Diy gable roof rafter system

Recommendation points

• The device of the rafter system. Nuances
• Training
• Hanging rafters for small span
• Option 1. With subfloor
• Option 2. Without subfloor
• Rafters
• Rafter step
• Rafter length

How to make a rafter system with your own hands? What are the options for attaching rafters? From the article you will learn how to arrange hanging or layered rafters and in what cases they are used. We will give examples of professional techniques when creating a gable rafter system.

In previous articles, we talked about the rafter system and the features of the gable roof device. In this article, you will find step-by-step tutorials for DIY installation. In order to follow the manual exactly, the necessary terms will be given, without understanding which correct installation will be impossible..

The device of the rafter system. Nuances

Gable roofs fundamentally differ only in the way the rafters are arranged – hanging or layered – which directly depends on the length of the span. In this tutorial, we’ll cover both and use a set of basic terms.

Attic height– the distance from the top of the wall (the place of the rafter supports on the wall), either from the upper plane of the Mauerlat, or from the upper plane of the floor beams to the upper point of the ridge of the gable roof.

Projection of the working part of the rafters(hereinafter – the projection of the rafters) – the distance from the ridge to the point of support of the rafters on the wall or floor beam horizontally.

Cut– interfacing (connection) of wooden parts by creating an anchor and a seat, or a link or stop from the body of the tree of the element itself. Basically, the notches are reinforced with various anchors – a wooden chop, threaded rod (stud), self-tapping screws, turboprops.

1 – roof overhang; 2 – wall; 3 – beam; 4 – bed; 5 – intermediate rack; 6 – the height of the attic; 7 – central rack or “headstock”; 8 – rafter; 9 – the working part of the rafters; 10 – skate; 11 – projection of the working part of the rafters

The rest of the basic terms are given in the previous articles..

Their function in the support area can significantly affect the design of the rafters. Supports are of three types.

1. Support without cutting and cutting. It is used only on temporary, auxiliary buildings, or for a roof that does not carry significant loads. In such cases, a powerful wedge is installed in size..

Support without cutting: 1 – rafters; 2 – wedge; 3 – beam; 4 – armopoyas; 5 – mauerlat

2. Support on full cut or end cut. The rafters rest on a beam or Mauerlat on the area of ​​the entire cut or on the end tooth. In this case, to create a roof overhang, a filly is built up or an additional counter-lattice is mounted. Usually, this method is resorted to when the length of the slope is approximately equal to the length of one unit of material (board, timber) adopted for the rafter leg (as a rule, 5–6 m). This is done in order not to splice the rafters in the working part..

Support on a full cut or end tooth: 1 – beam; 2 – end tooth; 3 – wedge; 4 – cut; 5 – studs with nuts; 6 – rafters

3. Support on the intermediate cut. The rafter leg remains solid from the ridge to the edge of the roof, that is, the extreme part of the rafter leg performs the function of the overhang. The most common option with a slope length of more than 5 meters. In this case, the splicing of the rafters is inevitable. The cut provides additional grip for rigidity, and the sufficient length of the rafter leg guarantees the optimal length of the roof overhang. The depth of the cut into the rafter leg should not exceed 40% of its height.

Support on an intermediate cut: 1 – Mauerlat; 2 – support bar; 3 – studs with nuts; 4 – beam; 5 – wedge; 6 – rafters

To create a gable rafter system with your own hands, you will need a carpenter’s tool kit:

1. Power tools – circular saw, jigsaw, powerful drill with a set of “feathers” for wood.
2. Hand tools – saws, ax, hammer, sledgehammer, chisel set, locksmith wrenches.
3. Measuring instrument – tape measures, levels, hydrolevel, usually, cord, plumb.

Training

In preparation for work, it is necessary to create drawings or sketches. To do this, you need to decide on the choice of the principle of the roof device and draw specific nodes:

1. Rafter leg support assembly. Here it is necessary to take into account local conditions – the material of the walls and the distance between them.
2. Skate. This is an equally important area and the method of connecting the rafters must be selected in advance, based on the dimensions of the projection of the rafters, the span and the thickness of the beams.
3. The choice of material for the truss system. If nodes are selected that provide for a through screed in width, then the thickness of the rafter leg must be at least 60 mm. If the rafters of such power are not needed, choose another version of the rafter support (for example, “in the overlay”).

Overlay cut: 1 – cut on the side of the beam; 2 – departure; 3 – studs with nuts; 4 – top view

Hanging rafters for small span

The method of constructing a rafter system without intermediate supports is applicable only in the case of a small span – up to 6 meters. As mentioned in the previous article, in this case, a floor beam or a rafter is used as a tightening. We will consider two options for installing rafters.

Option 1. With subfloor

This method is convenient if it is possible to arrange a rough floor along the floor beams..

Operating procedure:

1. Arrange a rough floor from unedged boards and scrap material.
2. Mark out the Mauerlat or beams – a step, notches. Pull the cord over the future skate. Be sure to check the perimeter.
3. Apply material for rafters to the floor.
4. Choose the best option for attaching rafters in place.
5. Craft two roof trusses *.
6. Install end trusses using temporary struts (lighthouse trusses).
7. Check correct installation, compliance with levels and tolerances.
8. Make and install the rest of the trusses according to the size of the lighthouse trusses on screws and nails. At the same time, it should be possible to correct the step and dimensions.
9. After the installation of all trusses, the compliance with the levels and tolerances should be checked again.
10. Final release of the rafter system – installation of ties, brackets, turboprop and other elements provided by the project.

* FROMtropical farm – one complete element of the rafter system.

Option 2. Without subfloor

In this case, the overlap is not arranged, the floor space is combined with the attic.

Operating procedure:

1. Measure the dimensions carefully at the installation site.
2. According to local dimensions and conditions, choose a way to support the rafter leg and tie the ridge, the option of cutting the slope.
3. Create a polygon that repeats the dimensions of the span and the projection of the rafters. Install a system of stops on a horizontal grate or workbench, guiding the board to the design position in the truss.
4. Build one experimental roof truss.
5. Raise the truss to the place of installation and install it on temporary fasteners.
6. Select a cutting method locally and make a cutting for an experimental farm.
7. Correction of dimensions, angle and structure if necessary.
8. After reaching a high-quality landing, finally fix the truss nodes and lower it to the landfill.
9. Correct the stops of the polygon (workbench) according to the template.
10. Build the required number of roof trusses using the experimental truss as a template.
11. Make cuts or footprints at anchor points.
12. Install and unfasten a number of roof trusses in the design position.

Often the project provides for the unification of space on large spans – up to 9 meters. In this case, hanging rafters with a rafter are also required. Such projects must necessarily take into account three points:

1. The rafter leg must be made of a board with a thickness of at least 75 mm and a width of 200-250 mm.
2. All cuts, anchor points, mating points must be tightened with a through threaded tie (hairpin) with a diameter of at least 12 mm. It is advisable to cover the joints of the planes with joiner’s glue..
3. The level of installation of the rafter beam (tightening) – from 1/2 to 2/3 of the attic height.

Otherwise, the technology for installing rafters repeats the described options.

Rafters

The device of this type of roof will require developed carpenter skills. This type of rafter is suitable for large spans and in the case when the attic space is planned to be used separately. Before installing the rafters themselves, additional preparation is required:

1. A plank should be installed under the vertical supports – a board or timber with a thickness of at least 60 mm.
2. Since roof trusses have a larger number of elements, they are only assembled locally. This may require a scaffold device.
3. Mauerlat is an obligatory element of the system. It should be fixed to the armored belt with anchors and connected at the corners with half-wood cuttings.

The thickness of the board for the rafter legs and intermediate supports (if any) is at least 50 mm with a width of 150 mm. It is advisable to make the central support (headstock) from a bar 100×100.

Installation of rafters. Operating procedure:

1. Install Mauerlat. Usually it is mounted on the inner plane of the bearing walls. Based on the fact that the thickness of the wall is obviously thicker than the width of the Mauerlat, the distance to the edge of the wall will allow it to be insulated. Docking of elements – only through a cut-out with fixation with brackets or ties.
2. Install a row of central supports on the bed, securing them to the design position with temporary rods (rail). Attach a temporary or permanent ridge run to the tops.
3. Temporarily fix the rafter foot board in the desired design position. Moreover, it does not need to be cut or trimmed in advance..
4. Correct the ridge girder.
5. Mark the seats on the headstock, rafter leg and Mauerlat and make cuts.
6. Install the rafter leg in the seats, measure and check for correct installation. Correct footprints if necessary.
7. Make cuts and cuts for the entire row of rafters of one slope, observing the step.
8. Make cuts and cuts on the rafter board for one ramp (wing) according to the template.
9. Install a row of rafters of the ramp on temporary clamps (screws, corners).
10. Adjust the opposite roof slope in the same way.
11. Check for correct fit and tolerances. Fasten the trusses with a transverse crate.
12. Install the beds under the intermediate supports (if any) and the supports themselves.
13. Mark and cut in place the cut of the roof slope and install, if necessary, a wind board.

A variant of the truss system device: 1 – wall; 2 – Mauerlat; 3 – bed; 4 – rack; 5 – rafter; 6 – “grandmother”; 7 – run; 8 – ridge run; 9 – intermediate cut; 10 – cut in half a tree; 11 – studs with nuts

Rafter step

When selecting, observe the rule: The step of the rafters should not exceed ten times the thickness of the rafter leg.

This rule also applies in the opposite direction: The thickness of the board for the rafters should not be less than 1/10 of the step of the rafters (along the axes).

The most popular step – 600 mm between the inner planes of the sinus – is due to the standard width of the slab (sheet) of mineral wool insulation, which enters such a sinus without undercutting. The thickness of the board should be 60 mm..

Rafter length

This indicator can be calculated in advance, as the hypotenuse of a right-angled triangle, using the formula from the Pythagorean Theorem:

• c² = a² + b², Where
• a – projection of rafters
• b – attic height
• c – the length of the working part of the rafter leg

However, this does not take into account the roof overhang. Therefore, it is recommended to adjust the length of the rafter row in place, trimming the ends after installation. This makes it possible to make the ends smooth. Optimal constructive roof overhang – 600 mm.

When creating roof rafters with your own hands, remember the danger of unreasonable savings. The rafter system, like the load-bearing walls and foundation, is an irreplaceable element of the building. This means that complete dismantling is required to replace it. As a rule, this happens during renovations or major repairs. If the rules described in the article are not followed, this procedure may be required after 2-3 years.