A roof made of four slopes - what is it good for? The numerous operational advantages of this type certainly outweigh the disadvantages. Is the rafter system of a hipped roof as simple as many construction beginners think? You will definitely find out soon! Important nuances and features of construction stages hip roof we will describe in this article.
What do you need to know about hip truss systems?
There are two options for hip roofs: hip and hip. The first type has the shape of a rectangular envelope, consisting of two main trapezoidal slopes and a ridge, and two pediment (side) slopes - triangles:
A hip roof is four identical isosceles triangles connected at one top point (reminiscent of a tent):
Both options provide for the installation of both layered and hanging rafters, which are installed using standard technologies.
How to choose the type of rafter system for a 4-pitched roof?
In the absence of a central roof support, the choice is made in favor of a hanging rafter system. If you can find upper and lower supports for each rafter, then you should choose a layered structure. This option is simpler and more accessible for non-professional craftsmen. You just need to remember two main conditions: when rigidly fastening the bottom and top of the stops, a reinforced Mauerlat is needed, since the thrust is transferred to it; with a hinged fastening or a semi-rigid connection (for example, the top is hinged and the bottom is rigid or vice versa), the Mauerlat does not need to be reinforced:
The choice of one type of hip roof should be determined by the shape of the house itself. For square houses, hip rafters are erected, for rectangular ones - hip rafters. Also, you can find complex multi-pitched roofs of a combined type, which contain both hip and hip elements.
Both hip and tent structures retain the main functions of a gable roof (for example, the possibility of arranging an attic) and look very aesthetically pleasing:
Why is a hipped roof more popular than a gable roof?
“Why the extra headache and difficulties?”, you ask: “After all, you can build a simple gable roof much faster and cheaper.” Here the masters emphasize some important points in favor of choosing exactly four slopes for the roof:
- High wind resistance. Four pitched roof has no pediments, all its planes are inclined towards the ridge. This structure minimizes the impact of strong winds and reduces possible destructive consequences to “0”.
- The most successful load distribution. Multi-pitched roof can withstand maximum amount precipitation, since the gentle slopes take part of the main load. Therefore, sagging, deformation and destruction of the rafter system, in in this case, have minimal probability.
- Availability of choice of any method of roof insulation. Straight gables require a special approach when choosing the type of roof insulation, since they are located vertically and are subject to wind blowing. The gentle slopes of the hip and tent systems allow you to evenly insulate the roof with any available material.
In addition to the listed “advantages”, a roof with four slopes perfectly conserves heat, can be covered with any roofing material and always has a neat appearance.
Construction of a four-slope rafter system
The hipped rafter structure consists of the following elements: Mauerlat, ridge beam, central and hip rafters, sloping legs, as well as beds, racks, crossbars, struts and other reinforcing parts. Let's look at the most basic elements.
I. Mauerlat
Mauerlat is the most important detail structure, since the entire rafter system rests on it. It is a powerful wooden beam 100x200, 100x250, 100x100, 150x250, 200x200 cm. The mauerlat is made from solid high-quality wood, mainly coniferous species. The rafter system of a hip roof, like any multi-pitched roof, requires thorough fastening of the base beam. The procedure for installing the Mauerlat in this case: formation monolithic foundation at the end of load-bearing walls with the installation of spiers; laying waterproofing; processing and installation of Mauerlat around the perimeter of the entire house; reinforced with anchors and other fastenings for maximum reliability of the base.
The Mauerlat can be laid on the edge of the wall, or in a pocket provided for laying bricks with inside load-bearing walls.
II. Sloping legs
Sloping legs are the four corner rafters that rest on the edges of the ridge and the corners of the mauerlat. They are the longest among all rafter legs systems, therefore must have a cross-section of at least 100x150 mm for maximum rigidity.
III. Ridge beam
Ridge purlin is a horizontal beam that connects all the rafters, the top of the rafter system. The beam must be strengthened with racks and struts. The ridge must be positioned strictly parallel to the plane of the attic floor and perpendicular to the racks.
IV. Rafters
Rafters for a hipped roof are divided into: central (attached to the mauerlat and ridge); main hip ones (attached to the ridge axis and Mauerlat); intermediate and shortened (installed on sloping legs and Mauerlat, connecting the corners of the slopes).
V. Strengthening elements
Additional reinforcing elements include ridge beam posts, crossbars or floor beams, rafter struts, wind beams, etc.
DIY rafter system for a hipped roof
Let's consider step by step process construction of the truss structure. For clarity, we have chosen the most popular option - hip roofing. The hip roof rafter system, a diagram of which step by step, is presented to your attention below:
Step I: Create a Project
To depict your version of a hip roof in a drawing, you need to calculate the height, length, slopes of the slopes and roof area. This is necessary for clear and high-quality implementation of the project and selection required quantity Supplies:
Calculations should begin by choosing the angle of the roof slopes. Optimal slope The angle is considered to be 20-450. The magnitude of the slope must correspond to the climatic characteristics of the region. So, in particularly windy areas, the slope should be kept to a minimum, and for areas where there is frequent and heavy rainfall, the steepest slope angle is necessary. In addition to the weather environment, you also need to consider the roofing material you plan to use. For a soft roof the degree of inclination should be less, for a hard roof it should be greater.
And one more small but important nuance on this issue - it is better to make the slope angle the same for all four slopes. So the load will be distributed evenly, and the structure will be as stable as possible, and the aesthetic appeal will remain “at its best.”
Now, knowing the angle of inclination and the width of the house, we can use simple mathematics to calculate the height of the ridge, the length of the rafter legs, racks and other details of the rafter system. When calculating the length of the rafters, do not forget to take into account the eaves overhang (as a rule, its length is 40-50 cm).
Roof area to purchase the required quantity roofing material is calculated as the sum of the areas of all slopes of the structure.
How to draw a roof drawing correctly?
- We select the scale of the drawing and transfer the dimensions of the house in scale onto a sheet of paper;
- Next, we transfer the selected dimensions of our roof onto the diagram: the height of the ridge, its length, the number and size of rafter legs, struts, racks and all the details, in accordance with the calculations made earlier;
- Now you can count everything necessary materials and start searching for them.
Step II: Preparing for work
For construction roof frame you will need standard tools and equipment: drills, screwdrivers, jigsaws, hammers, chisels, etc. We already know required amount materials for the rafter system, so we can purchase them. The lumber for the frame must be solid, have no cracks, wormholes, have a light shade, without gray or yellow patina, and smell like fresh wood. Wet wood should not be laid on the roof immediately; it must be dried, treated with an antiseptic solution and dried again. Wood humidity should not exceed 20%.
Step III: Mounting the Mauerlat
Mauerlat – basic part the entire rafter system. It transfers thrust loads to load-bearing walls Houses. Installing a Mauerlat for a hipped roof is no different from similar structures with two or one slope. This process is described in as much detail as possible in our previous articles.
The base beam, the parameters of which are described above, is placed on the armored belt and high-quality waterproofing. If it is necessary to connect the Mauerlat, then the bars are cut into half the section and overlapped using strong fasteners.
Step IV: Laying the floor beams or beams
If there are load-bearing walls inside the house, then it is necessary to install beams on their ends - the basis for support posts roofing system. If there are no more load-bearing floors in the house, then the attic floor is covered reinforced beams, on which roof supports are subsequently installed, and then the attic floor pie is laid.
Beams must have a cross-section of at least 100x200 mm. The step between them is 60 cm. You can slightly adjust this figure, depending on the characteristics of your home. The distance between the outer beams and the mauerlat should not be less than 90 cm. This distance is used for installing the half-beams of the eaves overhang (extension). The stems are attached to the two outer beams using strong anchors and reinforced metal corners.
Step V: Installation of support posts, purlins and ridge
Racks are an important part for supporting the structure; they redistribute the weight of the rafter system onto the beams or floor beams. The racks are installed strictly perpendicular to the plane of the bed. In hipped systems, the supports are installed under the ridge beam (hip roof) or under the corner rafters (hipped roof):
The racks must be securely attached to the base using metal plates and reinforced corners. The purlins are installed as additional support for the racks. IN hip roof the purlins are rectangular in shape, and for the hips they are ordinary ridge purlins.
After we have made sure that the supports are installed correctly (using a meter and a level), we can attach the upper ridge beam. It is mounted on vertical posts and reinforced with reliable metal fastenings(plates, corners, anchors and screws). Now let's take on the corner extensions:
Step VI: Installation of rafters
First, you need to install the side rafters, which rest on the ridge beam and the Mauerlat (or are secured with an extension). To do this, you need to make a template rafter with the appropriate cuts. We apply the rafter leg to the ridge, mark the place of the cut with a pencil, then mark the place of the cut of the rafters for joining with the Mauerlat and make cuts. Attach the rafter to the supports again to make sure that the connection is correct and to correct any imperfections. Now this sample can be used to make all the side rafters. Installation of the rafter legs of the main slopes is carried out according to the general rules described in the design of a gable rafter system (see article and video).
Diagonal (corner) rafters are installed next. Their upper edge is installed on the stand and joins the edge of the ridge beam. Before this, measurements are taken and the corresponding cuts of the rafter legs are made. The lower end of the diagonals is fixed in the corners of the Mauerlat:
Since diagonal rafters are longer than all other legs, they require additional support. This function is performed by trusses - support beams that are installed under each diagonal leg, in its lower quarter (this is where the greatest load occurs). Sprengels, like ridge posts, are installed on supporting corner beams located in the plane of the floor beams.
Between the corner ribs the space is filled with auxiliary rafter legs - sprigs. Their lower part rests on the mauerlat, and the upper part rests on the diagonal rafter leg. The step between the frames should be equal to the step between the side rafters (50-150 cm).
Step VII: Sheathing
All that remains is to complete The final stage formation of the roof skeleton - installation of sheathing. These are boards or bars 50x50 mm, which are attached to the rafters parallel to the ridge girder and the mauerlat. The pitch of the sheathing boards is 50-60 cm. This is quite enough for laying the roofing pie. When is it envisaged soft roof, the sheathing is laid in 2 layers (counter-lattice and sheathing).
Finally, a few videos:
So, we described the installation of the rafter system of a hipped roof, its basic principles, and even went a little deeper into some of the nuances. Hip and tent structures are, although not the simplest, but quite feasible options for every novice craftsman. Especially if he has good assistants. We wish you success in your work!
Building a house with your own hands is a long and labor-intensive process, and also very costly in terms of finances. If you wish, you can save on roof installation and do the installation of a 4-pitch roof yourself.
The hip roof is the most popular type of roof, which is also quite easy to construct. with my own hands. If you have at least minimal skills and experience construction work, then, following the instructions, you can build the roof yourself. The choice of a 4-pitch design is explained by its many advantages - effective drainage of rainwater and snow, resistance to wind loads. Under such a roof you can build a spacious attic. The cost of constructing a roof also plays an important role; a 4-pitch roof is a fairly economical option.
Kinds
There are several types of roofs with 4 slopes. The most popular is the so-called hip roof. It consists of two trapezoids and two triangles. Trapezoidal slopes are connected to each other along the upper edge, and triangular ones are connected to them from the front sides.
Another common option is four triangular surfaces connected at one central point. You can also create almost any project that includes slopes at different levels, different shapes, with a broken connection line, etc.
If you are not a construction professional, then when creating a 4-pitch roof, choose a hip roof as it is the easiest to install.
How to make a 4-pitch roof with your own hands. Step-by-step instruction
Before you begin installing the roof, you should draw up a project. You can do the calculations yourself, as there is nothing complicated about it. The main thing is to understand what this or that parameter in the diagram depends on.
Slope angle
When calculating the slope angle of the slopes, three indicators are used:
The slope can be from 5 to 60 degrees. You should also consider whether you will be developing an attic space. If the slopes are too flat, then the height of the attic will be small - it will be impossible to create a living room here. Thus, for the construction of an attic, the slope of the slopes should be no more than 45 degrees.
If the area is characterized by frequent gusty winds or large amounts of precipitation in winter, you should not make a roof with a slope of less than 30 degrees.
If the slope is 60 degrees or more, then the atmospheric phenomena of the climatic zone can be ignored.
As for the roofing material, building codes minimum values are provided for each of them.
- Rolled materials made from bitumen can be laid horizontally.
- Asbestos cement and clay tiles– at an angle of 9 degrees.
- Roofing materials made of steel - slope of 18 degrees or more.
- Wood - from 34 degrees.
Height
The height of the roof is the parameter that will need to be calculated. We know the area of the base since the box is built. The angle of the roof was calculated at the previous stage. Thus, using simple formulas since the times school curriculum, it will be possible to calculate the height of the ridge.
Preparation. Required tools and materials
Prepare all the necessary tools in advance so as not to be distracted by searching for them later. You will need:
- hacksaw
- measuring instruments: plumb line, level and tape measure
- chisel
- circular saw
- drill
- screwdriver
- hammer
Among the materials, the main role is played roofing. Do not forget also about the fasteners with which it will be attached to the rafter system.
For lathing a hipped roof, high-quality lumber is used, larch or pine wood is suitable.
The maximum humidity of boards and beams is 22%.
- For rafters - boards 50 x 100 mm or 50 x 200 mm
- For Mauerlat - timber 150 x 150 mm or more
- Sheathing boards
Also purchase metal threaded studs and metal plates - these elements will be used for fastening. You will also need an antiseptic to pre-treat the wood. To complete the installation of the roof as quickly as possible, prepare the hydro- and thermal insulation material provided for in the project.
Rafter system
- Mauerlat. This is the base of the rafter system, which is made of thick timber. If you are making a roof on log house, then the role of the mauerlat will be played by the last crown of the log house. If the house is brick, then the installation of the Mauerlat is also planned in advance. A concrete belt is made under it, into which metal studs are walled up. The timber is subsequently fixed to them.
- Ridge run. This is the topmost part of the system, thick timber, onto which the rafter boards will subsequently be attached.
- Rafters. These elements are boards from which the main frame is created.
- diagonal rafters connect the corners of the mauerlat and the ridge girder
- row rafters are mounted on trapezoidal slopes
- the rafter half-legs rest on the mauerlat, and on the other side - on the diagonal rafters
- Sill. It is installed parallel to the ridge girder on the load-bearing wall. Its task is to transfer part of the weight of the roof to the frame.
- Support posts. They connect the bed and the ridge girder, making the structure more durable.
- Struts. They rest on the beam and support the diagonal rafters to reduce the load on them.
- Other auxiliary structural elements - truss, tightening, fillies, crossbars. They support certain parts of the sheathing and relieve the load from them.
Stages of frame installation work
- Installation of the Mauerlat and the bench.
- Installation vertical racks in increments of 1000 - 1200 mm.
- Fastening ridge girder.
- Installation of rafter legs. First, one element is made and fitted to the Mauerlat and ridge girder. The rest of the parts are made on its basis. The installation pitch of the rafter legs is 600 or 1200 mm.
- Installation of diagonal rafters. The fastening begins from the top, the boards are cut into the ridge so that they become its continuation. They are attached from below in the corners of the Mauerlat.
- Fastening of sprigs.
- Installation of struts and trusses. These elements are not always necessary. If the structure is strong enough without them, then there is no need for installation.
Additional elements are required if the length of the rafters is 6 meters or more. In other cases - at your discretion.
- Installation of waterproofing. The selected material is fastened using a construction stapler.
- Sheathing flooring. If it is continuous, regular one will do plywood. Boards are used for the lattice frame.
- Laying roofing material. Fastening is carried out exclusively in a way that is suitable for the specifically selected building material. It is best to use the fasteners included in the kit.
- Installation of a drainage system. This is the final part of the roof installation work.
If attic space If you plan to use it as a residential attic, you need to insulate it from the inside. Then all that remains is to carry out Finishing work– and the roof is ready for use both outside and inside.
- If you are not confident in your own knowledge, you can order a hip roof project from professionals. It is often done at the same time as the house project. In any case, it will cost less than restoring the roof after installation according to incorrect parameters.
- If you know computer programs, you can create a roof layout in 3D projection.
- Don't skimp on materials. Before installation, carefully check all boards for strength and treat them with an antiseptic. There should be no cracks, bends or irregularities on the elements. For the rafter system, materials of grade 1 and higher are used.
- Before installing the Mauerlat, the surface of the walls can be covered with roofing felt.
- The Mauerlat must be fastened very firmly so that it does not move even a fraction of a millimeter during operation. This is the basis of the entire rafter system, on which the strength of the roof depends.
- Compound rafter elements between themselves is carried out using metal corners, which are firmly attached to the connected elements with bolts.
Thus, it is quite possible to make a hipped hip roof with your own hands if you have at least basic construction skills. All you need is careful preparation, studying the theory and drawing up a detailed project with calculation of the amount of materials needed.
An example of the construction of a hip roof can be seen in the following video:
The classic hipped roof, even today, remains unusual for Russian latitudes and is reminiscent of the overseas way of life. That is why it is most often built in order to give the architecture of a residential building a special effect in terms of style and perception, it is advantageous to distinguish it from monotonous, familiar buildings.
In addition, a hipped roof - built with your own hands according to all the rules - in practice has a large number of advantages, especially for the harsh Russian latitudes. Let's take a closer look?
A hipped roof has slopes that are made in the form of isosceles triangles and their vertices converge at one point. If the hipped roof is square in plan when viewed from above, then it is called a hip roof.
If it doesn’t turn out square, but turns out to be a rectangle, it’s a hip roof. It received such an interesting name thanks to the stingrays, which have the appearance of a gable hip.
Dutch roof: classic four slopes
The Dutch or hip roof is considered a classic option, which is particularly resistant to wind and snow.
The surface of a standard hip roof forms two trapezoidal slopes on the long sides and the same number of triangular ones on the short sides. Unlike a hip roof, this form, according to modern architects are considered more aesthetic.
It involves the installation of four rafters - diagonal support beams that run from the two tops of the slopes to the upper corners of the building.
But the half-hip roof, in turn, comes in two types: when the side slopes cut off only part of the end at the top, or already at the bottom, that is, the half-hip itself can be a triangle or a trapezoid, and is called Danish or half-hip Dutch.
Half-hip Dutch roof: particularly stable
The half-hip Dutch roof is both an option and gable design, and hipped. It's different from classic version the presence of truncated hips - triangular end slopes. According to the rules, the length of the hip of a Dutch roof should be 1.5-3 times less than the length of the side trapezoidal slopes.
The advantage of such a roof is that it is possible to install a vertical dormer window, and at the same time there is no sharp projection, like a gable roof, which, in turn, increases the roof’s ability to withstand extreme wind loads.
Half-hip Danish roof: European traditions
But the Danish half-hip roof is a type of purely hip roof. In this case, only the lower part of the end slope is mounted, and a small vertical pediment is left under the ridge.
The advantage of this design is that it allows you to avoid problems with waterproofing. skylights in the roof and provide daylight attics due to the installation of full vertical glazing, which is especially fashionable now.
Hip roof: ideal proportions
A hip roof is usually installed on buildings that have the same length of walls, which form a square perimeter. In such a hipped roof, all the slopes are shaped like identical isosceles triangles, a roofer’s dream, in a word, and a builder’s nightmare.
The fact is that the construction of a classic hip roof is even more difficult than that of a hip roof, because here the rafters must all converge at one point: 
Construction of a roof truss system with four slopes
Here is the simplest example of building a standard hip roof for a small country house:
Stage I. Planning and design
Before making a hipped roof, be sure to think through all its details, down to the smallest detail. Be sure to build even the simplest hip roof structure according to a ready-made drawing. The fact is that the finished gable roof has almost noticeable defects and distortions, but if you make a mistake somewhere in the construction of the same hip or hip roof, then the diagonal rafters simply will not meet at the ridge and it will be extremely difficult to correct this.
Therefore, if you know special programs, create a 3D model of the future roof directly in them, and if not, then just prepare detailed drawing and it’s good if a professional helps you with this. All the details of such a roof must be calculated - down to the smallest detail!
By the way, today it is quite fashionable to make not only the roof hipped, but also its individual functional elements:
Stage II. Preparation of structural elements
So if you took finished drawing roofs or have sketched it yourself and are confident in the future quality, it’s time to prepare the necessary elements of the rafter system. And to do this, first let’s figure out how they are called correctly.
So, the first thing you have to take care of before building a hip roof is Mauerlat. This is a square beam or rectangular section, which you will lay on the top of the walls around the entire perimeter of the house. It will become a support for the rafters, which will transfer the load to it, and it is this board that will evenly distribute the weight of the entire roof onto the walls of the house and the foundation. Perfect option– use a beam with a section of 15 by 10 cm as a mauerlat.
Next you will build rafter legs- this is the main element that will create the roof slope. Standard rafters are made from boards 50 by 150 mm, and diagonal ones - 100 by 150 mm.
You will also need puffs, the main task of which is to prevent the rafter legs from moving to the sides. You will fix the puffs themselves and connect them with the lower ends, and for this, stock up on boards measuring 50 by 150 meters.
But from above, both the diagonal rafter legs and the standard rafters will converge and be secured to each other in skate. To do this, take a beam 150 by 100 mm.
Next, in the center of two opposite sides there should be cross beam – sill, which serves as a support for the racks, and they, in turn, support the ridge girder. A timber with a cross section of 100 by 100 mm or 100 by 150 mm is suitable for this purpose.
Slopes will become a support for the rafters, which prevents them from moving. You should install them at an angle to the stand; to do this, take the same material as for the bench.
Don't forget also about wind board- this is a horizontal element that connects all the lower ends of the rafters. You will need to nail it to the rafters along the inner perimeter of the roof and in this way emphasize the line of the slope. A 100 by 50 mm board is suitable for this purpose.
But for outside you will need one more board - filly, from the same material. This board received such a strange name from the times when it was carved in the form of horse faces.
But the most unusual and complex element of a hipped roof is truss, which gives rigidity to the entire structure. Its main task is to connect all horizontal and vertical elements. It is also mounted at an angle, and is made of 100 by 100 mm timber:
And finally, if we are talking specifically about a hip roof, then the only element that is present exclusively in hip roofs is narozhniki. They are shortened rafters that rest on a diagonal rafter leg. You can make them from a 50 by 150 mm board.
In life, all these elements look like this:
Also think about insulation, waterproofing film and additional roofing elements:
Stage III. Installation of attic floor
Often the headstocks of hanging rafters or hangers, which work in tension in a hip roof, must be made of steel. To do this, special wooden purlins are suspended perpendicularly to the clamps of the wooden rafters.
And they are already suspended perpendicular to the purlins wooden beams, after which beamless lightweight fillings are laid between them. Therefore, if you want to reduce the roof load on the hanging rafters or roof truss, you need to choose suspended floor structures.
For steel trusses, the suspended ceiling must be made fireproof, using steel beams. Between such beams, prefabricated reinforced concrete slabs, and already on them - lightweight insulation. To increase the fire resistance and durability of such load-bearing structures, they must be made of reinforced concrete. Moreover, the most reinforced concrete bearing structures It is better to make it from large-sized factory-made panels so as not to take risks.
Stage IV. Installation of ridge girder
When calculating the ridge run, take into account the following nuances:
- If the building has permanent longitudinal walls, or at least two rows of internal pillars, then two purlins are made. At the same time, many rafter structures can be composite along their length, and crossbars are used to increase rigidity.
- If the building does not have internal supports, then it will not be possible to make inclined rafters here. And therefore special construction trusses are used, to which attic floor it simply hangs up. In this case, the rods, which are located along the upper contour of the trusses, form the upper chord of the construction truss, and along the lower contour - the lower chord. The truss lattice itself now forms vertical rods and braces - inclined rods that are located between the upper and lower chords. Moreover, such trusses are not necessarily made only of wood; on the contrary, steel reinforced concrete ones are quite popular today. During the construction process, the trusses are installed at a distance of 4-6 meters from each other. The simplest version of such trusses are truss trusses, which consist of rafter legs, a vertical suspension, headstock and tie rods.
- If the width of the building is large enough, construction trusses or truss supports are used during installation. But then the attic floor cannot be covered with beams that will rest on the walls alone. Such a structure must be suspended on steel clamps to the lower chord of the truss, or to a tie, in order to thus form suspended ceilings.
This photo illustration clearly shows exactly how the rafters need to be attached to the ridge and ridges:
Stage V. Installation of standard and diagonal rafters
So, the diagonal rafter legs rest directly on the ridge, depending on the following conditions:
- If there is only one ridge girder in the middle of the roof, then the diagonal leg must be placed on the girder console. They are specially produced for this purpose 15 centimeters behind the fake frame, and then the excess is sawed off.
- If there are two purlins, then you need to install a truss structure of a horizontal beam and a rack on them, and then secure the slanted rafters themselves.
- If the beam is strong, made of timber, and not of boards, then it makes sense to make a break - a short board at least 5 centimeters thick. And the slanted rafters of the hip roof should be supported on it.
Additionally, for reliability, the slanted rafters are secured with metal wire twisted several times.
On the ribs, the installation of ridge elements must be done in the same sequence as on a regular roof ridge. Those. set the rib element with closed end, place the ridge elements in the lock and secure them mechanically. But at the intersection of the ribs and the ridge of a hip roof, it is customary to install Y-shaped ridge elements, although starting and ending ridge elements can also be used instead.
But only cut them along the contour when they are secured to the edge, and mechanically secure the joints. Be sure to treat with primer and mineral coating from the standard repair kit. Also, when installing ridge elements, do not forget to leave a gap on the ribs or ridges of a hipped roof to allow air to escape from the under-roof space.
All the same principles must be observed when building a hipped roof of complex shape:
You can do it! Please ask your questions in the comments.
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The hip (hipped) roof gives the house a sophisticated look. The special design of the roof makes it possible to additionally protect the structure itself and its walls from moisture. Therefore, building a roof with four slopes is optimal for regions with high rainfall and strong winds.
Stages of building a hipped roof
The first stage of building a roof is determining the purpose of the roof (covers the attic floor, attic, etc.), choosing the roofing material (depending on this, the list of materials for construction will be determined), taking into account the atmospheric conditions of the place where the roof will be used (wind, rain , snow).
Choosing a hip roof will give the building greater resistance to rain and make it more durable (the rafter system is more reliable). The main difference between this type of roof and a gable roof is that instead of side gables, it has two triangular roof slopes.
When choosing the angle of inclination of the slopes, you should take into account the level of precipitation and wind characteristics of the area. For low and medium annual precipitation, it is recommended to choose an angle within 4-40 degrees. In case of heavy snowfalls and prolonged rains, the recommended optimal angle of inclination of the slopes is within 40-60 degrees.
The roofing material can be: roll roofing, tiles or metal tiles.
Depending on all the above nuances, the thickness and other parameters of the wooden component of the hipped roof will be selected.
The end result of the first stage is the creation of a diagram of the future roof, on the basis of which construction will be carried out.
We will describe further technology on how to make a hipped roof with your own hands.
The second stage is to build the base for the roof. The base is used to evenly distribute the load from the roof to the load-bearing walls. The construction of a hipped roof requires a base that can be built on your own - a wooden mauerlat and beds. Waterproofing is required under the base to extend the service life of the roof. A mauerlat is placed on the hydraulic barrier along the outer contour of the building (the size of this beam varies, either 100x150 mm, or 50x150 mm).
Lezhni - a beam located in the plane of the base of the rafter system at the same distance from the two side mauerlats. It serves as a supporting element for struts and racks, so it is laid on load-bearing partitions (see drawings of a hipped roof). Large roof structures may include several roof decks.
The third stage involves the direct installation of the roof frame (base, rafters, sheathing).
Structurally, the construction of a roof in a house with or without existing floors differs (in this case there is no need to lay floor beams on which supports will be installed).
The installation of racks (vertical supports of the roof frame) should be approached with particular care. It is necessary to accurately maintain the installation angle (90 degrees). At the slightest deviation, further deformation of the roof is possible. The installation pitch of the racks is up to two meters.
The structure of a hipped roof of a house consists of four planes (slopes). Two trapezoidal and two triangular. Trapezoidal slopes will be formed by side rafters, hip (triangular) slopes - by slanted (diagonal) rafters.
The rafters at the top of the frame are supported in the ridge beam (purlin). This beam goes on top of the vertical posts (possibly a groove connection with the posts). The distance between the rafters is from 50 to 150 cm (according to the roof plan). The recommended width of the rafter board is 150 mm.
The frame is fastened using corners and steel plates with self-tapping screws (nails). To strengthen the resulting structure, diagonal supports, struts, and wind beams are used. They allow you to increase permissible load systems.
Waterproofing is laid on top of the rafters. Then a counter-lattice is made (bars that are attached to the rafters on top of the waterproofing). It is needed to create a ventilation channel between the roofing material, sheathing and waterproofing. This will allow moisture to be removed quickly and effectively. Next, the sheathing is performed - horizontal boards are attached from the bottom to the very top to the counter-lattice (see diagram of the hipped roof structure).
The last step is the installation of roofing material. Installation is carried out depending on the parameters of the material. Example.
In private housing construction, in addition to the common gable roofs Stronger and more rigid hipped structures are often used. They are distinguished by the absence of pediments, which replace triangular slopes that cut off the ends of the ridge ridge. This configuration makes hipped roofs very attractive and economical, despite the fact that their construction increases the length of the eaves overhangs, the number drainpipes and gutters. Therefore, they deserve the closest attention.
Types of rafter systems for hipped roofs
The design of the rafter system depends on the shape of the hipped roof. The most common configurations today are:
- Hip structure. All four slopes occupy the area from the ridge to the eaves overhang, while the two side ones have trapezoidal shape, and the two end ones (hips) are triangular. Feature of the rafter hip frame is the presence of two pairs of diagonally installed rafters, which extend from the edge of the ridge and serve as supports for the trusses and trusses.
The hip hipped design is characterized by the fact that the slopes occupy the entire roof area - from the ridge to the eaves
- Dutch half hip. A device with truncated end slopes that do not reach the cornice. As a rule, they are 2–3 times smaller than trapezoidal ones. The advantage of this hipped roof structure is the possibility of installation at the ends of the house regular window, as well as the absence of a sharp projection typical of gable roofs, which greatly increases the wind resistance of the structure.
The Dutch half-hip roof has truncated triangular slopes and part of the pediment into which a regular vertical window can be installed
- Danish half hip. It is characterized by the presence of a pediment at the ridge in the triangular slopes, which allows for full natural lighting of the under-roof space without installing roof windows.
- Tent structure. Installed on houses with a square frame. All four slopes of the hipped roof are identical isosceles triangles connected at one point. When constructing such a roof important aspect is to maintain symmetry.
The structure of the hip truss system depends on the selected roof configuration
Features of the supporting frame of a hipped roof
Let us immediately note that the rafter system of a hipped roof will be more complex compared to traditional gable structures for two reasons.
- Due to the increase in the number of inclined planes and their joining to each other. At its core, the connection of slopes is intersection lines running at a certain angle to the horizon. The joints that form an angle protruding above the surface of the slopes are called roof ribs. From them, water flows down the slopes and accumulates in grooves (valleys) - lines of intersection with the internal corner. If all planes have the same slope, then the ribs and valleys divide the angle of the base at the junction of adjacent slopes in two and create a slope to the perimeter of the building of 45°.
Four-slope rafter systems are distinguished by the absence of full pediments, instead of which there are two triangular end slopes, as well as the presence of two lateral trapezoidal inclined planes, grooves and ribs
- Due to the fact that the purlins in a hipped structure form closed loop, where the hip (diagonal) rafter legs are located along the lines of the ribs and valleys. They are longer than ordinary beams, which are installed longitudinally along the slopes at a distance between intersections hip rafters in the top harness. But between the lower parts of the diagonal legs, short rafters, called sprigs, are mounted. A distinctive feature of the frame of a hipped roof is the presence of trusses - wooden struts under the hip rafters.
Support purlins in hipped structures have a closed contour, where diagonal rafter legs are located along the lines of valleys and ribs
Main structural elements rafter system of a hipped roof are:
Thus, the number of elements of the rafter system of a hipped roof is much greater than, for example, that of a gable roof, and this, naturally, increases the cost of its construction. However, in general, as we noted above, the installation of a hipped roof will not cost much more due to the savings on laying the roofing pie, since waste insulating materials and the covering flooring when cutting into a multi-slope structure will be significantly less.
Despite the fact that the rafter system of the hipped structure is more complex and expensive, the construction of the entire roof is more profitable due to the savings on arranging the roofing pie
In addition, the hipped design:
Video: gable or hip roof - what to choose
How to calculate the rafter system of a hipped roof
The supporting structure of a hipped roof can be layered if the structure has permanent internal walls, or hanging when intermediate supports are not provided in the structure. With a hanging structure, the rafters rest on the walls of the house and exert a bursting force on them. To relieve the load on the walls in such cases, a tie is installed at the base of the rafter legs, connecting the rafters to each other.
The use of a layered structure makes the frame lighter and more economical due to the fact that less lumber is required for its arrangement. Because of this, the layered rafter system is used much more often in the construction of multi-pitched roofs. But regardless of the type of rafters used, only correct calculation supporting frame and precise marking will increase the economic effect of erecting a hipped structure.
Marking and calculation of the supporting frame of a hipped roof
When calculating the rafter system, you must adhere to the following rules.
To determine the installation location of the rafters and find their length, you will need a template.
Using a template will make it much easier to measure and calculate the rafter frame of a hipped roof
The length of the rafter leg can be determined by its position (horizontal projection). There is a special table of coefficients for this, presented below. The length of the rafter is determined by the size of its projection, multiplied by a coefficient corresponding to the slope of the slope.
Table: relationship between the length and laying of the rafters
| Roof slope | Coefficient for calculating the length of intermediate rafters | Coefficient for calculating the length of corner rafters |
| 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 |
| Note: when constructing a roof frame for which there is no data in the table (for non-standard slopes), the parameters should be calculated using the Pythagorean theorem or using a mathematical proportion. | ||
Let's look at an example: under construction a private house in Yekaterinburg measuring 7.5x12 m with a planned height of the hip roof made of metal tiles of 2.7 m.
- First of all, we draw a drawing or sketch of the roof.
Before calculating the rafter system, it is necessary to make a sketch of the building and apply all the initial data to it
- We find the angle of inclination of the slopes using the formula: the tangent of the angle of inclination is equal to the ratio of the height of the roof to half the length of the span, in our case - to half the end side L = 7.5 / 2 = 3.75. Thus, tan α = 2.7 / 3.75 = 0.72. Using reference tables, we determine: α = 36°, which corresponds to the standards requiring a roof slope for metal tiles of at least 14°, and the climatic conditions of Yekaterinburg.
The tangent of the angle of inclination of the slopes is determined by the well-known formula for calculating the sides of a right triangle as the ratio of the opposite side to the adjacent one
- We determine the position and edge of the ridge ridge, for which we apply the template at an angle of 36° in the middle top harness end (place of installation of the first central intermediate rafter) to a height of 2.7 m and design the outline on the sketch.
- We retreat ½ the thickness of the ridge beam from the center (key) line and install the end of the measuring rod at this point. At the other end of the slats, we make marks for the outer and inner contours of the side wall, as well as the overhang. Turn the rack to the side and away from internal corner of the external trim, we mark the location of the intermediate rafter along the mark of the internal contour, thus determining the installation location of the second intermediate central rafter.
When arranging the rafter frame of a hipped roof, the position of the central rafter legs is initially determined using a template and a measuring rod
- We carry out similar actions at all corners, determining the edges of the ridge ridge and the location of all central rafter legs.
- After planning the intermediate rafters, we determine their length from the table. In our example, the tilt angle is 36°, its tangent is 0.72, which corresponds to a ratio of 8.64:12. There is no such value in the table, so let’s calculate the coefficient relative to the line with the parameter 8:12 - 8.64/ 8 = 1.08. This means that the required coefficient is 1.202 · 1.08 = 1.298.
- By multiplying the depth of the intermediate rafters by the calculated coefficient, we find their length. Let us take into account the laying depth of 3 m, then L str = 3 · 1.298 = 3.89 m.
The length of the row and central intermediate rafters depends on the angle of the roof and the depth of their laying
- Similarly, we determine the length of the diagonal rafters, having previously calculated the laying equal to the distance from the corner of the connection of the side and end slopes to the first intermediate central rafter. According to the initial data, the position of the corner rafters is 7.5 / 2 = 3.75 m. Then the estimated length of the corner rafters will be equal to 3.75 1.298 = 4.87 m.
Corner rafters are different from intermediate device undercuts with a double bevel in the ridge area, deeper laying and longer undercut lengths for the supporting part
- We calculate the overhang using the Pythagorean theorem according to the markings made or simply add the desired size to the length of the rafters, for example, 0.6 m plus at least 0.3 m for arranging an external drain.
To calculate the length of the overhang, you need to multiply its position by the coefficient for the intermediate or corner rafters or to effective length rafters add the planned overhang length and at least 0.3 m to organize an external drainage system
- Having marked all the elements of the rafter frame, we determine the length of the ridge ridge, which is equal to the difference between the length of the side and the doubled value of the intermediate rafters: 12 – 2 3 = 6 m. It is at this distance that the ordinary rafters will be installed. If we take a step of 1 m, then we will need 5 row rafters, equal in length to the central ones. In addition, in the area where the intermediate central rafters are laid, which is 3 m long, two short rafters will be installed on one and the other side edge.
- Since the short rafters (springs) are attached to the diagonal ones, it means that end sides Between the corner and central intermediate rafters there will also be two flanges installed on the left and right.
Let's summarize - for the rafter frame of a hipped roof you will need:
- two pairs of hip (corner) rafters with a length of 4.87 + 0.6 + 0.3 = 5.77 m;
- three pairs of intermediate central rafters with a length of 3.89 + 0.6 + 0.3 = 4.79 m;
- five pairs of ordinary rafters 4.79 m long.
There are only ten pairs of rafters, the total length of which will be approximately 100 linear meters. We add here 6 m for the ridge beam, as well as a ten percent margin, and we get that approximately 117 linear meters of lumber are needed to make a simple hip rafter frame with struts, spacers, crossbars, trusses and fillets. But if the design includes racks and a bench, then they will have to be calculated separately or a larger percentage of the margin should be added.
Video: hip roof rafter system, installation technology
https://youtube.com/watch?v=n_Yr2QB3diMThe measuring rod greatly facilitates the work and helps to avoid gross errors when taking measurements. It is most often made independently from plywood 50 mm wide.
A few words need to be said about short rafters. They are calculated in the same way as intermediate ones: the laying multiplied by the coefficient for intermediate rafters from the table. However, the task can be simplified and you don’t have to specifically calculate the length of the spigots, since a sufficient percentage of the margin is taken, and the trimmings of the boards will be needed for the manufacture of elements reinforcing the structure - struts, spacers, crossbars, etc.
The length of short rafters (springs) can not be calculated, since scraps of lumber will be useful for the manufacture of reinforcing structural elements
Video: rafter frame of a hip roof, marking of elements and assembly
Calculation of lumber cross-section
After marking the position of the components of the rafter frame, it is necessary to select suitable lumber, i.e., determine their permissible cross-section. For calculations, you will need a zoned map of snow and wind loads and thermal resistance, as well as auxiliary tables based on regulations- SNiP II-3–79, SP 64.13330.2011, SNiP 2.01.07–85 and SP 20.13330.2011.
The installation of a hipped roof includes the determination of the required cross-section of lumber, which is carried out based on an analysis of the loads on the truss structure during operation
The load from snow cover is determined by the formula S = S g µ, where S is the desired snow load (kg/m²); S g is the standard load for the real area, indicated on the map, µ is a correction factor depending on the slope of the roof. Since our tilt angle ranges from 30 to 60°, we calculate µ using the formula 0.033 · (60 – 36) = 0.792 (see note to the table below). Then S = 168 · 0.792 = 133 kg/m² (Ekaterinburg is located in the fourth climatic region, where S g = 168 kg/m2).
Table: determination of the µ indicator depending on the roof slope
| Determining the angle of the roof | |
| Tangent value | Angle α° |
| 0,27 | 15 |
| 0,36 | 20 |
| 0,47 | 25 |
| 0,58 | 30 |
| 0,7 | 35 |
| 0,84 | 40 |
| 1 | 45 |
| 1,2 | 50 |
| 1,4 | 55 |
| 1,73 | 60 |
| 2,14 | 65 |
| Note: if the slope angle (α) ≤ 30°, then the coefficient µ is taken as 1; if angle α ≥ 60°, then µ = 0; if 30°< α < 60°, µ высчитывают по формуле µ = 0,033 · (60 - α). |
|
Table: standard snow loads by region
| Region No. | I | II | III | IV | V | VI | VII | VIII |
| S g, kg/m 2 | 56 | 84 | 126 | 168 | 224 | 280 | 336 | 393 |
We calculate the wind load using the formula W = W o k c, where W o - standard indicator according to the map, k is a tabular index, c is the aerodynamic drag coefficient, varying from -1.8 to +0.8 and depending on the slope of the slopes. If the angle of inclination is more than 30°, then according to SNiP 2.01.07–85 clause 6.6, the maximum positive value of the aerodynamic index, equal to 0.8, is taken into account.
Yekaterinburg belongs to the first zone in terms of wind load, the house is being built in one of the city districts, the height of the building including the roof is 8.7 m (zone “B” according to the table below), which means W o = 32 kg/m², k = 0 .65 and c = 0.8. Then W = 32 · 0.65 · 0.8 = 16.64 ≈ 17 kg/m². In other words, it is with this force that the wind at a height of 8.7 m presses on the roof.
Table: k index value for different types of terrain
| Building height Z, m | Coefficient k for terrain types | ||
| A | IN | WITH | |
| ≤ 5 | 0,75 | 0,5 | 0,4 |
| 10 | 1,0 | 0,65 | 0,4 |
| 20 | 1,25 | 0,85 | 0,55 |
| 40 | 1,5 | 1,1 | 0,8 |
| 60 | 1,7 | 1,3 | 1,0 |
| 80 | 1,85 | 1,45 | 1,15 |
| 100 | 2,0 | 1,6 | 1,25 |
| 150 | 2,25 | 1,9 | 1,55 |
| 200 | 2,45 | 2,1 | 1,8 |
| 250 | 2,65 | 2,3 | 2,0 |
| 300 | 2,75 | 2,5 | 2,2 |
| 350 | 2,75 | 2,75 | 2,35 |
| ≥480 | 2,75 | 2,75 | 2,75 |
| Note: “A” - open coasts of seas, lakes and reservoirs, as well as deserts, steppes, forest-steppes, tundra; “B” - urban areas, forests and other areas evenly covered with obstacles more than 10 m high; “C” - urban areas with buildings over 25 m high. |
|||
Table: standard wind load by region
| Region No. | Ia | I | II | III | IV | V | VI | VII |
| W o , kg/m 2 | 24 | 32 | 42 | 53 | 67 | 84 | 100 | 120 |
Now let's calculate the load on the supporting frame from the weight of the roof. To do this, add up the weight of all the layers of the roofing pie laid on top of the rafters. We leave the rafters open to reach decorative effect, which means we lay all the layers on top of the rafters. The roof load on the elements of the rafter system will be equal to the sum of the weights of the metal tiles, sheathing and counter-lattens, insulating films, insulation, additional sheathing and ventilation slats, a solid plywood base and facing material under-roof room.
When determining the load on the supporting frame from the weight of the roof, the weights of all layers of the roofing cake laid on top of the rafters are summed up
The mass of each layer can be found in the manufacturer's instructions by selecting the highest density value. We calculate the thickness of the heat insulator using a thermal resistance map for a specific area. We find it using the formula T = R λ P, where:
- T is the thickness of the heat insulator;
- R is the thermal resistance standard for a specific area, according to the map included in SNiP II-3–79, in our case 5.2 m 2 °C/W;
- λ is the thermal conductivity coefficient of the insulation, which for low-rise construction is taken equal to 0.04;
- P - highest density value thermal insulation material. We will use basalt insulation"Rocklight", for which P = 40 kg/m².
So, T = 5.2 · 0.04 · 40 = 8.32 ≈ 9 kg/m². Thus, the total load of the roof will be equal to 5 (metal tiles) + 4 (solid flooring) + 23 (main, additional and counter lathing) + 0.3 2 (insulating films) + 9 (insulation) + 3 (cladding) = 44 .6 ≈ 45 kg/m².
Having received all the necessary intermediate values, we determine the total load on the supporting frame of the hipped roof: Q = 133 + 17 + 45 = 195 kg/m².
The permissible cross-section of lumber is calculated using the formulas:
- H ≥ 9.5 · L max · √, if angle α > 30°;
- H ≥ 8.6 L max √, if α< 30°.
The following notations are used here:
- H - board width (cm);
- L max - maximum working length of rafters (m). Since the layered rafter legs are connected in the ridge area, the entire length is considered working and L max = 4.79 m;
- R bend is an indicator of the bending resistance of wood (kg/cm). According to the set of rules 64.13330.2011 for wood of grade II R bend = 130 kg/cm;
- B is the thickness of the board, taken arbitrarily. Let's assume B = 5 cm;
- Q r - load per linear meter of one rafter leg (kg/m). Qr = A · Q, where A is the pitch of the rafters, which in our case is 1 m. Therefore, Q r = 195 kg/m.
Substitute the numerical values into the formula → H ≥ 9.5 · 4.79 · √ = 9.5 · 4.79 · 0.55 = 25.03 cm ≈ 250 mm.
Table: nominal sizes of softwood edged boards
| Board thickness, mm | Width (H) of boards, mm | ||||||||
| 16 | 75 | 100 | 125 | 150 | - | - | - | - | - |
| 19 | 75 | 100 | 125 | 150 | 175 | - | - | - | - |
| 22 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | - | - |
| 25 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 32 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 40 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 44 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 50 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 60 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 75 | 75 | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 100 | - | 100 | 125 | 150 | 175 | 200 | 225 | 250 | 275 |
| 125 | - | - | 125 | 150 | 175 | 200 | 225 | 250 | - |
| 150 | - | - | - | 150 | 175 | 200 | 225 | 250 | - |
| 175 | - | - | - | - | 175 | 200 | 225 | 250 | - |
| 200 | - | - | - | - | - | 200 | 225 | 250 | - |
| 250 | - | - | - | - | - | - | - | 250 | - |
From the table, the thickness of the board with a width of 250 mm can vary from 25 to 250 mm. A table of the dependence of the cross-section on the pitch and length of the rafters will help you determine more specifically. The length of the intermediate rafters is 4.79 m, pitch 1.0 m - look at the table and select the appropriate section. It is equal to 75X250 mm.
Table: cross-section of lumber depending on the length and pitch of the rafters
| Rafter spacing, cm | Rafter length, m | ||||||
| 3,0 | 3,5 | 4,0 | 4,5 | 5,0 | 5,5 | 6,0 | |
| 215 | 100Х150 | 100Х175 | 100Х200 | 100Х200 | 100Х200 | 100Х250 | - |
| 175 | 75Х150 | 75Х200 | 75Х200 | 100Х200 | 100Х200 | 100Х200 | 100Х250 |
| 140 | 75Х125 | 75Х175 | 75Х200 | 75Х200 | 75Х200 | 100Х200 | 100Х200 |
| 110 | 75Х150 | 75Х150 | 75Х175 | 75Х175 | 75Х200 | 75Х200 | 100Х200 |
| 90 | 50Х150 | 50Х175 | 50Х200 | 75Х175 | 75Х175 | 75Х250 | 75Х200 |
| 60 | 40Х150 | 40Х175 | 50Х150 | 50Х150 | 50Х175 | 50Х200 | 50Х200 |
Let's give another table for those who will use hardwood lumber.
Table: maximum deviations from the nominal dimensions of the boards
We check the correctness of the calculations by substituting the numerical parameters into the following inequality / ≤ 1. We get (3.125 · 195 x 4.79³) / (7.5 x 25³) = 0.57 - the cross section is selected accurately and with a good margin. Let's check less powerful beams with a section of 50x250 mm. We substitute the values again: (3.125 · 195 x 4.79³) / (5 x 25³) = 0.86. The inequality is satisfied again, so a beam measuring 50x250 mm is quite suitable for our roof.
Video: calculation of the hip roof rafter system
After all the intermediate calculations, we summarize: to erect the roof we will need 117 linear meters of edged boards with a section of 50X250 mm. This is approximately 1.5 m³. Since it was initially agreed that for a four-slope hip structure it was desirable to use lumber of the same section, then for the mauerlat the same timber should be purchased in an amount equal to the perimeter of the house - 7.5 2 + 12 2 = 39 linear meters. m. Taking into account a 10% margin for cutting and scrap, we get 43 linear meters or approximately 0.54 m³. Thus, we will need approximately 2 m³ of lumber with a section of 50X250 mm.
The length of the rafters is the interval from the cut for the supporting part to the cut for the ridge beam.
Video: example of roof calculation using an online calculator
Rafter system installation technology
The arrangement of a hipped structure has its own characteristics that must be taken into account:
Manufactured and assembled in compliance with all the rules, a layered rafter frame for a hipped roof will be a non-thrust structure. You can prevent the appearance of thrusts if the planes of the rafters are made horizontal in places where they support the Mauerlat.
In most cases, two schemes are used to support the rafter legs.
In hip hip structures, the length of the corner legs is often longer than the typical length of the lumber. Therefore, the beams and boards are spliced, trying to place the joints at a distance of 0.15 span lengths (L) from the center of the supports, which is approximately equivalent to the interval between the support points. The rafters are connected using the oblique cutting method, tightening the joints with bolts Ø12–14 mm. It is recommended to make the cut on the rafters, and not on the support beam, so that the cut does not weaken the support.
Since the standard length of most lumber does not exceed 6 m, diagonal rafters are increased in length using the oblique cutting method and connected with bolts when using timber or with nails and clamps if boards are spliced
Table: position of supports for corner rafters
| Span length, m | Types of supports | Location of supports |
| less than 7.5 | stand or strut | at the top of the rafters |
| less than 9.0 | stand or strut | at the top of the rafters |
| truss or stand | at the bottom of the rafters - 1/4L inc. | |
| over 9.0 | stand or strut | at the top of the rafters at the bottom of the rafters - 1/4L pr |
| truss or stand | in the center of the rafters | |
| rack | in the center of the rafters | |
| Note: Lpr is the length of the span, which is covered by rafters. | ||
To connect the frames to the rafters, the top of the half-rafters is ground off, keeping them in the same plane as the corner legs, and secured with nails. When placing sprigs on the rafters, make sure that they do not converge in one place. If you use 50X50 mm cranial bars, packed in the lower zone of the rafters on both sides, rather than a notch when installing the rafters, then the rigidity of the rafter legs will be higher, which means their load-bearing capacity will increase.
To increase the rigidity of the rafter frame, it is recommended to use cranial bars stuffed on both sides at the bottom of the rafter legs when installing the rafters.
Do-it-yourself installation of a truss structure
The construction of the frame of a hipped roof is carried out in several stages.
- The materials are marked and calculated, after which roofing felt is laid as waterproofing along the entire perimeter of the building. A support for the racks and a Mauerlat are placed on top of it, securing it to the walls, fixing it especially well in the corners.
The Mauerlat in hipped structures is laid around the entire perimeter and is well secured to the walls, especially in the corners, to create a strong unit for attaching diagonal rafters
- A frame for the ridge girder is installed and the girder itself is laid, strictly maintaining the height and spatial arrangement of the ridge, since the strength and reliability of the entire rafter structure directly depends on this.
- Place the support posts using a water level for leveling and secure them under the ridge with inclined supports. The placement of racks is done based on the configuration of the roof - in a hip structure, the racks are installed in one row with an interval of no more than two meters, and in hip roof- diagonally at the same distance from the corner.
- The central intermediate rafters are mounted, and then the ordinary ones, filling the middle of the side slopes.
- According to the markings, corner rafters are installed, preferably made with reinforcement, resting their lower part on the corner of the Mauerlat, and their upper fragment on the stand. The installation of the eaves overhang and drainage is also done here.
- Next, half-rafters (springs) are placed, strengthening the lower part of the diagonal legs with trusses, which will partially relieve the corner rafters, and they are sheathed along the perimeter of the roof with a wind board.
Truss grating is used for steep roofs and relatively large spans in order to avoid deflection of diagonal rafters
- After installation of the rafter system, the roofing pie is laid, the eaves overhangs and drainage system are installed.
When installing the rafter system of a hipped roof, you need to carefully consider the joining of the diagonal rafters, the central rafter at the end of the building, as well as the ridge beam
Video: hipped roof on nails and stool
Self-construction a hipped roof is, of course, not an easy process. But if you have measuring instruments, as well as the necessary tools, you will succeed. The main thing is the desire to assemble the structure with your own hands and the desire to adhere to general principles. And in order for the roof to last as long as possible and maintain its amazingly beautiful appearance, try not to skimp on the elements of the rafter frame and use modern reliable metal fasteners for wood to fix them.