Gable roof system - how to make a truss system

The gable roof due to its simple, reliable and presentable construction has been popular for many years. Depending on the slope of the slopes, it is used in regions with different amounts of precipitation. The rafter system of the gable roof provides a natural gathering of precipitation.

Gable roof models

Gable roof system - how to make a truss system

  1. Symmetrical - both slopes have the same length and are mounted at the same angle. Such a roof is an isosceles triangle with a blunt or acute angle.
  2. A broken roof is created to accommodate an attic room, its truss system implies a complex, two-level structure.
  3. Different angles of the slopes - this is the original design, emphasizing the unusual architecture of the house.

Gable roof system - how to make a truss system Broken gable roof (attic)

Tilt angle value

The angle of inclination is selected after analyzing several indicators: the type of roofing, the amount of precipitation, and the wind load. For regions with heavy rainfall, a small angle of slopes is recommended, but not less than 5 degrees. Snow masses do not linger on a steep surface. Flat roofs with a blunt angle of slopes are suitable for a windy climate.

Gable roof system - how to make a truss system Tilt angle

A truss gable roof system must comply with accepted safety standards and be built according to standards.

Systems of rafters

Gable roof system - how to make a truss system Suspended rafters of the sloping roof

Bearing elements and rafters accept assume the load from external forces and redistribute it to the walls of the building. From their reliability depends on the strength of the entire roof. When constructing a structure, two systems of rafters are used:

  • Hanging - truss legs have two points of support on the walls of the building. They have a strain on compression and bending. When the distance of the span, exceeding 8 meters, the installation of the headstock with struts is required. To reduce the impact of rafters on the walls of the building, they are connected by pulling.
  • Suspended - these bars have a support on the inner wall or a special construction.

Gable roof system - how to make a truss system Suspended rafter gable roof

If you can not use one of the systems in its pure form, resort to a hybrid design that allows alternating hanging and nasylon rafters.

Calculation of materials

The device of the roof system of a gable roof allows you to perform calculations independently, based on knowledge of geometry. To calculate the area of ​​the structure you need to set the length of the slope. The amount of material required depends on the angle of inclination. The acute angle allows you to save, but at the same time minimized attic space.

The height of the ridge, the length of the rafters and the area of ​​the roof will be calculated using geometric formulas. For clarity, suitable scheme at home. Example - take the slope of a slope at 45 degrees, the width of the house (the base of an isosceles triangle) is 6 m, and the length is 10 m.

Gable roof system - how to make a truss system

First, divide the triangle in half by the height lowered from the top angle. It turns out two right-angled triangles, and one of their legs is the desired height of the roof. The height divides an isosceles triangle in half, which means that one leg is 3 m. The second one is calculated by the formula:

3 * tg 45 0 = 3 m.

Knowing the legs, the Pythagorean theorem we calculate the hypotenuse, which is rafter:

3 2 + 3 2 = X 2 .

The length of the rafter will equal the square root of 18, approximately 4, 25

The number of rafters is calculated by dividing the total length by a step (0.6 m):

10: 0, 6 = 16.6 - this value needs to be doubled.

Area is calculated by multiplying the length of the slope and the house and multiplying the value by 2:

4.25 * 10 * 2 = 85 m 2 .

Using various formulas, you can calculate the required amount of materials.

Installation of the truss system

Gable roof system - how to make a truss system

The bearing base for the roof is the mauerlat, a strong beam with a cross section of 150 * 150 mm from treated coniferous wood. Its fastening is performed on an anchor, immured in the upper row of the masonry. They should rise 2-3 cm above the bar to provide a place for tightening the nut. A ruberoid layer is laid under the mauerlat to protect it from moisture. Between the walls is laid transverse timber, fastening the mauerlat and protecting against longitudinal loads. To maintain the ridge, a special timber is laid along the slope - a lay, with a section equal to the mauerlat. With a significant width of the building installation of runs is necessary.

Gable roof system - how to make a truss system Fastening the rafters to the mauerlat

The rafters cross-section is determined by the pitch and length of the rafter, usually the board 50 * 150 mm. Rafter trusses are easier to assemble on the ground and ready to serve on the roof. For the template are taken two boards, equal in length to the rafters, and are connected with a nail. The free ends are placed on supports, the resulting angle is fixed with a crossbar. Places and the shape of the gash are marked with the help of the second template made of plywood.Bars are fastened at the right angle with bolts, they are washed down, and after the truss they are lifted up for mounting.

Gable roof system - how to make a truss system Methods of fastening a ridge beam

First, the rafters are installed on the gables. They are attached to the mauerlat with the help of corners or brackets. The first farms are set strictly on the level. A cord is drawn between them, which is a guideline for installing the remaining elements.

To give sufficient rigidity to the whole structure, the struts and girders are attached to the rafter leg. The ridge girth is bolted to each truss. This connecting element should be made of durable timber.

Gable roof system - how to make a truss system Rigid fastening of the ridge bar

With a significant building width, the installation of runs is necessary; this is a horizontal beam of the size 50 * 150 mm supporting rafters. For its installation install vertical racks, based on the ground. These elements will form the basis of the framework for the attic.

In order to avoid water running onto the walls, it is necessary to provide an overhang; for this, the rafters are made hanging down 30 cm or additional boards of “fillet” are attached.

Gable roof system - how to make a truss system Installation of fillings

A crate is made on the finished rafters, the necessary pitch is chosen for each roofing material shingles performed solid flooring. Warming of the roof is an important part of the construction. You can reduce heat loss to a minimum by correctly laying the insulation. Basalt wool is taken for this purpose, the width of the material is equal to the step between the rafters, which allows you to quickly and reliably perform insulation. Laying waterproofing will help to ensure reliable protection of the roof from moisture.

Gable roof system - how to make a truss system Warming scheme with basalt wool

Symmetrical model of a gable roof is the easiest to build and reliable in operation option. The load in the truss system is distributed evenly, which allows to extend the service life of the structure. Visual video lessons will help to master the subtleties of work.


This video explains how to build a roof system for a gable roof:

In this video you can see a roof system using the example of a single roof gable :

Read also:

Mansard roof with your own hands

Flat roof with your own hands


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