If you want to make a roof yourself, you have found the article you need. Do-it-yourself gable roof truss system is not so difficult. Of course, this is almost impossible alone, but a team of 3-4 people is quite capable.
Of course, the main purpose of the roof is protection from the forces of nature in the form of precipitation and extreme temperatures. But the beauty of the building, the atmosphere that the architecture creates, including the roof, says a lot not only about the architect, but also about the owner of the house in almost every respect: tastes, finances, upbringing, worldview.
A wide variety of forms have given us modern technology and the release of fantasy in people.Just ten years ago, the appearance of houses in cottage settlements was dully monotonous, like in Soviet high-rise buildings, everyone built standard projects.
It was easy to get lost, like in a famous old movie.
It has become very fashionable to make an attic floor under the roof - romantic, and there are no extra rooms.
Roof types
The supporting structure of the roofs, in turn, rests on the walls of the building, transferring its weight, the weight of precipitation and wind loads.
There are three types of roofs:
- shed roof, used in the construction of household and outbuildings, but sometimes for residential buildings, when this is required due to requirements or such is the architect's idea;
- a gable roof is most often used for the construction of low-rise country houses, it is already easier to make an attic here, especially a broken gable roof for attics and is built specifically;
- the roof is multi-pitched, the so-called - hip; only more experienced specialists with the appropriate equipment can build such a complex structure.
We will only talk about the second type of roofs, since almost everyone can do the construction of a gable roof with their own hands. Moreover, such roofs are often made for a country house.
The main wood material used for such roofs is:
- edged board section 50 by 150 mm of coniferous species;
- beam with a section of 150 by 150 mm.
Rafter system for a gable roof
Gable roof: truss system most often depends on the plan of the building. Are there intermediate walls, are they bearing, what shape is the house. First, in the plan of the house, you need to draw the location and count the number of rafters.
There are hanging rafters when there is no intermediate support, or an attic or attic room is planned. Draw cuts along the rafters to clarify for yourself how much material is needed for one truss truss.
Draw a drawing of a gable roof and a facade view, where it will be seen how many rafters are needed, and how many battens for fixing the roof.
The drawing is especially useful if it is decided to make an attic, and you need a truss system of a gable sloping roof, which is much more complicated than a conventional gable. By drawing cuts in the indicated directions, you can easily estimate the required amount of material and time to manufacture the structure.
The gable roof truss system has a step, which is determined by the size of the building, the weight of the roofing material and the thickness of the rafter beam. To strengthen the structure, support frames are built, which are visible in the figure.
These frames are placed closer to the middle of the inclined elements, so that the effect of them would be more significant.
Support frames increase the rigidity of the structure and reduce the sag of the inclined element. In addition, these frames can be used as fasteners for the walls of the attic floor. It can be seen that some of the elements protrude beyond the walls to create a visor.
In addition, the figure shows support beams (Mauerlat), which are anchored to the outer walls with anchors. If the structure is not attached to the load-bearing walls in the middle of the sag, it is necessary to increase the cross section of the floor beams.
If the base frame gable mansard roof located above the load-bearing walls inside the building, due to this, part of the weight and wind loads from the roof will be evenly distributed over the walls, which will increase the strength and durability of the structure.
Calculation of materials and dimensions
In the simplest case, the roof section is an isosceles triangle. To calculate such a design, higher mathematics is not needed, school knowledge of geometry is enough.
Consider what the frame of a gable roof consists of.
The finished scheme, such a design as a gable roof is shown in the figure.
These are the ribs of the trusses, each truss - rafters, connecting at the top, which rest on the walls of the house below. Naturally, the steeper the angle, the more materials are needed.
The minimum angle depends on the material of the roof.
The maximum angle depends on your plans to make or not an attic space. Pitched roof nodes require fastening with special metal plates with many holes.
Calculation
How to calculate a gable roof?
The isosceles triangle theorem states that the height between equal sides divides a triangle into two equal right triangles.
To calculate the material, in addition to height and width, you need to know the surface area of the roof.
Using a specific example, we will show how to calculate the area of \u200b\u200ba gable roof.
If, say, a house with a width of only W \u003d 4 m. With an angle Y \u003d 120 degrees of rafters in the ridge, the angle of inclination of the roof will be 30 degrees, so the height of the roof will be
Let's consider all the calculations on a specific example. Let's say we have a house with a width of W \u003d 4 m, with an angle of inclination of the rafters in the ridge equal to Y \u003d 120 degrees:
H \u003d 0.5 * W / tg Y / 2 \u003d 0.5 * 4 / 1.73 \u003d 1.2 m
and the length of the rafter leg C will be equal to half the width divided by the sine of half the angle in the ridge:
C \u003d 0.5 * W / sin Y / 2 + 0.5 \u003d 0.5 * 4 / 0.87 + 0.5 \u003d 2.8 m
Advice.Do not forget to take into account the allowance for the roof peak of about 0.5 m.
With a house length of D = 6 m, and a distance between the rafters of 1 m (roof made of metal), the roof area is obtained:
Roofs \u003d L * C * 2 \u003d 6 * 2.8 * 2 \u003d 33.6 sq.m
So much you need the minimum area of sheets of metal.
With a distance of d = 35 cm between the battens, it will take about
Lattice \u003d C / d * D * 2 \u003d 2.8 / 0.35 * 6 * 2 \u003d 96 linear meters m
There will be 7 rafters in total with the same distance between them. And the timber for the rafters and the mauelrat will need no less than:
Lbar \u003d (2 * C + W + H) * 7 \u003d (2 * 2.8 + 4 + 1.2) * 7 \u003d 75.6 linear meters
Similarly, you can easily calculate the rest of the necessary materials, and finally begin the construction of a gable roof.
We are building
Floor beams are laid on top of the walls. If there is a simple attic, beams can be made from prepared boards. If you want to make an attic, you need a larger section of the bars, and you need to lay them only on load-bearing walls.
Advice. These beams must be made with a release of half a meter. This is necessary to protect the walls from rain and melting snow.
Boards are laid on top of the beams, like the floor of an attic or attic. The boards are fixed along the walls, perpendicular to the rafters. In addition, rafter parts will be attached to these boards: racks and struts.
Often individual trusses are made on the ground and then raised to roof level.
It all depends on the experience of the people who, together with you, make the rafters of the gable roof.
If you are making a gable, install it before installing the rafters. The pediment is a load-bearing truss with a ridge.
The rafters rest against the ridge with the upper part, and at the bottom - on the mauelrat and floor beams.The rafters and the pediment are made of boards with a section of 50 by 150 mm of coniferous wood. The boards in the rafters are placed on edge to maximize strength.
Advice. If your rafters will not be attached to the mauelrat, but to the floor beams, make thrust bearings on the beams. Lean the "leg" already fixed in the ridge against the beam. Draw lines along the edges of the board and cut the beam where the "leg" of the rafter will be attached.
In the upper part of the "legs" of the rafters are connected with a special "lock". In the planes of their contact, a half-width “leg” is cut. Across them are connected with a short headstock board. For even greater rigidity, the rafters are reinforced with crossbars.
When assembling rafters, you can use a variety of fastening methods:
- nails,
- screws,
- wire,
- overhead squares and strips with holes.
More tips
- before fixing, always check the verticality of the installation of the rafters with an ordinary plumb;
- start the installation from two extreme opposite farms. A cord is pulled between them for reference. The rest are easy to put in place along the cord;
- for structural rigidity, struts are added, which further reduce the slack of the rafters, they are attached to the middle of the inclined leg, the other end rests against the rack, and is fixed with nails.
For simplicity, we will talk about the construction of a roof for a rectangular garage.
Let the rafters of a gable roof be of a layered type, assembled in parts.
- Along the perimeter of the walls we lay the mauelrat beam. This timber is attached firmly to the walls with anchors.
- Nests are made in the mauelrat beam for a retaining beam.
- Between them, a gap is first attached with a puff length (the distance between the mauelrat bars along the width of the house).
- A support is attached to it in the middle, on which there will be a ridge beam at the top.
- Two "legs" of the rafters are attached to the support at the level of the ridge and with emphasis on the puff.
Advice. The rafter legs are made according to one template in order to make it faster, but make a small margin so that it can be adjusted at the exact point of attachment in the ridge.
Complete rafter assembly
Further assembly is performed in this order.
- Install the extreme pairs of rafter "legs" at both ends of the roof.
- The distance between the rafters is from 0.6 to 1.2 m, depending on the material and, accordingly, the weight of the roof.
- To increase rigidity, the rafter pairs of "legs" are attached to the mauelrat with anchors or wire, and below the ridge - between themselves.
- After installing the rafters, we fill the crate from the bottom up, in a plane perpendicular to the plane of the rafters.
Advice. Between the walls and the mauelrat, it is necessary to put waterproofing, usually from roofing material. This is necessary for concrete and brick walls.
Now you can cover the rafters with roofing material: slate or metal tiles, etc., deal with waterproofing and attic.
For those who know that it is better to see once than hear a hundred times: Gable roof truss system: video allows you to examine in detail the construction process and various subtleties of technology.
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