Friends, we hope that this information will be really interesting and useful to you! People who have started the construction of any structure must have an idea of what is needed for what, what parts the structure consists of, what materials they will need and how much this or that material costs. Before starting construction, you need to develop a plan for the structure and indicate all the parameters. Let's consider one of the important details of the structure and this will be the hipped roof and its rafter system.
Hip roof design
There are several types of roofs, the most aesthetically pleasing and durable is the hipped roof.
Such a roof will withstand strong winds, snowfalls and heavy downpours. A hip roof may not be complex in design and has some elements.
A hipped roof differs from a gable roof in appearance and design. The design of the hipped roof is somewhat more complicated, but for small buildings you can build it yourself.
Standard roof has trapezoidal slopes and triangular slopes.
Semi hip- two trapezoidal slopes, two cut hip ones. This design makes it possible to equip an attic with large windows in the attic.
It differs from a hip roof.
A complex hipped roof has windows and valleys.
The construction of this roof can only be done by professionals, or take a project with calculations of materials.
The hip roof includes the same parts as, but due to some complexity of the design, additional frame parts are required for its construction.
Details of the hipped roof:
- this is a beam placed on the upper part of the main walls;
Lezhny– these are support beams that are located inside and laid on load-bearing walls;
– these are diagonal, slanting or side bars;
Springs and racks- these are supports that support the truss structure;
Purlin or ridge beam- this is a horizontal support for the rafters located on top of the roof;
Crossbars and puffs– these are horizontal parts that connect the side rafters;
Narozhniki– parts that are placed on diagonal rafters;
Wind beams and struts– these are spacers that increase the strength of the roof;
fillies- these are the boards that form the desired roof overhang.
The design of the roof determines what parts can be used during construction, for example, cornices over windows or a porch, sheathing.
Before starting construction, it is necessary to calculate the amount of raw materials, also determine what size and shape the roof will be, then make a drawing.
Construction technology.
To distribute the load of the rafter system and external factors, a mauerlat and planks are laid on the main walls.
For them, timber with a cross section of 100×150 mm or 150×120 mm is used, in some cases reinforced concrete beams are laid.
Installation of rafter group and sheathing
On a regular hip roof, the side rafters are installed in the same way as those on a gable roof.
A board with a width identical to the width of the rafter board (150 mm) is applied to the ridge beam in the place where the outer post is located and a template is made from it.
The distance between the rafters should be from 0.5 to 1.5 m.
Diagonal rafters are made from two connected boards, so they carry an increased load. The preparation for diagonal rafters is carried out using the above method.
The cuts on the boards for diagonal rafters must be made at an angle of 45 degrees to the plane of the board, since from below they rest on the corner of the mauerlat, and from above on the rack. Narodniks fill the spans between the diagonal rafters on the hip slopes.
Making the sheathing
The roof is no less important element of the house than the foundation and walls. Its design sets the mood for the entire architectural ensemble, making the building neat and attractive. The hipped roof has gained wide popularity not only because of its high reliability and external attractiveness, but also due to the opportunity to equip additional structures - attic and dormer windows, bay windows, etc. Despite the fact that the installation of such a roof is a little more expensive and more complex than a gable structure , it is still easy to build it with your own hands.
Advantages of hip roofs over gable structures
One of the main tasks that appears even at the stage of designing your own home is choosing the type of roof. The presence of many options among gable and hipped structures requires an answer to the question of which roof to give preference to. And although the aesthetics of the structure plays an important role, the criteria of reliability and practicality still come to the fore.
A gable roof is a classic structure that is formed by two opposite slopes and a pair of vertical end parts called gables. The spacious under-roof space allows you to equip an attic, living space or use the attic for domestic purposes.
The classic gable roof is easily recognized by a pair of rectangular slopes that adjoin each other along the central axis of the building, and two triangular gables at its ends
Structures of this type, due to their simplicity and practicality, remained the most popular in individual construction for a long time. At the same time, the dependence of the roof geometry on the size of the building, as well as the complication and rise in cost of the structure when arranging the attic, forced the search for other, more practical and functional options. And they were found in the form of a variety of hipped roofs, which are based on a pair of triangular and two trapezoidal slopes. The latter are often called hips, and the roof itself is called a hip roof. When erecting a structure of this type, there is no need for gables and it becomes possible to make the building more modern and original.
The slopes of the simplest hip roof define surfaces in the form of two trapezoids and a pair of triangles
There are several advantages of hip roofs over traditional gable structures:
- the possibility of installing attic windows directly on the slopes;
- increased strength, reliability and stability of the rafter system;
- increased resistance to weather factors;
- the possibility of increasing the area of the attic by simply reducing the width of the base of the hip;
- more uniform distribution of roof weight;
- improved temperature conditions when arranging the attic space.
Don’t be fooled by the many advantages of a more stylish hipped roof - it also has disadvantages. These include a more complex design, a slight reduction in the size of the attic space and wasteful use of roofing material. As for expenses, the budget required for the construction of one and the other roof differs slightly.
The hipped roof is not a know-how in architecture - its design has been known since ancient times
Classification of hip roofs
Differences in the shape of buildings, as well as the requirements for functionality and practicality of the traditional hip roof, have led to many variations. If we do not consider the most exotic of them, then we can distinguish several main types of hipped roofs.
- Traditional hip roof, the side slopes of which reach the eaves level. To construct its main surfaces, straight rafters are used, and the ribs of the hips form beams extending from the ends of the ridge. The elaborate design and distribution of the weight of the roof over a larger area allows not only to position the overhangs on the same line, but also to increase their reach. Thanks to this, the façade of the building is reliably protected from rain even in strong gusts of wind.
Glazing elements are often built into the slopes of a classic hip roof.
- A hip roof can be installed on a house that has a square shape in plan. A feature of this design is the slopes of the same configuration. Their ribs converge at one point, and their hips have the shape of isosceles triangles.
Hip roofs are widely used in modern individual construction
- Half-hip roofs got their name because of the shortened hips. Unlike traditional roofing, their length is reduced by 1.5–3 times compared to the size of the main slopes.
The side slopes of half-hip roofs have a shortened length, so they do not reach the eaves line
- The Danish half-hip roof has a small gable under the ridge and a short hip on the eaves side. This design allows you to install ventilation and lighting elements directly into the vertical end of the roof, thereby eliminating the need to install skylights.
The Danish project is good because it allows you to easily equip attic spaces
- A half-hip Dutch roof has a vertical gable that divides the hip into two short slopes. Although the “Dutch” rafter system has increased complexity, it allows you to make the attic space more spacious and practical. In addition, this design is excellent for installing vertical glazing in the attic.
A roof built according to a Dutch design is still rare in our area.
- A sloping hip roof has several slopes of different sizes on one slope. Thanks to their different slopes, it is possible to increase the volume of the under-roof space. Although a broken structure cannot be called simple, houses with such a roof are very common. The reason for its popularity is the opportunity to arrange additional living rooms on the upper tier. For this reason, a roof with broken slopes is often called an attic roof.
The sloping roof makes the architecture of the building somewhat heavier, but it makes it possible to arrange several living spaces in the attic space
There are also more complex structures from many hips, as well as those in which a hipped roof is combined with other types of roofing systems. The design and installation of such a roof requires many years of experience and knowledge, so it is better to entrust the construction of a sophisticated roof to specialists.
Design of hip roofs
When developing a hip roof, all types of loads that will affect it are taken into account. To do this, you must first resolve several important issues:
- purpose of the attic space;
- roofing material;
- degree of atmospheric influence in the construction region.
Based on these factors, the degree of slope of the slopes and the roof area are determined, the loads are calculated and a decision is made on the design and parameters of the rafter system.
Geometric parameters of slopes
The angle of inclination of the slopes depends on the snow and wind load, therefore it varies within a very wide range - from 5 to 60 degrees. In areas with rainy weather and high snow cover, roofs with a slope of 45 to 60 degrees are erected. If the region is characterized by strong winds and minimal precipitation, then the slope can be reduced to the very minimum.
When determining the angular parameters of the roof, it is necessary to take into account what material it will be covered with:
- slate sheets, ondulin, roofing metal and rolled materials are laid on slopes with a slope of 14 to 60 degrees;
- the tiles are mounted on a surface with a degree of slope from 30 to 60 degrees;
- Roll coating is used on sloping slopes - from 5 to 18 degrees.
Having decided on the angle of the roof, it is not at all difficult to calculate at what height the ridge will be. To do this, use simple trigonometric formulas for a right triangle.
Roof area
Even the most complex hip roof consists of individual slopes that follow the contours of the simplest geometric shapes, so most often for calculations it is enough to know the linear dimensions of the base and the angles of inclination of the hips.
To determine the square footage of the roof, it is necessary to add up the areas of the slopes of which it consists
The total roof area is calculated by summing the square footage of the individual hips. Slopes of complex configuration are divided into several simple surfaces, after which separate calculations are carried out for each of them.
The principles for calculating the geometric parameters of hip roofs are based on calculations for simple surfaces
Load calculation
Loads acting on a hipped roof are divided into two types:
- permanent,
- periodic.
The first includes the weight of roofing materials, rafters, sheathing and other frame parts. The second is the forces exerted by precipitation and wind force. In addition, when calculating, one should take into account the payload in the form of various engineering systems and communications attached to the elements of the rafter system.
Based on SNiP, when designing a roof it is necessary to assume a snow load of 180 kg/sq.m. m. If there is a danger of snow accumulation on the roof, this parameter increases to 400–450 kg/sq. m. If the roof has a slope angle of more than 60 degrees, then the snow load can be ignored - precipitation does not linger on surfaces with such steep slopes.
The force of wind loads is much less - up to 35 kg/sq. m. If the roof slope is from 5 to 30 degrees, then the effect of the wind can be neglected.
The above parameters of atmospheric influences are average values accepted for the middle zone. When performing calculations, correction factors should be used depending on the region of construction.
Calculation of the rafter system
When calculating the rafter system, the pitch of the rafters and the maximum load they can carry are determined. Based on these data, a decision is made to install braces, which help redistribute the load, and tie-downs, which protect the frame from loosening.
The main load of the hip roof falls on the diagonal rafters
The presence of hips on hipped roofs, in addition to the usual rafters, requires the installation of diagonal rafters (in other words, slanted ones) - those that are attached to the ridge and directed to the corners of the building. Their length is greater than the transverse node elements of the roof. In addition, shortened elements - sprigs - are attached to the diagonal ribs. Compared to conventional rafters, slanted legs experience a load increased by 1.5–2 times, so their cross-section is doubled, and to ensure multi-span they are supported by one or two racks.
Often, hip roofs have a complicated rafter system, which, in contrast to a simple hipped structure, places additional load where vertical supports are installed. This feature must be taken into account when calculating the strength of a wooden roof frame.
The distance for laying the rafters is called the pitch and is determined based on the length of the rafter leg and the cross-section of the lumber used. It is most convenient to determine this parameter using special tables, one of which is given below.
Table: dependence of the cross-section and pitch of rafters on their length
Manual calculations are quite labor-intensive. To reduce design time, you can use one of the online calculators to determine the parameters of hip roofs. With its help, you can determine not only geometric parameters, but also a lot of other equally important factors:
- amount of moisture and heat insulation, taking into account overlaps;
- amount of roofing material, including waste generated during cutting;
- the volume of lumber required for arranging the rafter system;
- length of overhangs, etc.
Video: using a construction calculator to calculate a roof
What materials will be needed to assemble the rafter system?
For the construction of a hip roof, timber and boards made of larch, pine and other coniferous wood are best suited. When choosing material for construction, it is necessary to carefully reject defective boards. Fungal damage, knots and cracks reduce the strength of the boards and affect the durability of the roof. When the wood moisture content is more than 22%, the lumber is stacked in the open air and dried. It should be understood that under-dried boards can warp, and this, in turn, will lead to a violation of the geometry of the roof with possible damage to the finishing coating.
To assemble a wooden frame, a rectangular beam with a cross-section from 80x80 mm to 150x150 mm is used - the exact parameters are determined by calculation or using the table above. As an alternative, you can use a board with a section of 50x100 mm or 50x200 mm. If there is a need to strengthen the rafter leg, then paired boards are used.
For reliable fastening, as well as increasing the rigidity of the wooden frame, steel brackets and other metal elements are used. Often, steel supports, rather than wooden ones, are installed under particularly loaded ridge girders. Combined frames have increased strength and reliability.
Features of the rafter system
In order to correctly design and install a hip roof, it is necessary to understand in detail its design, as well as the design features of the most common types of hip roofs.
The structure of the rafter system in detail
The frame of a hip roof consists of most of the same parts as a gable roof, but a more complex rafter system requires the installation of additional elements. Upon closer examination, the following components can be found:
All these elements can be found in any type of hip roof. The only exception is the hip roof, which does not have side rafters or ridge beams.
In wooden and frame houses, the rafter system is installed without a Mauerlat. In the first case, its functions are taken over by the outer crowns, and in the second - by the upper trim.
Types of rafter systems for hip roofs
Since the basis of the hip roof rafter system is made up of slanted rafters, when installing the roof frame, you must adhere to the following rules:
- In structures where the slanted legs experience increased load, timber of double thickness is used for their manufacture.
- The splicing of individual parts of diagonal rafters is carried out in places with maximum load (most often in their upper part) and strengthened with the help of struts and vertical posts installed at an angle of 90° to the rafter legs.
- When making slanted rafters, allowance should be made for local trimming, so the estimated length of the beam is increased by 5–10%.
- Critical connection points of slanted rafter legs must be reinforced with metal fasteners - staples, twists or perforated construction strips.
When choosing a rafter system, it is necessary to take into account the size of the building and the presence of internal supports or permanent walls. Based on specific conditions, a scheme with hanging or layered rafters is chosen.
Hanging rafter system
A hanging rafter roof structure has no centerline supports, so the bulk of the weight falls on the outer perimeter walls. This feature manifests itself in the redistribution of internal forces - the rafter system is subjected to compressive and bending loads. As for the walls, significant pushing forces are transmitted to them. To eliminate this factor, each pair of rafters is connected to each other by so-called ties - jumpers made of wooden beams or rolled metal.
The tie can be located either at the base of the rafter legs or above. In the first case, the lintel will also act as a transverse beam, which is a good option when constructing an attic roof. If the tightening is installed in the area of the midline or above, then it will only serve as a securing link. It should be noted that the cost of the rafter system depends on such a seemingly insignificant moment as the installation height of the tie rods. The higher the transverse jumpers are located, the larger the cross-section of all components of the wooden frame should be.
Hip roofs with layered and hanging rafters have differences between the supporting elements of the structure
Construction with layered rafters
A hip roof with layered rafters is suitable only for those houses whose interior space is divided into two equal parts by a main wall or support pillars installed to support the ceiling. In this case, the lower edge of the rafter legs rests on the mauerlat, and the middle part rests on the load-bearing partition. The presence of additional support points allows you to relieve the elements of the rafter system by removing alternating horizontal forces from them, as well as from the walls of the building. Like roof beams, rafters begin to work only in bending. A frame with layered rafters becomes more rigid and durable compared to a structure that uses unsupported rafters. And this despite the fact that in the first case you can use timber of a smaller cross-section. And this helps reduce the weight of the wooden structure and reduces the cost of purchasing lumber.
Installation of a hip roof
The assembly of the rafter system must be carried out in a strictly defined order. This is necessary in order to correctly install and secure all structural elements of the roof.
- To redistribute the load exerted on the walls by the roofing structure, wind and precipitation, a Mauerlat is laid on the external walls. In individual construction, timber with a cross-section of at least 100x150 mm is used for these purposes. Anchor pins are used to secure the longitudinal beams of the structure. They must be laid in the upper rows of the masonry at the stage of wall construction. Waterproofing of the Mauerlat is carried out using two layers of roofing material, which is laid on top of the load-bearing walls.
The Mauerlat is attached to the load-bearing wall using bolts or anchors
- If it is necessary to install vertical supports, beds are laid on the load-bearing walls. Wooden pads are used to horizontally level the elements of the rafter system. In the future, this will greatly simplify the installation of racks and purlins. If capital partitions are not provided for in the building plan, then vertical supports are mounted on floor beams. To do this, they are strengthened by joining two 50x200 mm boards or using one 100x200 mm beam.
Support of vertical posts on beams is allowed only if the structure rests on a permanent pier
- Set up support posts. To level them, use a plumb line or laser level, after which temporary supports are installed. Metal angles and plates are used to attach the vertical support to the beam or horizontal beam.
- Purlins are laid on top of the racks. A traditional hip roof requires the installation of one purlin, which, in fact, forms the ridge. Tent structures require the installation of four purlins. As with the installation of racks, fastening is carried out using metal corners and self-tapping screws.
The ridge purlin can be attached either directly to the rafter leg or using wooden plates
- Preparing the rafters. The side rafters of simple hipped roofs are mounted in exactly the same way as the rafters on a gable roof. First you need to make a template. To do this, from the side of the outer support, apply a board of the same width as the rafters to the ridge. Its thickness should not exceed 25 mm - the template should be light. On this board, mark the notch necessary for reliable support and precise fit of the rafter leg to the ridge beam, as well as a cutout corresponding to the junction with the Mauerlat. The marked areas are cut out and then used for quick preparation of the rafter legs.
Making a template can reduce the time it takes to prepare rafters for installation
- By applying the manufactured sample to the purlin, it is necessary to check whether precise adjustment of the rafters is necessary. If there are gaps, cuts in the rafters are made taking into account the amendments. After all the supporting legs are ready, they are set in increments of 50–150 cm and attached to the Mauerlat and the ridge. For installation, staples are best suited, but strong metal corners can also be used.
- As already mentioned, diagonal rafters are made from spliced boards or timber of increased cross-section. To install them, you will also need a template, which is prepared in full accordance with the method described above. Since the slanted rafters are adjacent to the corner of the mauerlat on one side, and rest on the racks on the other, the cut is made at an angle of 45° to the plane.
The layout of rafters and soffits on a hip roof is carried out according to a template
- In the gaps between the sloped rafters, sprigs are attached. Their step corresponds to the distance between the rafters, and the diagonal legs and the mauerlat act as support points. The load experienced by the rafters cannot be compared with the weight that falls on the rafters, so the former can be constructed from boards 30–50 mm thick. To speed up installation, you will need a template with notches on the side of the diagonal rafters and the mauerlat, but the cutouts on half of the frames must be made in a mirror image.
The use of metal fasteners makes the rafter system more rigid and stable
- If there is a need, fillies are attached to the rafters and frames. The ends of the rafter elements are cut along the cord.
Attaching the rafters to the Mauerlat can be done in several ways
- Strengthen the slopes and side rafters. In the first case, vertical trusses are used, and in the second, struts installed at an angle of 45° are used. They are supported on beds or beams.
- After the rafter system is assembled, a roofing pie is installed on top of it.
The rafter system is prepared for installation of roofing materials
Lathing and insulation
Before proceeding with the installation of the sheathing, a vapor barrier and, if necessary, rolled thermal insulation are laid on top of the rafters. The top layer of insulation is covered with a waterproofing film, which is mounted with an overlap of 10–20 mm wide and secured to the beam with a construction stapler. After this, counter battens are nailed to the rafters. If the roofing pie is installed without insulation, then a vapor barrier is not required - a layer of moisture-resistant material will be sufficient. Of course, additional slats will not be needed in this case, since the boards supporting the roof will be attached directly to the frames and rafter legs.
Depending on the type of roofing material, one of two types of sheathing is used on hip roofs:
- continuous;
- sparse.
The first is most often equipped for a soft roof and only in some cases - for arranging an attic space. This type of lathing is made from boards with a width of 100 to 200 mm and a thickness of at least 20–25 mm. Installation is carried out without gaps. In addition, the use of plywood sheets and OSB boards is allowed. Their advantage is an extremely flat surface, which allows you to lay roofing material with minimal time and effort.
Under the soft roof, a continuous sheathing of OSB, plywood or boards packed without a gap is installed
For sparse sheathing, the same boards are used as in the first case, but they are mounted with a gap. Since this type of base is used for laying slate, corrugated sheets, metal tiles and roofing iron, the distance between individual boards must take into account the characteristics of the roofing material.
The sheathing is fastened with nails, the length of which is equal to triple the thickness of the boards. If self-tapping screws are used for fixation, then you can use a shorter threaded fastener with a length corresponding to double the thickness of the lumber.
To fasten slate, ondulin and other sheet materials, use sparse lathing
The wooden base of the roofing pie is mounted from the bottom up, with the first board of each slope aligned parallel to the mauerlat. First, the sheathing is stuffed on the hips, after which the protruding edges are cut off with a hacksaw flush with the diagonal ribs. Next, they begin to fasten the lumber on the main slopes, releasing the edges of the boards beyond the sloped rafters. After this, the ends of the boards are sawed down similarly to the first case.
Video: building a hip roof with your own hands
Typical hip roof design
When building a simple hip roof, you can use a standard project developed by specialists. Project documentation includes:
- technological map;
- roof plan;
- rafter system diagrams;
- drawings of sections and corner connections;
- statement and specification with a complete list of materials used.
As a sample, below is documentation for a typical hip roof design for a house with an area of 155 square meters. m.
Gallery: drawings and diagrams of a hipped roof
The drawing indicates the exact dimensions of all roof elements. Triangles lie at the base of the rafter truss. Rafters of trapezoidal slopes rest on the long load-bearing walls of the building. Tie-rods are installed at the base of the rafters and act as floor beams. When creating a project, it is necessary to take into account the length of the rafters, their pitch, the recommended cross-section of the beam or board. rafter fastenings use wooden and metal products. Fastenings allow you to transfer the load from one element of the system to another
Despite the apparent complexity of a hipped roof, building it with your own hands is not much more difficult than a gable structure. It is only important to carefully understand the purpose of the individual elements and the principles of constructing the rafter system. Otherwise, the reliability and durability of the roof will still depend on adherence to technology and careful installation. As for the additional difficulties and costs, they will be repaid with complete satisfaction from the work, which will make the building brighter and more attractive.
The labor intensity of the work when building a hipped roof is not much higher than a regular gable roof, but this does not mean that a hipped roof can be built with your own hands as simply as a regular one, with two symmetrical slopes. The main difficulty is that a hip roof requires very precise engineering calculations and knowledge of technology, especially if you do not have good practice in building this kind of roof.
Why is a house with a hipped roof better than a gable roof?
Why is an ordinary gable roof installed mainly on simple outbuildings, and why a hip roof is chosen for residential premises:
- The appearance of the hipped roof option looks much nicer and more elegant than the double structure;
- Even a simple hipped roof can withstand the elements much better due to smoother contours and aerodynamics. Even in the strongest winds, the rafters of the frame remain almost equally loaded, due to the correct balancing of the diagonal rafters;
- Two additional slopes shed water better, dry under the influence of the wind and thereby protect the roof of the house from flowing, as happens with straight gables. Thus, significantly higher thermal insulation and frost resistance are achieved for a hipped roof.
Important! The four-slope roof design, unlike the “kopeck piece”, has a high degree of adaptation.
For climates with high rainfall, the Danish version with steep main slopes and two hips is perfect; for the steppe zone with strong winds, a low tent frame with large overhangs and an average angle of inclination.
It will be most convenient to use a hipped roof in houses where the attic space is not allocated as a residential area, but is used for economic purposes. Due to the appearance of two additional slopes, the space and usable area of the attic is reduced by approximately 25%. But if desired and the size of the attic space is sufficient, you can equip a small room instead of an attic, even with windows and a balcony, as in the photo.
But in this case, instead of a simple system of vertical posts on which the ridge girder rests, additional horizontal beams - crossbars - will need to be installed in the structure of the hipped roof, which will play the role of a ceiling for the attic space.
How to make a hip roof
First of all, it’s worth understanding how a 4-slope roof differs in detail from the double-slope version.
The main difference between a 4-slope rafter system and a double symmetrical roof
The differences in design will be most obvious in the diagram with a simple rectangular version of the hipped roof shown in the photo:
Important! Most elements of additional slopes require very careful adjustment, so often diagonal rafters and frames are assembled with a preliminary “grab” using self-tapping screws, and only after final adjustment they are replaced with a bolted connection or knocked down with nails.
Do-it-yourself hipped roof, sequence of work
The most difficult part in building a rafter system for a hipped roof is the stage of hanging the diagonal rafters. Firstly, the angle of inclination of the diagonal rafters and the pressure with which they rest on the ridge girder must be equal to the parameters of the pair of rafters on the other side. The areas of the slopes and the angles of inclination in a hipped roof must be absolutely equal.
Secondly, an imaginary line drawn between the joining points or vertices of the triangles formed by the diagonal rafters on both sides must run exactly along the axis of the ridge beam, both horizontally and vertically. The main difficulty in assembling a hipped roof is to correctly align and adjust the position of the diagonal rafters.
At the preparation stage for assembling a hipped roof, a board or mauerlat beam is laid, and it is important to carefully level the plane of the board horizontally. Preliminary markings of places for installation of side rafters, truss supports and tightening are applied to the Mauerlat. Installation of a hipped roof is greatly simplified if a reinforced concrete slab is used as the ceiling.
After laying out and fastening the tightening, the ridge frame or “bench” is assembled. Essentially, this is a ridge beam installed on vertical posts. Longitudinal and transverse struts are sewn to the posts, ensuring the stability of the frame until the hip rafters are assembled.
Before laying out the diagonal rafters, the ridge frame must be supported with a pair of temporary beams, which are attached to the mauerlat and to the outer post of the “bench”. This will prevent the ridge frame from tipping over under the pressure of the diagonal rafters on the other side.
Next comes the most difficult part. First, the actual length of each of the sloped beams is determined; for this, a nail is hammered into the fulcrum at the end of the ridge beam and the length from the nail to the fulcrum on the mauerlat is measured with a cord. Before installing the diagonals, each of the slanted rafters is measured and cut according to its cord length.
Having installed the bevel elements on the Mauerlat, determine the line of contact and the cut of the contact surface. Having trimmed the support plane of the slope beams, they are laid on the end of the ridge girder.
The lower ends of the diagonal beams are installed in the corner joint of the mauerlat beam with an undercut of the supporting surface of the beam according to the diagram shown. Sometimes the shape of the cut is made according to a template, but it is safer to mark the cut line manually.
Ideally, an imaginary vertical plane drawn through any sloping rafter should be parallel to the plane of the sloping beam located on the opposite side of the hipped roof.
If everything is done correctly, the two diagonal rafters of the hipped roof will be exactly along the axis of the ridge beam. To avoid deflection, long enough braces need to be installed with struts and truss supports with the installation of temporary fasteners made of self-tapping screws. Similarly, install the rafters from the opposite slope and align the elements with maximum accuracy. To increase the rigidity of the hip slopes, several flanges are cut out and installed at the edges of the diagonal beams.
Then they move on to laying ordinary rafter beams. Fastening to the Mauerlat is carried out using a standard bolt-nut connection or using steel angles. In the upper part, the rafter board is usually sawed down according to a template and laid on the ridge beam.
Usually, after hanging the rows on the ridge girder and the mauerlat, additional crossbars are installed in the upper part, which reduce the bursting effect of the frame of the hipped roof. After installing all the rafter beams and aligning the main strength elements of the hipped frame, they proceed to the permanent fastening of all rafters on the mauerlat and ridge girder.
At the next stage, struts are installed and fastened under the ordinary rafters, and the triangular slopes are “filled” with external beams. Each of the splices is cut to its own length according to the diagram below and installed in a checkerboard pattern; this avoids weakening of the beam due to the coincidence of the cuts on opposite sides.
All elements are secured with nails, self-tapping screws and bolted connections with overhead steel plates and angles.
Final operations
After assembling the main frame of the hipped roof, fillets are stuffed onto the ends of the rafters - short boards that form a row of roof overhangs along the wall. The cut line is measured along the ends of the fillies, trimmed so that the ends are in the same plane, and the cornice board is sewn on. The lower part of the fillies is lined with clapboard or regular board.
After treating the wood of the beams with an antiseptic composition, they proceed to stuffing the sheathing boards. The thickness of the boards, the amount of material and the nailing points are chosen based on what kind of roofing they plan to lay on a given hipped roof.
Conclusion
The hipped roof is deservedly considered one of the most convenient and practical roof structures. If you are planning to build a hipped version with your own hands, in addition to correctly calculating the structure, you will need experience in leveling and adjusting the position of each of the beams. Therefore, it would be right to get the necessary experience and skill in working with hipped roofs from more experienced craftsmen.
Many people like houses with hipped roofs. Even though they require the most materials, and therefore the most money, they are popular. Firstly, because they give even a simple “box” a more interesting look. Secondly, because they are durable and reliable. And even though the rafter system of a hipped roof is one of the most complex, it can be developed and made with your own hands.
Types of hipped roofs
Hip roofs are the most expensive and difficult to construct. But despite this, they were and remain popular. And all because they look more attractive than all other types of roofing, have high mechanical strength, and resist wind and snow loads well. A house with a hipped roof or even a gazebo looks “more solid” than any other.
Even a simple “box” under a 4-pitch roof looks impressive
There are two main types of 4-pitch roofs: hip and hip. The hip roof is suitable for square buildings, the hip one - for rectangular ones. In a hip roof, all four slopes look like triangles and they all converge at one point - in the center of the square.
General structure of a hip roof
The classic hip roof has two slopes in the form of trapezoids that converge at the ridge. These slopes are located along the long side of the rectangle. The other two slopes are triangles that are adjacent to the extreme points of the ridge beam.
Hip roof construction in general terms
Despite the fact that there are four slopes in any case, the design and calculation of these roofs are different. The assembly order is also different.
Half-hip
Hip roofing is much more common - after all, there are much more rectangular buildings than square ones. There are several more varieties of it. For example, half-hip ones - Danish and Dutch.
Half-hip roofs - Danish and Dutch
They are good because they make it possible to install full-fledged windows in the vertical part of the side slopes. This allows you to use the under-roof space as a living space. Of course, compared to a full second floor, there is less living space, but construction costs are also not so high.
Slope angle and roof height
The angle of inclination of a hipped roof is determined based on snow and wind loads in your region. The higher the snow load, the higher the ridge must be raised so that the slope is steeper and the snow does not linger in large volumes. In strong winds, on the contrary, the ridge is lowered lower to reduce the area of the slopes and, consequently, the wind load.
Even when choosing the angle of inclination of the roof slopes, they are guided by aesthetic and practical considerations. With aesthetics, everything is more or less clear - the building should look proportional. And it looks better with fairly high roofs - 0.5-0.8 of the height of the first (or only) floor.
One of the options for the rafter system for a half-hip roof
Practical considerations come in two directions. First, if the under-roof space is planned to be used as a living space, pay attention to the area that will be comfortable for use. It is more or less comfortable to be in a room with a ceiling height of 1.9 m. And even then, this is for people of average height. If your height is higher than 175 cm, you will have to raise the bar.
On the other hand, the greater the height of the roof, the more materials will be required for its manufacture. And this is the second practical aspect that needs to be taken into account.
There is one more point that should be taken into account: roofing materials have a minimum and maximum slope angle with which this coating can “work”. If you have certain preferences for the type of roofing material, take this factor into account. This determines the height to which the rafter system of a hipped roof should be raised (relative to the walls).
Hip type hip roof rafter system
If a hip roof is made, it is most often a hip roof. Let's talk about it first. The central part of the rafter system repeats the gable roof system one to one. The system can also be with layered or hanging rafters. Hanging rafters are installed “in place” - on the roof; two people are enough for such work. Layered roof trusses, in the form of triangles, can be assembled on the ground, and then, ready, lifted and installed. In this case, there is less work at height, but to lift and install ready-made trusses, you need either equipment (a crane) or a team of four or more people.
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Hip roof rafter system with layered rafters
The main differences between the rafter system of a hip roof are in those places where the rafters are shortened (rafter half-legs) and a hip is formed - triangular slopes. Here diagonal rafters are installed, which are also called rafters. They rest on the outer or inner corners of the building and are longer than ordinary rafter legs. Particular attention should be paid to diagonal rafters, since they carry one and a half loads (when compared with neighboring rafters). Therefore, the corner rafter legs are made reinforced - they are assembled from two boards, joining them in width using nails. Also, to support the diagonal rafter legs, additional racks and slopes are installed, which are called a truss block.
Rafter system of a hipped roof: installation of a hip roof
Another rafter system for a hip-type hipped roof is distinguished by the fact that the Mauerlat is laid around the perimeter of the building, and not just along the long sides of the box. This is understandable - the rafters are located along the perimeter, and not just on two sides, as in a gable roof.
Mauerlat- element of the roofing system of a building. It is a beam or log laid on top along the perimeter of the outer wall. Serves as the extreme lower support for the rafters.
Diagonal rafters
As already mentioned, slanted (corner) rafters carry an increased load: from the shortened rafters of the side slopes and from the hips. In addition, the length of the diagonal rafters of a hip roof usually exceeds the standard length of lumber - it is more than 6 meters, so they are made spliced and doubled (paired). This solves two problems at once: we obtain a beam of the required length and increase its load-bearing capacity. Two paired boards can withstand greater loads than a solid beam of the same section. And one more point: spliced beams for slanted rafters are made of the same material as ordinary rafter legs. It's cheaper, and you don't need to look for special material.
How to pair rafters from boards
If spliced beams are used, diagonal rafters are usually secured by installing struts and/or trusses (racks).
- If the length of the beam is up to 7.5 m, one strut is sufficient, which rests on the upper part of the beam.
- For lengths from 7.5 m to 9 m, an additional stand or truss is installed. These supports are placed at the bottom, 1/4 of the length of the rafters.
- When the length of the inclined rafter is more than 9 meters, a third, intermediate support is needed - a stand that supports the middle of the purlin.
Sprengel- a special system that consists of a beam resting on two adjacent external walls. A stand rests on this beam, supported on both sides by slopes (the slopes are installed if necessary).
Truss beams support diagonal rafters
A truss truss is usually not considered, but is made from the same materials as the truss system. For the beam itself 150*100 mm, for the racks - 100*100 mm, for the slopes - 50*100 mm. This can be a beam of a suitable cross-section or spliced beams.
Supporting the rafter leg
The upper end of the diagonal rafter legs rests on the ridge beam. The exact execution of this assembly depends on the type of system and the number of runs.
If there is only one purlin, the consoles are made 10-15 cm longer than the rafter frame. If such an outlet is too large, it is then trimmed. But it’s not worth making it shorter - growing it is much more difficult and expensive. The slanted diagonal legs will rest at this point.
Support unit for diagonal rafter legs with one ridge purlin
The rafters are cut at the desired angle and joined on the console. Fastened with nails. The connection can be strengthened using metal overlay plates.
If there are two ridge spans (done if an attic-type living space is planned), the connection method depends on the material from which the rafters are made:
- If spliced boards are used, a truss is required, which rests on the outriggers of the ridge girders. Diagonal rafters are trimmed and supported on a truss post.
- If timber is used, a crimp is installed at the point of support - a piece of board at least 50 mm thick. The board is attached with nails to two purlins, and to this board there are already rafter legs that will form a hip.
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If there are two ridge beams
The lower part of the slanted rafter legs is trimmed horizontally and attached to the mauerlat or trim board. For greater reliability of the unit, you can install an additional oblique beam and fix the corner beam to it (in the figure below).
Attaching the sloped rafter to the mauerlat
Fastening - with nails on both sides; if necessary, it can be additionally secured with wire twists or clamps.
How to attach sprigs and half-legs
Shortened rafters of the side slopes (also called half-legs) are attached to the installed diagonal rafter legs on one side, and on the other side - rafters that form a hip. They must be placed in such a way that the joints do not coincide. Sometimes for this you have to change the distance between the external rafters (preferably in the direction of decreasing the pitch).
Typically, shortened rafters are trimmed and secured with 2-3 nails on both sides. This type of fastening is sufficient in most cases. But, if you want to do it “correctly”, under each rafter you need to make a “notch” - a notch no more than half the thickness of the beam. The rafters are trimmed, installed in the desired position, and the desired contour is drawn on the beam (an uneven trapezoid is obtained due to different connection angles). A recess is cut out along the resulting contour, into which the half-leg is inserted, after which it is secured with nails on both sides. This is a complex knot, and it takes a long time to do. But the load-bearing capacity of such a connection is much higher. There is another option, which is much simpler in execution, but differs little in reliability.
Mounting methods
The optimal way to attach the splints and half-legs to the mowing beam is to fasten them on nails with the additional installation of cranial bars (see figure above). For this, a beam with a cross section of 50*50 mm is used, which is nailed along the lower edge of the beam between the fixed rafters. In this version, the beam becomes an I-beam, which greatly increases its elasticity and increases its load-bearing capacity.
How to fasten the lower ends of the rafters
The method of fastening the lower ends of the rafters depends on what type of rafter system of the hipped roof is chosen - with hanging or layered rafters, and what kind of scheme is used. A system with sliding rafters (usually used for buildings for which thrust loads are contraindicated - wooden, frame, lightweight concrete) is implemented using special metal fasteners. They consist of two parts. One is installed on the embedded board, the second - on the rafters. They are connected to each other movably - using a long slot or plate.
Sliding mount for rafters
With this device, when the load changes, the roof “plays back” - the rafters move relative to the walls. There are no thrust loads; the entire mass of the roof and precipitation is transferred vertically downwards to the walls. This fastening allows you to compensate for uneven loads that arise with a complex roof structure (with junctions in the form of the letter G or T).
Rigid fastening can be done in different ways - with a cutout for the Mauerlat/tying board or with a hemmed support bar. Fastening is usually done with nails; it can be reinforced with metal plates and corners.
Several options for attaching rafters to the Mauerlat
The connection with the cutout is made if the roof has a hipped roof with an outlet - overhangs. Usually the overhangs are quite large and, in order not to buy long beams, they are extended by adding boards that are nailed right through to the bottom of the beams. This allows you to make the overhangs as long as you want without overspending on materials.
Danish half hip roof
The rafter system of a Danish-type hipped roof differs from the classic hip roof. The difference is in the design of the hip - here, at some distance from the ridge, a support board with a thickness of at least 5 cm is packed. Diagonal double rafters are attached to this board. How low to lower the support board is your choice. But the lower the board is lowered, the smaller the angle this slope will have, and the worse the precipitation will be. If the half-hip area is large, you will have to calculate the load and select the thickness of the rafters.
