional support points due to the walls inside the house, then it is called layered.

If the truss system relies only on the external load-bearing walls of the building, it is called hanging

If the building has two main walls, then a tension beam is laid in the upper part of the vertical posts, which reinforces the rafters and distributes the load over the entire area of ​​the vertical support posts.

To create a hip roof, a layered rafter system is most suitable, since it has a greater degree of strength and makes it possible to lighten the roof structure, evenly distributing its weight over the entire frame of the building.

The hip roof rafter system can have several structures that are different in terms of installation method, each of which assumes the presence of certain features during assembly.

1. Traditional rafter system. In this design, the diagonal ribs rest on the support beam of the main ridge, and the overhangs are at the same height. Such a system consists of two isosceles triangles and two trapezoids.

   The truss system of a classic hip roof consists of two triangles and two trapezoids

2. Tent system. This design does not provide for the presence of a supporting ridge beam, because it is arranged above square buildings and consists of four identical triangular slopes. All diagonal edges converge at a common point, and short sprigs are connected to them. Only professionals can make a reliable ridge knot of a hipped roof.

   The tent truss system consists of four triangular slopes, converging with their upper parts to one point

3. Half hip design. Such a system provides for the presence of vertical parts in the gable slopes, in which standard windows can be installed.

   The half-hip roof has vertical sections of gables into which ordinary windows can be inserted.

4. Sloping roof (mansard). This is the most complex and time-consuming hip roofing system, since all the slopes have a different shape and area and diverge from each other at different angles. Such a roof allows you to most effectively use the area under the roof and create additional living quarters on it.

   A broken or mansard roof structure allows you to equip full-fledged living quarters in the under-roof space

How to calculate the rafter system for a hip roof

When calculating the design of the hip roof rafters, the following factors must be taken into account.

1. The degree of wind regional load. The larger it is, the smaller the angle of the roof slope should be and the stronger the system. The main supporting rafters should be made of thick timber.
2. The amount of precipitation. The more rain falls annually, the steeper the roof slopes must be in order to avoid great pressure on the rafter structure.
3. Material for covering the roof of the house. Depending on the type and weight of the roofing material used, the sheathing system is selected. This factor is taken into account at the stage of developing a house project.
4. Roof insulation. The width of the insulation, the grade and thickness of the beam are taken into account when calculating the installation step of the rafters.
5. The angle of the roof. The slope of the roof affects the choice of finishing material.

Each roofing material has its own allowable range of roof slope angles.

The angle of inclination of the roof slope determines the position of all rafters. The installation location of the intermediate rafters is calculated as follows:

1. An center line is drawn on the top beam of the side wall.
2. The middle of the ridge beam is determined in thickness and the location line of the first of the center intermediate rafters is beaten off.
3. The end of the measuring bar is connected to the location line of the previously marked center support rafter.
4. At the other end of the plank, the line for the location of the internal contour of the end wall is beaten off.
5. The point that will be obtained in the previous step will be the installation site of the intermediate rafter.

The relationship between the size of the rafters and the length of their laying (horizontal projection) is determined using a correction factor, the value of which is directly proportional to the angle of inclination of the slope. If you multiply the laying size by this factor, you can determine the exact length of the rafters.

Table: correction factors for determining the length of the rafters

bias roof slope	Coefficient for intermediate rafter	Coefficient for corner rafter
3:12	1,031	1,016
4:12	1,054	1,027
5:12	1,083	1,043
6:12	1,118	1,061
7:12	1,158	1,082
8:12	1,202	1,106
9:12	1,25	1,131
10:12	1,302	1,161
11:12	1,357	1,192
12:12	1,414	1,225

Formulas for calculating the design of rafters

In the process of developing a project for any roof, the exact angle of inclination of the slope, which is necessary for all subsequent calculations, should be determined.

Calculation of the hip roof area

The roof area is calculated as follows:

1. We determine the height of the ridge using the formula h \u003d d / 2 tg α (where d is the width of the building, α is the angle of inclination of the slope, h is the height of the ridge).
2. We calculate the size of the side rafters according to the formula c \u003d d / 2 cos α.
3. We find the length of the diagonal rafters l \u003d √ (h 2 + d 2 / 4).
4. We consider the area of ​​\u200b\u200bthe roof, for which we add up the areas of all structural elements (two trapezoids and two triangles):
   • the area of ​​the triangular slope S 1 \u003d 1/2 d/2 c;
   • the area of ​​​​the trapezoidal slope S 2 \u003d 1/2 (b + k) e, where b is the length of the eaves, k is the length of the ridge run, e is the height of the trapezoidal slope;
   • S = 2 (S 1 + S 2).

To determine the area of ​​​​the hip roof, it is necessary to use the area formulas for simple geometric shapes: a triangle and a trapezoid

Calculation of the distance between the rafters

Most rafter systems are created with a step between two rafters of 1000 mm. The minimum allowable pitch value is 600 mm.

1. We choose the approximate distance between the rafters, guided by the standard dimensions (for example, take this parameter equal to 0.8 m).
2. We measure or take the length of the slope from the project documentation. Let's say it is 12 meters.
3. We divide the length of the slope by the value of the rafter step chosen earlier, round the result up and add 1. We get 12 / 0.8 + 1 = 16.
4. We divide the length of the slope by the number obtained in the third paragraph. The final step of the rafters will be equal to 12/16 = 0.75 m = 75 cm. The resulting value will be equal to the distance between the central axes of the rafter logs.

Preparatory work

A drawing of a rafter system is a prerequisite for the construction of this type of roof, since there are no identical schemes that are ready for direct use without taking into account the specific type of building and the place of its construction.

The more complex the roofing system, the more accurate the calculations should be, since they will affect not only the quality of the work being done, but also their cost.

The drawing of the main components of the structure must accurately indicate the dimensions of all elements of the truss system, the location of the junction points of the diagonal racks to the ridge beam and the places where the rafters are attached to the Mauerlat.

Tools needed to assemble the structure:

• construction level;
• hacksaw;
• big hammer;
• long tape measure;
• building cord;
• stapler;
• electric drill;
• riveter;
• metal cutting scissors;
• nails;
• measuring bar.

Materials for work:

When installing a hip roof on a house made of timber that shrinks, experts recommend using special floating fasteners for rafters to compensate for the movement of the crowns.

When installing a truss system in a wooden house, it is recommended to use a sliding rafter attachment system, which compensates for the deformation of the building during its shrinkage

Video: ensuring the rigidity of the hip roof

Features of the hip roof truss system

All types of hip roof truss systems have identical parts that create the frame of the structure:

Video: we collect rafters

Technology for creating a hip rafter system

Since a large load is placed on the roof truss structure, all nodes and connections must be made in strict accordance with the technology, otherwise the roof will not be able to fully perform its functions.

Installation of the main components

Installation of nodes is reduced to the following steps:

1. We prepare the rafters. We determine the angle of inclination of the rafters, the length of short supports and sloping rafters, which carry a significant load. In order to get all the elements of the required length, we use the method of connecting the boards with an overlap. To do this, we lay two boards on top of each other with an overlap of 1 m and fasten them with nails arranged in a checkerboard pattern. This is the easiest and most durable way to splice rafter legs.

   The most durable and reliable method of splicing rafter legs is lap fastening.

2. We fix the Mauerlat. We mount the beam around the entire perimeter of the walls of the building in the upper part. We overlap the beam using a large number of attachment points with the base of the bearing walls. We fasten the connection nodes with metal brackets.

   Mauerlat beam is attached to the upper end of the wall with anchor bolts

3. Between the wall and the beam we lay a layer of roofing material to create a hydrobarrier. In brick, aerated concrete, foam concrete and wood concrete houses, a reinforced concrete belt is poured under the Mauerlat with pre-fixed pins for installing the beam. The pin must have a diameter of at least 10 mm and protrude approximately 30 mm beyond the belt. Step between pins - from 1 to 2 m.

   The roofing material layer creates a hydro-barrier between the Mauerlat and the wall of moisture-absorbing material

4. We install a bed - a central beam between the two short sides of the Mauerlat to provide additional strength under the rafters. Such a run is necessary to create a hip roof of a large area.
5. We mount the support stands. They act as supports for the ridge run.

   The support posts are mounted on the bed and serve as supports for the ridge run

6. We mount the ridge beam. When installing a hip roof ridge, accurate measurements should be taken, as the entire roof system will be supported on it. We check the accuracy of its installation with a level in height.

   Carrying out work on the installation of a ridge beam requires accurate measurements, since it carries the greatest load in the hip roof system

7. We nail the rafter legs. We mount the central rafters, and after them the diagonal ones. During installation, the lower part of the beams rests on the Mauerlat. This can be done in two ways: with a notch or with support posts. In the first case, we cut a groove in the Mauerlat, insert the rafters into it and fix them with metal corners. In the second case, we simply put the rafter on the Mauerlat and put a bar with an oblique cut under it. We also fix them with a metal corner.
   

   Rafter legs can be attached to the Mauerlat in two ways: with a notch and on a support bar

8. The device of the node on the ridge beam is produced by the “half-tree” method. To do this, we cut a notch at the end of the rafter legs, which should be equal to half the thickness of the board. Then we connect these notches with each other and fix them with nails or dowels. It turns out a strong ridge knot. For greater strength, we fix all nodes with steel corners.

   To create a strong ridge knot on a hip roof, the cutting method “in half a tree” is used

9. There is a lot of pressure on the diagonal rafters, so we strengthen them with the help of racks that we mount on the floor or set the struts at a certain angle. You can use a sprengel in the form of a T-beam, rotated 180 °.

   Sprengel is one of the auxiliary elements to ensure the necessary rigidity of the truss system, transferring part of its load to the Mauerlat

10. We mount ordinary rafters in the same way as the central ones, which form the edges of a trapezoidal structure. We support the bottom of the beam and fasten it to the Mauerlat, and rest the top on the ridge beam.
11. We install sprigs, which we make from a single board. In the place of their attachment to a long rafter, we make special cuts or put support beams and provide the necessary strength with the help of metal fasteners. To simplify the work, the sprigs can be installed apart.

    The spears are fastened with a cut into the rafter beam and are installed in a checkerboard pattern

All wooden parts of the truss system are treated with special refractory and antiseptic agents before assembly.

Video: hip roof truss system

Creating a hip truss structure is a long and complex process that requires attention to every specific detail. But if you correctly and accurately perform all stages of work, then as a result you will get a beautiful, durable and reliable roof for your home.

A hip roof is a roof that meets the requirements of aesthetics and originality to the maximum, harmoniously fits into almost any surrounding landscape. Moreover, its truss system is by far the most reliable geometric design for protecting the house from wind loads.

The main task of the roof is to protect the house from rain. In order for the roof to be as functional as possible, it is designed with a slope of slopes to remove the bulk of snow and rainwater. At the same time, the entire supporting structure of the rafters must be strong in order to withstand significant loads.

It will be optimal to perform such work with a classic gable roof, or a four-slope hip roof truss system: the construction scheme of such a design allows you to get a roof that is distinguished by:

• high reliability,
• versatility,
• long service life,
• the streamlined shape eliminates the effect of windage, that is, the wind load in the gable area.

Types of hip truss frames

This version of the truss system, in contrast to the classic gable, is an "envelope". In addition to the two main planes of the slopes, instead of the gables, two additional ones are assembled, in the form of a triangle, these are the so-called hips. By appointment, they are attic and non-attic.

It is worth mentioning right away that this type of roof is not suitable for arranging a residential attic floor, because the four planes of the slopes limit the internal space. However, if desired, you can use such types of structures as Danish or Dutch.

An example of a Danish roof with truncated hips

Semi-hip roof of the Dutch type with a residential attic

A hip roof is an excellent solution for buildings with original architecture that have elevations, ledges, various turrets, and an attic floor.

In both versions, a roof space is provided that can be used as additional living space. At the same time, the slopes of the roof planes do not significantly reduce the usable area due to the truncated hips.

1. The classic type of such a roof provides for full-fledged four slopes with diagonal rafters connecting the corners of the building with the top of the entire structure, which is crowned by a ridge of the required length. The following elements are used for this:

• Hanging rafters with all the details: beds, runs, puffs.
• Diagonal.
• Skew, forming the contours of the planes.

1. Another option is a tented hip roof, which is a rafter scheme, according to which the diagonal elements converge at one point, forming a pyramid or a tetrahedral tent in shape. The assembly of this design involves the use of layered and hanging principles for mounting frame parts.

The ideal option for roofing material for a hipped roof would be soft bituminous tiles, since large sheets of metal tiles or corrugated board will have to be cut, after which a lot of waste will remain.

All types of hip and semi-hip roofs are designed with plane inclination angles from 10-12 degrees to 60. It is most optimal to use the accepted conventional bevels at an angle of 25-30 degrees.

Hip roof truss system: device diagram

Work on the construction of the supporting frame of the roof is carried out in the following sequence:

• Mount Mauerlat.
• In the places where the racks will be located, lay down.
• They are installed on the bed of the rack, strictly vertically, for a ridge run. If necessary, the racks are fixed with struts.
• To fix the ridge fitting, use a level and a plumb line. The quality of the design depends entirely on the accuracy of the installation.
• The slats are mounted: the lower end is to the Mauerlat, and the upper end is to the ridge run.
• Using the same technology, installations are also installed intermediate.
• Mounted sprockets.

The device assumes the following supporting structures:

• diagonal;
• intermediate;
• sprigs (corner).

Installation of diagonal parts

Four diagonal (sloping) boards are directed to the outer corners and converge on the ridge run. Their lower supports may differ - it depends on the material with which the house is built:

• wooden chopped or block-shaped - the upper crowns at the log house;
• frame - top trim;
• brick (stone) - Mauerlat, through which the concentrated load from the wooden structure is distributed to the masonry walls.

• wooden beam with a square section (100 x 100mm). It is laid either in the center of the wall, or closer to the inner edge and attached to the wall with wire rods (this way you can protect the building from strong gusts of wind). At one end, the twist is screwed to a crutch, which is driven into the seam of the masonry (from the top of the wall by 300 mm), the other is attached to the beam.
• In order to maintain free access to the inspection of the rafter legs and, from the bottom of the Mauerlat to the top of the attic floor, leave a distance of at least 400 mm
• All places of contact between wooden elements and brickwork are insulated with a layer of waterproofing.
• The top of the boards rests on a ridge beam, which is a wooden beam with the same cross section. Due to the absence of brick gables in the construction of this type of roof, wooden racks (section 100 x 100 mm) are installed under the ridge beam, which are supported by the lower end on the bed, with a step of 3-4 m.

It can be placed:

• if there is an internal load-bearing wall on it - a board with a section of 50 x 150 mm;
• through the brick columns to the floor slab - a bar with a square section of 150 by 150 mm.

In any case, rolled insulation must be laid under the bed.

• Diagonal rafters are longer than usual ones, in addition, the sprigs rest on them, so the load that comes to them is one and a half times greater than that of ordinary ones. For this reason, sloping boards are made paired - they consist of two sections of ordinary ordinary boards.
• Supports (one or two) are installed under it in the form of racks made of timber or struts (the cross section of both is 100 by 100 mm). Thus, the estimated length of the oblique leg is reduced. The struts rest against the bed at an angle of 45 °.

Features and types of supports

Most often, in the construction of houses, they use the usual hip roof scheme, less often Dutch or Danish.

The support system for roof assembly can be used in two types:

• Hanging scheme of the truss frame. It is usually used in the construction of small buildings of residential buildings, in which the project does not provide for internal load-bearing walls. In this embodiment, the main vertical supports are installed on the ceiling beam in one row.
• Layered. If there are load-bearing walls inside the house, two or three rows of vertical supports can be installed. This simplifies the assembly of the hip roof, due to the presence of more attachment points, and also makes it possible to design.

note

When assembling, it is better to give preference to the latter option, which will make it possible to evenly distribute the weight, resting the rafters on several supports over the entire area.

Stops for diagonals are used in three types:

1. Rack. Usually a bar of a suitable section, installed with an emphasis according to one of the options. Between it and the ceiling (actually the ceiling), waterproofing is required.
2. Strut. It consists of two beams, resting their ends against the frame rack, and the other two support converging diagonal slope rafters. Their angle can vary from 45 to 53 degrees.
3. Sprengel. This is a beam that is laid on two walls converging at an angle. A vertical stand is installed on it, supporting the rafter in the lower part. Another version of the hip stop consists of two parts of a trussed truss, laid at the corners of the building. As well as the truss itself - a vertical strut supporting the diagonal, with an emphasis on the truss. With a small angle of structure, the snow load increases, so it becomes necessary to strengthen the wooden structure with a truss. If it is necessary to strengthen the upper part, a truss truss is already used. In this case, the sprengel (vertical strut) is reinforced with two struts.

Sprengel installation

Also, depending on the scheme of the frame, a different system of supporting the diagonal slanting beams to the ridge run can be used.

1. If there is only one run in the roof structure, which performs the function of a ridge, then the support is carried out directly on its console.

1. With the option of two runs, and using boards as rafter legs, the diagonal slanting beams rest on both runs.
2. In the case of two runs and the use of beams as slings. legs, the emphasis is on both runs. In the ridge area, diagonal slanting parts have a short piece (surf) as a support, stitching adjacent rafters.

The scheme of the emphasis of the rafters with an emphasis on the shorty

With this fastening, the heel of the rafter element is cut to the required angle, nails are used as fasteners, and if necessary, additional clamps are used to strengthen the connection.

The opposite end of the diagonal is fixed with emphasis on the Mauerlat, or the corner beam installed before it. In this area, staples are used as fasteners, or nails driven through a lining from a wooden lath.

Arrangement of sprockets and intermediate rafters

Narozhniki (corner elements) are called truss half-legs because of the shortened length. At one end they rest on a diagonal leg, and at the other end on a base beam. In order for the load on the slats from the corners to be evenly distributed, they are fixed in different places.

• The lower end rests on the Mauerlat, and the upper end rests on the ridge beam. Install in increments of 1.0-1.2 meters. The sections are calculated based on the beam scheme (one- or two-span), pitch and load from the weight of the snow cover and the frame itself. The load from snow is calculated taking into account the angle of inclination.
• The free length of the intermediate boards in the frame is limited. When flying over a building:

• 8 - 10 m - one support is installed under each leg (strut or stand);
• 10 - 12 m - two supports.

• Each second leg is attached to the wall with the help of twists (double wire, diameter - 4 mm), which, with the help of crutches, are hammered into the seam of the brickwork 300 mm lower from the edge of the wall.
• Intermediate rafters and Mauerlat are connected using a back bracket.

Fasteners

Narozhniki are installed as rafters on the diagonals of a sloping roof. With the help of them, the hips themselves are formed, and the triangular sections of the main planes of the roof.

Installation of outdoor parts is carried out in two main ways:

• By cutting. On the diagonal, a selection of material is made, forming a nest for the heel of the sparrow. The location between them must be at least 200 mm, while on both sides the cutting is done so that it does not coincide.
• With preliminary installation of cranial bars. In the lower part, on both sides of the diagonal rafter, a beam with a section of 50 × 50 mm is stuffed along the entire length of the sloping beam. In this case, the guards cut under the cranial bar, and rest one against one. Such a scheme is more preferable, since the design is much more rigid due to the additional stop.

However, before proceeding with the purchase of materials, as well as assembly according to the selected scheme, all calculations of the parameters of the hip roof must be made.

The hip roof is perhaps the most popular type of hipped roof. It is suitable for covering private houses of large and small areas, baths, even gazebos. A recognizable geometry is given to it by a truss system, a set of supporting elements that work like a frame.

The complexity of this design lies in the large number of components and attachment points that require special skills and experience. This article will answer questions about what it consists of, what materials are used for construction, and how installation work is performed.

hip roof construction

The hip roof belongs to the four-pitched type, that is, it is formed from four slopes, planes that have one common side. Two slopes that replace the pediments are called hip or end, they have a triangular shape. And the other two, in the form of trapeziums, are designated by the term facade. The line in which all four slopes converge is the ridge, the highest part of the roof. The hip type design consists of:

1. Hip slopes, which have the shape of a triangle, are located in a place belonging to the gables.
2. Facade slopes of a trapezoidal shape.
3. The ridge, the line that the upper connection of the rafter pairs, the tops form.
4. An overhang that protrudes beyond the perimeter of the house of the part of the roof formed due to the length of the rafter legs or filly. It protects the surface of the walls from melt and rain water.
5. The truss system of the hip roof, the frame supporting and distributing the weight of the roof structure.
6. Roofing material, a coating that is laid on the rafters of a hip roof to protect against precipitation.
7. Gutters, drainage systems for water accumulating on the roof. It consists of a gutter, a funnel and a downpipe and carries moisture from the surface of the blood to the storm sewer.
8. Snow retainers, elements that prevent snow masses accumulated on the roof from collapsing and injuring people passing by.

Types of truss system

The hip roof truss system can be of three types, depending on how the rafters are located:

• Hanging. This means that the rafters are supported by two points: in the upper part on the ridge run, and in the lower part on the Mauerlat. The hanging truss system experiences deflection, compression and expansion loads. All these forces have a destabilizing effect on it, so additional compensating elements are needed - puffs, crossbars, grandmothers. They complicate the design and installation of a hip roof, so experienced roofers are advised to abandon the hanging rafters, if possible.
• Naslonny. With this type of hip roof truss system, the rafters are supported by three points: at the top on the ridge, in the middle on the rack, and at the bottom on the Mauerlat. Racks are installed on internal load-bearing walls. Additional vertical supports reduce the deflection of the rafter legs and eliminate the bursting force. Therefore, a layered system is considered more reliable and stable than a hanging one, and besides, it is easier to install.
• Combined. This term means that the rafter system consists of alternating layered and hanging elements. This is possible if not an internal load-bearing partition is used as a support for the rack, but a pole or column. The roof turns out to be of an open type, that is, all beams and racks are not hidden by the sheathing, but are visible.

Important! With the help of a hanging truss system, it is possible to cover a building no more than 6 meters wide. The use of layered rafters with one additional support increases this distance to 12 m, with two - up to 18 m.

Material used

The hip-type roof truss system consists of many components that reflect the drawing, they are made of the following materials:

Properly processed and prepared wood is an excellent material for the manufacture of a truss system. It is much easier to work with it, it does not require special tools. A good price will keep costs down. Moreover, only those who are confident in the margin of safety of the foundation can afford the metal frame of the roof.

System elements

Depending on the area and features of the layout of the house, the hip roof truss system takes on various types, but it is based on the following elements:

Note! Some elements of the hip roof truss system are of considerable length. And the standard size of sawn wood is limited to six meters. To get out of this problematic situation, roofers make glued or stacked rafters, made up of two or three parts.

Mauerlat installation

Mauerlat installation is the starting point for creating a truss system for a hip roof. Proper installation will provide a solid foundation for the rafters. During the construction of a house from a bar or log, the role of the Mauerlat is performed by the upper crowns. In structures made of bricks, gas silicate blocks, it is fixed as follows:

• On the upper section of the walls, the formwork is adjusted and a concrete belt reinforced with reinforcement is poured into which metal studs are embedded.
• Mauerlat timber is treated with a deep penetration antiseptic and holes are made in it for studs. Moreover, the location of the holes is calculated in such a way that they do not coincide with the attachment points of the rafter legs, but are located between them.
• After the concrete belt hardens, which occurs within 2-3 days, waterproofing is mounted on it. These functions are usually performed by a roofing material folded into two soybeans.
• Mauerlat is laid on waterproofing and attracted with metal studs.

Please note that a large number of holes reduce the strength of the Mauerlat, provoke the appearance of cracks, defects, reducing its support functions. Remember, in the Mauerlat they never cut under the rafters, it is impossible to violate its integrity!

Assembly steps

The result of the calculation, made manually or by the program, is fixed by creating a drawing that reflects the dimensions and relative position of the elements of the truss system, and then they begin to assemble it according to the following plan:

Competent calculation, detailed drawing and high-quality installation are the key to a long service life and reliability of the roof truss system.

Video instruction