Knots of wooden roofs of residential rural buildings. How are the fastening points for the roof truss system created? Rafter truss designed for soft roofing

At the heart of every roof is a large number of beams, rafters, posts and purlins, which are collectively called the rafter system. Over the centuries-old history, many types and methods of its organization have accumulated, and each has its own characteristics in the construction of nodes and cuts. Read more about what a rafter system can be gable roof and how the rafters and other elements of the system should be attached, let’s talk in more detail.

Design of a gable roof truss system

In cross-section, a gable roof is a triangle. It consists of two rectangular inclined planes. These two planes are connected at the highest point into a single system by a ridge beam (purlin).

Now about the components of the system and their purpose:

• Mauerlat is a beam that connects the roof and walls of a building, serves as a support for rafter legs and other elements of the system.
• Rafter legs - they form the inclined planes of the roof and provide support for the sheathing under the roofing material.
• Ridge purlin (bead or ridge) - combines two roof planes.
• A tie is a transverse part that connects opposite rafter legs. Serves to increase structural rigidity and compensate for thrust loads.
• Lezhny - bars located along the mauerlat. Redistribute the load from the roof.
• Side purlins - support the rafter legs.
• Racks - transfer the load from the purlins to the beams.

There may still be fillies in the system. These are boards that extend the rafter legs to form an overhang. The fact is that to protect the walls and foundation of the house from precipitation, it is desirable that the roof ends as far from the walls as possible. To do this, you can take long rafter legs. But the standard length of lumber of 6 meters is often not enough for this. Ordering non-standard is very expensive. Therefore, the rafters are simply extended, and the boards with which this is done are called “fillies”.

There are quite a few designs of rafter systems. First of all, they are divided into two groups - with layered and hanging rafters.

With hanging rafters

These are systems in which the rafter legs rest only on the external walls without intermediate supports ( load-bearing walls). For gable roofs, the maximum span is 9 meters. When installing a vertical support and a strut system, it can be increased to 14 meters.

The good thing about the hanging type of gable roof rafter system is that in most cases there is no need to install a mauerlat, and this makes the installation of rafter legs easier: there is no need to make cuts, just bevel the boards. To connect the walls and rafters, a lining is used - a wide board, which is attached to studs, nails, bolts, crossbars. With this structure, most of the thrust loads are compensated, the impact on the walls is directed vertically downwards.

Types of rafter systems with hanging rafters for different spans between load-bearing walls

Gable roof rafter system for small houses

There is a cheap version of the rafter system when it is a triangle (photo below). Such a structure is possible if the distance between the external walls is no more than 6 meters. For such a rafter system, you can not calculate the angle of inclination: the ridge must be raised above the tie to a height of at least 1/6 of the span length.

But with this construction, the rafters experience significant bending loads. To compensate for them, either rafters of a larger cross-section are taken or the ridge part is cut in such a way as to partially neutralize them. To give greater rigidity, wooden or metal plates are nailed on both sides at the top, which securely fasten the top of the triangle (also see the picture).

The photo also shows how to extend rafter legs to create a roof overhang. A notch is made, which should extend beyond the line drawn from the inner wall upward. This is necessary to shift the location of the cut and reduce the likelihood of the rafter breaking.

Ridge knot and fastening of rafter legs to the backing board when simple version systems

For mansard roofs

Option with installing a crossbar - used when. In this case, it serves as the basis for lining the ceiling of the room below. For reliable operation systems of this type, the crossbar cut must be hingeless (rigid). The best option- half frying pan (see picture below). Otherwise, the roof will become unstable to loads.

Please note that in this scheme there is a Mauerlat, and the rafter legs must extend beyond the walls to increase the stability of the structure. To secure them and dock them with the Mauerlat, a notch is made in the form of a triangle. In this case, with an uneven load on the slopes, the roof will be more stable.

With this scheme, almost the entire load falls on the rafters, so they need to be taken with a larger cross-section. Sometimes the raised puff is reinforced with a pendant. This is necessary to prevent it from sagging if it serves as a support for ceiling cladding materials. If the tie is short, it can be secured in the center on both sides with boards nailed to the nails. With a significant load and length, there may be several such belays. In this case, too, boards and nails are enough.

For large houses

If there is a significant distance between the two outer walls, a headstock and struts are installed. This design has high rigidity, since the loads are compensated.

With such a long span (up to 14 meters), it is difficult and expensive to make the tie in one piece, so it is made from two beams. It is connected by a straight or oblique cut (picture below).

For reliable joining, the connection point is reinforced with a steel plate mounted on bolts. Its dimensions must be larger than the dimensions of the notch - the outer bolts are screwed into solid wood at a distance of at least 5 cm from the edge of the notch.

In order for the circuit to work properly, it is necessary to make the struts correctly. They transfer and distribute part of the load from the rafter legs to the tie and provide structural rigidity. Metal pads are used to strengthen connections

When assembling a gable roof with hanging rafters, the cross-section of lumber is always larger than in systems with layered rafters: there are fewer load transfer points, therefore each element bears a greater load.

With layered rafters

In gable roofs with layered rafters, their ends rest on the walls, and middle part rest on load-bearing walls or columns. Some schemes push through the walls, some don't. In any case, the presence of a Mauerlat is mandatory.

Non-thrust schemes and notch units

Houses made of logs or timber do not respond well to thrust loads. For them they are critical: the wall may fall apart. For wooden houses The rafter system of a gable roof must be non-thrust. Let's talk about the types of such systems in more detail.

The simplest non-thrust rafter system diagram is shown in the photo below. In it, the rafter leg rests on the mauerlat. In this version, it bends without pushing the wall.

Pay attention to the options for attaching the rafter legs to the Mauerlat. In the first, the support area is usually beveled, its length being no more than the section of the beam. The depth of the cut is no more than 0.25 of its height.

The top of the rafter legs is laid on the ridge beam, without fastening it to the opposite rafter. The structure turns out to be two pitched roofs, which in the upper part are adjacent (but not connected) to one another.

The option with rafter legs fastened at the ridge part is much easier to assemble. They almost never push against the walls.

To operate this scheme, the rafter legs at the bottom are attached using a movable connection. To secure the rafter leg to the mauerlat, one nail is driven from above or a flexible steel plate is placed from below. See the photo for options for attaching rafter legs to the ridge girder.

If you plan to use heavy roofing material, it is necessary to increase the load-bearing capacity. This is achieved by increasing the cross-section of the rafter system elements and strengthening the ridge assembly. It is shown in the photo below.

Reinforcing the ridge assembly for heavy roofing material or for significant snow loads

All of the above gable roof schemes are stable in the presence of uniform loads. But in practice this practically never happens. There are two ways to prevent the roof from sliding towards a higher load: by installing a screed at a height of about 2 meters or by struts.

Options for rafter systems with contractions

Installing contractions increases the reliability of the structure. In order for it to work properly, it needs to be secured to them with nails at the places where it intersects with the drains. The cross-section of the timber for the scrum is the same as for the rafters.

They are attached to the rafter legs with bots or nails. Can be installed on one or both sides. See the figure below for attaching the screed to the rafters and ridge girder.

In order for the system to be rigid and not “creep” even under emergency loads, it is enough in this option to ensure rigid fastening of the ridge beam. In the absence of the possibility of its horizontal displacement, the roof will withstand even significant loads.

Layered rafter systems with struts

In these options, for greater rigidity, rafter legs, also called struts, are added. They are installed at an angle of 45° relative to the horizon. Their installation allows you to increase the span length (up to 14 meters) or reduce the cross-section of beams (rafters).

The brace is simply placed at the required angle to the beams and nailed on the sides and bottom. An important requirement: the strut must be cut accurately and fit tightly to the posts and rafter leg, eliminating the possibility of it bending.

Systems with rafter legs. The top is a spacer system, the bottom is a non-spacer system. The correct cutting nodes for each are located nearby. Below are possible strut mounting schemes

But not in all houses the average load-bearing wall is located in the middle. In this case, it is possible to install struts with an angle of inclination relative to the horizon of 45-53°.

Systems with struts are necessary if significant uneven shrinkage of the foundation or walls is possible. Walls can settle differently on wooden houses, and foundations can settle on layered or heaving soils. In all these cases, consider installing rafter systems of this type.

System for houses with two internal load-bearing walls

If the house has two load-bearing walls, install two rafter beams, which are located above each of the walls. The beams are laid on the intermediate load-bearing walls, the load from the rafter beams is transferred to the beams through the racks.

In these systems, a ridge run is not installed: it provides expansion forces. The rafters in the upper part are connected to one another (cut and joined without gaps), the joints are reinforced with steel or wooden plates, which are nailed.

In the upper non-thrust system, the pushing force is neutralized by the tightening. Please note that the tightening is placed under the purlin. Then it works effectively (top diagram in the figure). Stability can be provided by racks, or joints - beams installed diagonally. In the spacer system (in the picture it is below) the crossbar is a crossbar. It is installed above the purlin.

There is a version of the system with racks, but without rafter beams. Then a stand is nailed to each rafter leg, the other end of which rests on the intermediate load-bearing wall.

Fastening the rack and tightening in the rafter system without a rafter purlin

To fasten the racks, 150 mm long nails and 12 mm bolts are used. Dimensions and distances in the figure are indicated in millimeters.

In order for a constructed building to last for more than one year, it needs both reliable foundation, as well as a strong roofing system that can withstand the vicissitudes of the weather. The roof must withstand heavy loads with dignity: heavy snowfalls, sharp gusts of wind, heavy downpours. The roof truss system is best suited for this.

Roof trusses and its types

The rafter system is the basis of the roof, which focuses on the load-bearing elements of the structure and also serves as a frame for various types of roofing materials: insulation, waterproofing, various coatings.

The dimensions and design of the rafters depend on:

• purchased material;
• size of the building;
• house dimensions;
• building materials for rafters;
• individual customer preferences;
• roof loads relevant for a particular region.

The rafter system has:

• sheathing - beams laid perpendicularly on the rafter legs;
• ties that absorb tensile forces;
• wooden racks located in a vertical position;
• mauerlat - a beam, the installation of which is carried out along the wall, the rafters rest on it;
• rafter legs are a kind of wooden beams that bear the main load of the roof.

Each of the above factors is very important, since it is necessary to understand what type of rafter system will be optimally suited for a particular situation.

When it comes to low-rise buildings, wood structures are the most common. In many cases, three types of rafter trusses are used: hanging rafters, layered rafters and a mixed rafter system.

Characteristics of hanging rafters

Hanging rafters are the most elementary type of rafter systems, their characteristics:

If the roof of the house has a complex structure, the types of rafters can be alternated. For example, if there are supports or a middle main wall, layered rafters are installed, and if there are no such elements, hanging rafters are installed.

Features of layered rafters

For a layered rafter system, the house must be additionally equipped with a load-bearing wall located in the middle. Layered rafters are distinguished according to the following characteristics:

The design of the combined system is the most complex, since it includes parts of two other types of rafters - hanging and layered. It is used for mansard roof. The walls of the rooms located on the second floor are formed by vertical supports; these supports also serve as intermediate supports for the rafter beams.

The part of the rafters that connect one end of the racks functions as a crossbar for the slopes located on the side, and for the upper part of the structure they are a tie.

At the same time, the horizontal beams perform the following functions: for the upper slopes - the Mauerlat, for the side slopes - the ridge beam. To increase the strength of the roof, struts are installed that connect the side slopes and vertical posts.

The combined sling system is the most complex and time-consuming to manufacture, but these shortcomings are fully compensated by the increase in the load-bearing qualities of the roof in the absence of unnecessary supports, especially when there is a need to cover significant spans in the building.

You can increase the load-bearing qualities of the roof using a mixed rafter system

Roof trusses for various roof types

When constructing a certain building, rafter systems of one type or another are necessarily used, and the type of roof will completely depend on the design of the future structure.

Rafter truss for gable roof

Gable roofing is a common roof construction for residential buildings that have no more than three floors. Preference is given to this design due to technical characteristics the inclined shape of the rafter system, and also due to the fact that installation work is carried out easily and simply.

The rafter system consists of two pitched roof includes two rectangular inclined planes. The upper part of the building from the end side resembles a triangle. The main components of a gable roof are the mauerlat and rafter legs. In order to properly distribute the load across the rafters and walls, struts, crossbars and racks are installed, thanks to which you can create a durable, rigid, elementary and lightweight structure for installing a structure for a gable roof.

A gable roof is considered the simplest roofing system; it is used for residential buildings of no more than three floors

On top of the rafters you can install sparse or solid sheathing, and then attach it to it bitumen coating, shingles or some other type of material. The rafters and the sheathing itself are usually made of beams or boards, which are fastened with nails, bolts or metal fasteners. Metal profiles can be used as rafters, thereby covering significant spans. There is no need to use extra racks and struts.

The installation of a rafter system for a gable roof allows you to evenly distribute the entire existing load along the perimeter of the building. The lower ends of the system focus on the Mauerlat. They are fixed with fasteners or metal brackets. By the angle of inclination of the rafter bars, you can determine at what angle the roof slopes will be inclined.

The rafter system for a gable roof allows you to evenly distribute the load from the roof along the perimeter of the building

Rafter system for hip roof

When arranging a system for a hip roof, installation will be required different types rafters:

• narozhniki (short);
• lateral;
• hip main;
• obliques (diagonal elements that form a slope in the shape of a triangle).

The rafter legs, located on the side, are made of boards, and they are mounted identically to the parts of a traditional pitched roof with a layered or hanging structure. Hip main rafters are layered parts. For splices, boards or bars are used, attached not only to the Mauerlat, but also to the diagonal beams.

To install this type of structure, the angle of inclination, as well as the cross-section of the slanting beams, are accurately calculated. The dimensions of the parts also depend on the span length.

To prevent the hip roof from deforming from heavy loads, you should accurately calculate the angle of inclination of the diagonal beams for the rafters

Maintain symmetry when installing diagonal beams for rafters, otherwise the roof will deform under significant load.

Rafter system for a sloping roof

A broken roof is a structure with rafters that consist of several individual elements. Moreover, they should be located at different angles relative to the horizon. And since the bottom rafter part is located almost vertically, the attic space of the building receives additional space, thanks to which it can be used as a living space. The installation of this type of roof is carried out during the construction of a four- or gable rafter structure.

Calculate four-slope system rafters are needed by professionals, but you can make a gable sloping roof yourself, since its installation is very simple. To do this, it is necessary to install a support frame, which should consist of purlins and racks. Horizontal parts are fixed with hanging rafters. But the supports of the sloping roof are secured to the mauerlat with the shortened legs of the rafters.

The assembly of rafters for a sloping gable roof can also be carried out by non-professionals, since the installation of such a roof is very simple

"Cuckoo" in a roof truss

The so-called cuckoo on the roof is a small ledge that is located on the attic floor. There is a window here for better illumination of the attic room. The installation of the “cuckoo” is carried out carefully, while monitoring the parameters of the entire structure: depth of cut, angle of inclination and other factors. However, before this, the necessary measurements are made.

The first stage of work begins with the installation of the Mauerlat (beam with a cross-section of 10x10 cm, which is needed to support the slings). The rafter system acts as a skeleton for roofing material. To impart rigidity to the structure, spacers are used, which are mounted between the two legs of the rafters.

After the installation of the roof truss is completed, sheathing is laid, the type of which depends on the roof covering purchased. Installation of the sheathing is done continuously or with a certain step. Boards, OSB and plywood sheets are usually used for it. In addition, the installation of roofing material must be identical throughout the entire roof.

The main difficulty during installation similar system rafters are the location of the internal corners. Snow can accumulate in these places, which means the load will increase, which is why a continuous sheathing is made.

A “cuckoo” on the roof is a small protrusion on the attic floor, under which there is an additional window.

Chalet roof rafter truss

The peculiarity of this design is that the canopies and overhangs are moved outside the house. In addition, there must be rafters and roof beams extending up to three meters on the sides of the building. Each of these elements is secured with a bracket to the wall of the building in the lower part. Next, tie the edges of the beams. They serve as a support for covering the roof of the building.

But when creating large overhangs, it is necessary to install the reinforced belt in parallel with the installation of studs for the Mauerlat. It is necessary to make anchors that help secure the consoles. In this case, the rafters will be perfectly fixed with anchors and, in addition, with mortises.

To carry out the side cornices, a ridge beam is made, after which beams are placed at the level of the mauerlat, which must be identical to the length of the ridge. The truss, and subsequently the building materials for the roof, rest on these structural details.

When designing a building, the angle of the chalet roof is calculated based on the characteristics of the local climate and other factors. With a slope angle of about 45°, the load from snow is not taken into account, since with this option it will not linger on the roof. At the same time, the flat roof will withstand the load from snow, but it is necessary to install a reinforced roof truss. Before installing the chalet roof, a building design is prepared, because the originality of the roof itself, as well as the long eaves and overhangs, oblige this.

A chalet-style roof is characterized by canopies placed several meters outside the house

Rafter truss designed for soft roofing

Soft roofing is made in various ways, but there are technological methods for its construction General characteristics. Initially, you need to prepare. When arranging a roof for a house made of foam concrete or other material, first install a mauerlat, then in the upper crowns of the building they make cuts for the ceiling beams in increments of up to one meter. The distance between the boards is calculated based on the type of rafter structure.

1. Install individual parts of the rafter system. To completely eliminate the risk, the rafter boards are attached to the ground with screws. After the roof truss is created, it is raised to the top of the building.
2. All elements of the rafters are secured to the ceiling, internal boards, jibs, and crossbars. Further, this base for the roof will become a single whole structure.
3. The next stage is the sheathing, which is installed under the soft roof with small gaps or no gaps at all. Gaps of no more than 1 cm are allowed. Quite often, leveling plywood is installed on top of the boards. Its sheets are laid according to the method brickwork. The resulting joints are not aligned with the gaps between the plywood and the board.

If the length of the sheathing boards is not enough, then the joints of the parts must be located in different places. In this way, you can correctly distribute areas that have been weakened.

Self-production of the rafter system

Before the installation of the rafter system begins, the mauerlat must be secured to the longitudinal walls with anchors. Next you need to decide on the required leg section for the rafters, depending on the distance and their length. If there is a need to increase the length of the rafters, then connect them with various fasteners.

When using different insulation, you need to choose the ideal distance between rafter elements in order to reduce the number of thermal insulation scraps.

Installation of the rafter system must be done in the following order:

1. A template is made according to which the truss is assembled. Take 2 boards corresponding to the length of the rafters and connect them together at just one edge with a nail.

   A template for rafters called “scissors” will help you quickly assemble the entire roof rafter system

2. The result is a design called “scissors”. Its free edges are placed on supports at the points of contact between the rafter legs. The result should be the final angle, that is, the angle at which the roof slope will be inclined. It is fixed with several long nails and transverse boards.
3. A second template is made, thanks to which the cuts are installed on the rafters. It is made from plywood.
4. Special mounting cuts are cut on the rafters (a prepared template is used for these purposes) and connected at an angle of inclination of the slope. You should end up with a triangle going up the stairs to the roof. Next, it must be attached to the Mauerlat.
5. Initially, two side gable rafters are installed. Their correct installation in the vertical and horizontal planes occurs due to temporary struts attached to the rafters.

   For correct installation of the entire rafter system, the first pair of rafters is installed on the roof

6. A cord is stretched between these tops of the rafters. It will indicate the future ridge and the level of other rafters located in the gap.
7. Raise and install the remaining rafters at the initially calculated distance, which should be at least 60 cm from each other.
8. If a bulky rafter structure is envisaged, then it is additionally strengthened with struts, supports, and so on.

   The bulky structure of the rafters is additionally strengthened with struts and supports

9. A ridge beam is installed on special supports, to which not only short, but also diagonal and intermediate elements of the rafters are attached.

   Proper fastening of the ridge beam ensures the reliability of the entire rafter system

Typical components of a standard rafter system

The strength of the rafter structure depends on the ideally selected section of the boards, as well as on high quality rafter nodes. The connection of parts for the roof structure is done according to established rules.

The main typical units in the rafter system:

• rafter support assembly on the mauerlat;
• ridge;
• unit for combining the top ties and the entire rafter system;
• securing the strut, rack, as well as rafters and beams.

After the design of the rafter system has been chosen, it is necessary to draw up a plan in which to highlight all the nodes. In each design they are made differently, since it depends on various nuances: the type of roof, its size, angle of inclination.

Rafters made from a profile pipe are a metal structure that is assembled using lattice rods. The production of such farms itself is a very labor-intensive process, but also more economical. To make rafters, paired material is used, and gussets are connecting elements. The structure of the rafters from profile pipes is assembled on the ground, using riveting or welding.

Thanks to such systems, any spans are blocked, but the correct calculation must be made. Provided that all welding work is done efficiently, in the future all that remains is to transfer the structural elements to the top of the building and assemble them. Load-bearing rafters made from profile pipes have many advantages, such as:

Crossbar in the rafter system

Crossbar is a fairly broad concept, but in the case of roofs it has a certain meaning. The crossbar is a horizontal beam that connects the rafters. This element prevents the roof from “expanding.” It is made of wood, reinforced concrete, and also metal - it all depends on the type of structure. And the crossbar serves to distribute the load exerted by the rafter system.

It can be fixed in various places between the legs of the slings. There is a direct pattern here - if the crossbar is fixed higher, then the timber for its installation must be selected with a large cross-section.

There are many ways to fix the crossbar to the rafter system:

• bolts;
• nuts;
• studs with washers;
• special fasteners;
• nails;
• mixed fastenings, when different types of fastenings are used in parallel.

The fastening is available with a mortise or overhead. In general, the crossbar is a design unit, as is the entire system of roof slings.

The crossbar in the rafter system is designed to strengthen the roof structure

Fastening the rafter system

To ensure the reliability of the rafter system, you must first find out how they are attached to the supporting roof and ridge. If a fastening is made to prevent deformation of the roof when the house shrinks, then the rafters are secured on top with a hinge plate or a nut and bolt, and below with a sliding support.

Hanging rafters need a tighter and more reliable fastening in the ridge, so in this case you can use:

• overhead metal or wooden plates;
• cutting method;
• connection using long nails.

In the layered system, the rafter legs are not connected to each other, since they are attached to the ridge girder.

The rafters are attached to the mauerlat using the cutting method, which is made in the rafter leg. Thanks to this fastening method, the roof support will not weaken. Cutting is also done when installing rafters on floor beams. In this case, a cut is also made in the support beam.

Video: how to make rafters with your own hands

Thus, an ideally selected rafter system and their design characteristics will help create the basis for a reliable roof for your home.

The pitched roof of a house consists of a large number of parts, each of which is connected to the others in a special way. This connection is called a roof joint. In this article we will talk specifically about connection nodes, how they are carried out, what technologies are used, what fasteners are used.

Main parts of the roof structure

Before moving directly to the analysis of the topic of the article, it is necessary to indicate what elements (parts) the roof structure consists of. Let's list all the main parts and indicate their purpose.

Mauerlat. This is a beam that is laid on the walls of the house located along the perimeter of the building. The purpose of the Mauerlat is to evenly distribute the loads coming from the rafter system. After all, if there is no Mauerlat, then each rafter will put pressure on the wall pointwise. And it is in this place that the destruction of the wall structure will occur.

Rafter legs. They are made either from boards with a thickness of at least 50 mm, or from timber. Rafters are the basis of the roof; they form the slopes and bear all the loads acting on the roof structure.

Ridge run. This is the topmost beam, installed horizontally. Its purpose is to support the upper ends of the rafter legs. It is this that forms the ridge of the roof.

These are the three main elements of the roof, which will be discussed further. Of course, these are not all the details of the roof, and we cannot say that others are less important. It’s just that these three elements form the structure itself. The only thing that needs to be added is that some roof designs do not have a ridge girder. The rafters simply rest against each other with their upper ends. This type of rafters is called hanging, and with a ridge girder, layered.

So that the roof structure is as reliable as possible, it is necessary that the roof components are correctly connected. In this case, it is necessary to take into account the strength effective loads and their direction.

How to connect elements of a roof structure

More recently connection of nodes wooden roof carried out using cuts. That is, they cut the elements of the roofing structure in order to connect them along one fairly wide plane. Therefore, so that the roof parts do not reduce their strength characteristics, as well as load-bearing capacity, they were selected with a sufficiently large cross-section. And this is not economical. That is, the larger the cross-section of lumber, the more expensive it is.

Today, technologies for fastening components and parts of roofing structures have changed dramatically. To do this, use bolts, dowels or perforated metal profiles. The latter are made of galvanized steel, which makes it possible to use fasteners for a long time without losing their quality. At the same time, manufacturers offer a fairly wide range of them for each type of unit. The photo below shows some of these fasteners.

It should be noted that perforated profiles gradually replaced all other types of fasteners due to their strength, reliability and ease of fastening operations. After all, to do this, you just need to install the profile in the required place and fasten it to various parts with wood screws or ruff nails.

Let's now look at how to fasten parts roof structure to each other. In principle, there are two types of connections: Mauerlat-rafters, rafters-ridge girder. The remaining parts are connected parallel to these joints. He will also talk about them.

Connection of Mauerlat and rafters

There are actually a huge number of fastening options, from ordinary nails to perforated profiles. For example, the photo below shows an option where ordinary wire is used as fasteners. That is, a through hole is made in the rafter itself, into which a wire with a diameter of 6 mm is inserted. A hole is also made in the Mauerlat or in the floor beam.

Then the ends of the wire are pushed into this hole and twisted, pressing the rafter leg to the Mauerlat. The connection is actually strong and reliable, but the process is labor intensive.

Instead of wire you can use metal tape 3 mm thick. It is simply wrapped around the two elements being connected and secured to them through the strip with self-tapping screws, often with nails. In the latter case, there is no need to drill through holes in the metal. note that in the lower photo the fastening is carried out to reinforced belt anchor, which increases the strength and reliability of the connection.

On our website you can find contacts of construction companies that offer the service of calculation and turnkey roofing work of any complexity. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.

The next type of fastening is a perforated corner made of galvanized steel. Most convenient option, but as reliable as possible. To do this, the corner is simply installed so that with its mounting shelves it is pressed tightly against the plane of the Mauerlat and the rafter leg. Fastening is carried out with self-tapping screws or nails.

Attach corners It is possible not only with self-tapping screws or ruff nails. There is another more reliable option that uses bolts. True, holes will have to be made for them, which increases the time required for this type of work. But in this case, quality comes first. The photo below shows just such a mounting option. Please note that the corner is attached to the mauerlat with self-tapping screws, and to the rafter leg with a bolt. In this case, one bolt is used to connect two corners located at opposite ends of the rafters.

And another mounting option - on the slider. This special type fastening element consisting of two parts. One is attached to the mauerlat, the second to the rafter leg. In this case, both parts are not tightly connected to each other. This was done specifically so that the rafters could move relative to the Mauerlat during thermal expansion of the lumber. This means that there will be no loads that act on the junction of two roof parts. The photo below shows this connection option.

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Connection of rafters with ridge girder

The second main unit of a wooden roof is joint between rafter leg and ridge beam. Actually a ridge knot rafter roof it is very complex because it is where two rafter legs and a beam are joined. In this case, all elements are located in different planes, meaning rafters and beams. This means that to connect them you will have to use more than one fastening element.

To connect rafters to each other they use perforated plate. There are two of them, installed on different sides of the rafter legs to increase strength and reliability.

Perforated corners connecting the rafters to the Mauerlat. There are four of them, two for each rafter leg, installed on different sides.

It should be noted that fastenings can be carried out not only with self-tapping screws or nails. Often masters use bolts for connection paired fasteners.

Pay attention to the different type of fastening. Only corners are used here. This option is used if a 50 mm thick board is installed as a ridge beam.

Another interesting option fastening the rafter legs to the ridge span, for which special perforated profiles of complex shapes. Essentially, these are brackets into which the rafter leg is inserted. The bracket not only holds the parts together, it supports the rafter, reducing the load on its end.

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Pay attention to all of the above options for connecting the rafters to each other. They clearly show that the ends of the rafter legs are joined tightly to each other, for which they have to be filed at a certain angle. You can do without filing if you use a complex fastening lock consisting of several plates that are connected with bolts. In the photo below this connection option is clearly visible.

Connection of hanging rafters

The rafter system of this type differs from the layered one in that it does not have ridge girder. That is, the rafter legs in the upper part (ridge) rest against each other. To prevent them from moving apart in different directions, the rafters are connected to each other by a horizontal tie. The latter is a board located at any distance in height: above, below or in the middle.

It should be noted that hanging rafters They are not assembled separately on the roof. Trusses are assembled from them on the ground, which are installed in finished form on the roof of the house. In this case, all elements of the truss are connected to each other by perforated plates.

Video description

In the video, the master explains how to assemble a roof truss using perforated plates and nails:

Other types of knots

As mentioned above, there are many details in a roof structure. Therefore, we will tell and show a few more important connection points.

If the span of the house is more than 6 m, then a rack is installed under each rafter, which itself must rest either on the concrete base or on the floor beam. In this case, the connection of the rack with the rafter leg is carried out using ordinary boards, as shown in the photo below. Although you can use perforated metal plates.

They are also installed under the ridge beam vertical support posts, which are fastened together with perforated plates. But some roofing structures use a completely different approach to solving the installation of a ridge girder. Under the beam, jibs made of bars are mounted, which are secured to the ridge with special fasteners made of metal. The photo below shows one of the options for this type of fastener.

Very often, when constructing a rafter system, it becomes necessary to lengthen the rafters themselves. This is not difficult to do, and craftsmen use several technologies where they use various additional fasteners.

Video description

The video shows one of the options for lengthening the rafters:

Roofing structures come in several varieties of their forms. Almost all models contain a large number of identical elements. But among them there is one design that differs significantly from the others. This hip roof . Its distinctive feature is that the rafters are connected by their upper edges to one point, which is called a ridge knot.

So, in order to connect the rafter legs to each other, you need a support to which they are attached. There are several ways to ensure high node reliability. The photo below shows one of them, which uses perforated mounting metal profiles U-shaped.

Conclusion on the topic

In fact, we have considered only a small part of the connecting nodes for fastening the roof truss system. But even with their example, the variety of parts and components becomes clear. That is, the roof structure is a complex system, consisting of a large number different elements and parts that are connected to each other in different ways.

December 12, 2017
Specialization: facade finishing, interior decoration, construction of cottages, garages. Experience of an amateur gardener and gardener. We also have experience in repairing cars and motorcycles. Hobbies: playing the guitar and many other things that I don’t have time for :)

Any roof is subjected to various loads every day, as it is affected by wind, precipitation, and also holds the roofing covering. In order for the roof to cope with all these loads for many decades, it must be properly designed. Therefore, I recommend that everyone who wants to do construction on their own understand what parts and components of the rafter system exist, and what function they perform.

Frame elements

All parts of rafter systems can be divided into two types:

• Basic. These parts form the roof frame, called the rafter system. Not a single roof can do without them;
• Additional. This group includes elements that may be present in some types of roofs, while others do without them. The purpose of the additional elements is to increase the rigidity and strength of the frame.

Main nodes

So, the main components and parts of the rafter system include the following elements:

• Mauerlat. This, one might say, is the basis of everything roofing systems, since the rafter legs rest on the mauerlat. Its design is extremely simple; in fact, it is an ordinary beam (log in log houses) laid along the perimeter of the walls. Its task is to evenly distribute the load from the roof onto the walls of the building.

It must be said that on a gable roof the mauerlat can be located not along the perimeter, but only on the side walls, since on the end walls there are gables, which are a continuation of the wall;

• Rafter legs (hereinafter SN), or simply rafters. These parts are the load-bearing element that forms the slope and its angle of inclination. They take on wind and snow loads, as well as the weight of the roofing material, and transfer them to the walls through the Mauerlat and other elements.

Rafters can be side (main), diagonal (installed at the junction of the hip roof slopes) and shortened (diagonal rafters rest on the Mauerlat);

• Roof trusses. They are formed by paired (reciprocal) rafter legs. It must be said that trusses are present on all pitched roofs except single-pitched ones, since they do not have reciprocal rafters;
• Ridge knot. It is the top of the truss, i.e. formed by the junction of two CHs. The ridge unit, like the trusses themselves, is absent only on shed roofs.

That's all the main components wooden structures roofs that form them.

Additional

Additional details include:

• Run. This is a horizontal beam that connects all CHs within one slope;
• Ridge run. It is the same horizontal beam as a regular purlin, but which runs in the ridge unit, i.e. connects simultaneously two legs of each truss.

It must be said that the ridge girder can be installed in several ways - above the joint of the rafters, in the center of the joint, i.e. the legs rest on the purlin, or under the rafters;

• Tightening (crossbar, contraction). It is a beam that connects two response legs, preventing them from moving apart. We can say that tightening removes the thrust load from load-bearing walls;

• Supports. They can support rafters, all types of purlins or tightening. The supports transfer the load to interior walls buildings, columns or ceilings;
• Struts (rafter legs). They are inclined supports, which have the same function as the vertical posts. The only thing is that they support only the legs, i.e. are one of the elements of wooden trusses. The rafter legs transfer the load to the load-bearing elements of the building or to the ceiling;
• Fillies. These elements form the overhang of the slope if the SNs do not extend beyond the walls. Essentially, they prolong CH, i.e. are their continuation.

These are all the elements that make up the frames of pitched roofs.

A few words about the types of systems

So, we have dealt with the knots, now let's look at the main types of rafter structures. There are several of them:

• Single-pitch. As I already said, these structures do not have trusses. The slope angle is formed due to the different heights of the walls on which the SNs are laid, or due to the purlin, which is laid on racks installed on one of the walls;

• Gablesloped. Layered rafters are rafters that are supported by posts or struts that transfer the load to the internal load-bearing elements of the building. The frame of such structures is formed only by trusses, i.e. they do not have diagonal legs.

• Gable hanging. Hanging rafters differ from layered rafters in that they transfer the entire load from the roof only to the outer walls;

• Hip. Unlike gable ones, at the ends instead of vertical gables they have inclined hips, i.e. end slopes. As I said, the hips form diagonal and short legs;

• Broken. They are a gable structure, each CH of which is divided into two parts and located at a different angle. Skates, i.e. The upper legs form a gentle slope, and the lower legs form a steep slope. This design allows you to increase the attic space, as a result of which it can be used as an additional floor.

Typical broken (attic) systems have racks on which the upper and lower SNs rest. The counter posts are connected to each other by tie rods (attic floor beams).

There are also semi-mansard structures, which are essentially ordinary hanging gable roof systems. The only thing is that their fastening with the Mauerlat is usually made sliding (movable), which allows you to increase the deflection of the CH, and thereby reduce the thrust load on the walls.

Despite the fact that the designs of all the above systems are different, they consist of the same parts that we have already become familiar with.

Lastly about fastenings

Finally, I propose to consider how connections are made between the main components such as:

• Rafter/mauerlat;
• Ridge knot.

The remaining parts do not deserve special attention, since their joining most often occurs by sawing down the mating area (to increase the area of ​​contact of the parts) and laying on steel plastic/corners, which are fixed with screws. Sometimes fasteners are not even used, i.e. the parts are attached to each other with screws without any overlays.

Connection of rafters and mauerlat

The attachment point for the leg and the power plate can be made in several ways:

• Using grooves. In this case, grooves are cut out under the Mauerlat into which the CH is inserted. Then it is additionally attached to the Mauerlat on both sides with a steel angle;

• Tooth and thorn. This method is usually used to attach the CH to the tie. Its principle is based on the fact that a tenon is selected at the end of the sawed-down CH, and a groove is selected at the tightening. In addition, the leg itself rests on the so-called tooth, i.e. a protrusion in the tightening that takes on the spacer load.

It must be said that recently the tooth-and-spike type fastening is rarely used, since it is much easier to use special fasteners, the same corners and plates;

• By washing it down. In this case, the SN is sawed down so that a right angle is formed at the junction with the Mauerlat, as a result of which the rafter not only rests on the beam, but also rests against its side surface, thus transmitting the spacer load. It must be said that instead of sawing, you can fasten a block, as shown in the diagram below.

Connection of rafters and ridge girder

The connection between the CH and the purlin can be made as follows:

• Using a groove. In the CH, two counter cuts are made, as a result of which, after the junction of the rafters, a groove is formed for the ridge girder;
• Hard pinching. The principle is based on the fact that puffs are installed under and above the purlin;

• I started drinking. This is the simplest and most common method, the principle of which is based on sawing down the CH for maximum fit to the beam. In this case, fixation is carried out with a steel angle.

Here, perhaps, are all the main nuances of assembling rafter systems.

Conclusion

We have found out what parts rafter systems consist of, what types they come in and how their main elements are connected. If I missed any points or something is unclear to you, write comments, and I will be happy to answer your questions.

December 12, 2017

If you want to express gratitude, add a clarification or objection, or ask the author something - add a comment or say thank you!

The roof is one of the main elements of a residential building. Both the comfort inside the house and the service life of the building depend on how well its installation is done. The roof plays a particularly important role in multi-storey residential buildings, total area which exceeds several hundred square meters.

What is the roof of a house made of?

The roof of a house is its uppermost part, used to protect the load-bearing elements and living space of the building from precipitation. In addition, it is a thermal insulation barrier that reduces the flow of heat from residential premises and protects the structure of the building from overheating.

The roof not only protects the under-roof space from precipitation, but also helps to retain heat in living spaces

Depending on the functionality of the building and its design, the roof may have a different appearance. The design and type of roof determines its ability to remove snow and rainwater from its surface. The space under the roof frame is often used as a living or utility room.

Any roof has a standard design, which is determined by the technology and temperature conditions in the region where the structure is being built. To better understand this topic, let's look at the structural elements of the roof in more detail.

Roof frame

The roof frame is a load-bearing and supporting element responsible for its strength characteristics. The quality of the frame directly affects the service life of not only the roof itself, but also the structure as a whole.

As a supporting structure for the roof in private houses, a rafter system is usually constructed from wooden beams.

Depending on the design, the roof frame may look like this:

• rafter system is the most common type of roofing frame, most often used for the construction of roofs of commercial and residential buildings from timber, brick and foam blocks. It is divided into hanging and layered structures. The former are used in buildings where only external walls are load-bearing, and the latter - in houses with internal load-bearing partitions that can be used as additional supports;
• support system from steel beams- used for erecting roofs over industrial buildings. Unlike wood, metal allows you to create longer, and most importantly, solid beams without mates along the length. This, in turn, significantly increases the load-bearing capacity of the roof structure. Metal is non-flammable material, which makes the roof safer and more durable;
• flat concrete frame - represents reinforced concrete slabs, laid on top of load-bearing walls at a certain angle. Most often used to create roofs over public buildings small size and storage facilities.

To implement any special project, different types of frames can be combined or used in a modified form. For example, Roof truss systems are often constructed from wood and metal simultaneously, which in one place of the structure makes the roof stronger and more reliable, and in another it does not weigh down the load-bearing partitions, thereby reducing the overall load on the foundation. This option can be used when one part of the house is located on a sloping slope. Lightening the roof structure will avoid excessive load on a columnar or pile foundation, which are most often used in such cases.

Video: gable roof frame for metal tiles

Roofing pie

Roofing pie is a technology for laying roofing, steam and thermal insulation in a certain sequence. Correct sequential installation ensures that each technological layer will perform its strictly defined function.

For example, if the waterproofing material is laid incorrectly (under the thermal insulation), then moisture will enter the insulation, which will inevitably cause its damage and loss of the characteristics declared by the manufacturer.

All layers of the roofing pie must be laid in a strictly defined sequence so that each coating can perform its assigned functions

A typical roofing pie consists of the following technological layers:

• roofing material - a facing covering responsible for appearance the front surface of the roof and protecting the sheathing and underlying layers of the roofing pie from water, dirt and foreign objects;
• sheathing is a supporting structure necessary for fastening the roofing material. Depending on the type of finishing coating used, the lathing can be continuous or sparse;
• waterproofing is a mechanically strong waterproof material that protects the insulation from getting wet. For this purpose, bitumen roll coatings, anti-condensation membranes or liquid mastics can be used. The specific method of waterproofing is selected based on the type of roof and insulation;
• thermal insulation - basalt roll or slab insulation, polystyrene foam, expanded polystyrene, etc. Thermal insulation material must have a low thermal conductivity coefficient, which guarantees long-term maintenance of the required climatic conditions in the house at any time of the year;
• vapor barrier is a multi-layer membrane that protects the insulation and other elements of the roofing pie from the penetration of warm, moist air from the interior.

The sequence of laying the technological layers of the roofing pie is determined by the type of roof being installed and the materials used for this. The most common option is when waterproofing is laid under the roofing, then a layer of thermal insulation material is placed, and a vapor barrier membrane is installed under it.

Main roof components

The junction of the roof and the wall, if the building has complex shape, as well as the contact points of the roofing pie and the outer face covering to the external parapet are no less important than the roof structure itself.

The integrity and durability of the structure being built depends on the quality of their execution, since the use low-quality materials or non-compliance with the connection technology can cause moisture and precipitation to penetrate under the roofing.

Roof connection nodes

The place or junction of the roof and the wall is a connecting seam, which is treated with waterproofing and protective materials. The junctions are the most vulnerable areas of any roof, since wet debris constantly accumulates at the junctions of its elements.

If the junction is poorly insulated, then moisture quickly gets under protective material and roofing. Constant absorption of moisture into the insulation will certainly lead to a loss of its technological qualities.

All junctions of the roof with the structural elements of the building must be carefully treated with waterproofing materials to prevent moisture from entering the under-roof space

In addition, the junction points are subject to temperature deformations due to freezing and thawing of water - this increases the risk of leaks. To avoid problems during roof operation, the technology for insulating junctions is thought out in advance. It is taken into account as temperature regime in the region where the structure is being built, and the average level of precipitation throughout the year.

Depending on the type of roofing, junction points are arranged in various ways:

• metal roofing - junctions are made with a small gap necessary for ventilation of the roofing pie. A metal strip or apron made of galvanized steel is used as a protective element. The apron is attached directly to the adjacent wall at a height of 200 mm. Before installing it, the groove in the wall is treated with frost-resistant sealant;
• various types of tiles - the junction of the wall and the roofing is protected with corrugated aluminum tape. Due to its small thickness, the tape exactly follows the profile of the roofing covering. To seal the seam, hot bitumen mastic is used, which is poured directly along the seam line;
• bitumen roll materials - the junction can be made according to different technologies. The most common method is to lay the covering with an overlap on a vertical surface. In this case, the material is pressed against the lath, which is pre-treated with sealant. The amount of overlap, as a rule, is at least 20 cm.

Cornice unit

The cornice covers and protects the lower part of the roof, the roofing pie, the rafter system and other elements from moisture. In fact, the finishing of the eaves assembly directly affects the service life of the mauerlat and roof truss system, since if the cladding is poorly executed, moisture flowing down the roof covering can get into the under-roof space.

To protect against moisture getting into the under-roof space, special metal strips - drips and ventilation strips - are installed on the eaves overhangs.

To install the eaves assembly of a pitched roof, the following sequence of laying protective materials is used:

1. Roofing covering.
2. Countergrid.
3. Roof sheathing.
4. Waterproofing membrane.
5. Dropper.
6. Bracket for fastening the drain.
7. Gutter.
8. Cornice strip.
9. Overhang aero element.
10. Ventilation tape.
11. Double-sided adhesive tape.

The drip cap protects the front board from condensation flowing down the waterproofing film, and cornice strip prevents moisture and precipitation from entering the under-roof space. The overhang aero element serves to create a ventilation gap and protect against birds and large insects from entering under the roof.

Pediment node

The pediment is the end section of the roof, limited by the roof slope and eaves. It protects the roof from moisture and also plays the role of a decorative element.

The pediment completes the roof, but is not its obligatory attribute, since in some types of structures the roof is limited only by the cornice.

Most often, gables are installed on pitched roofs, when various types of tiles, profiled sheets or soft bitumen coatings will be used as roofing.

On the gable side, the under-roof space is protected by a wind board, and then by a gable strip laid on top of the waterproofing layer

The sequence of laying materials when installing a gable unit is as follows (from the outer edge to the under-roof space):

• gable strip laid on top of the roofing;
• waterproofing material;
• wind board;
• sheathing;
• rafter.

When attaching gable strips, you should follow the technology described in the instructions for the roofing. Usually they are mounted from bottom to top from the eaves to the ridge. When using several planks, the overlap should be at least 10 cm.

Valley device

Endova is internal corner roof, formed at the junction of two slopes. In fact, when constructing multi-pitched roofs, the valley is a key structural unit, since precipitation will flow along it. The roof valley always experiences increased loads, so its installation must be carried out especially carefully, in full compliance with the technological requirements established by the manufacturer of the roofing material used.

The arrangement of the valley unit for a pitched roof is carried out using special additional elements that are mounted on a continuous sheathing

A typical version of a valley assembly for a metal roof is represented by the following elements:

• upper valley;
• sealing material;
• roofing;
• lower valley;
• continuous sheathing;
• waterproofing membrane;
• roof truss system.

The valley is usually laid on a continuous sheathing, which is mounted on both sides of the junction of the slopes. When using metal coverings (corrugated sheeting, metal tiles, seam roofing), the main protective element is the lower valley. It is placed under the roofing material and serves as a kind of gutter through which moisture flows into the drainage system. The upper valley in this case is larger decorative element, which covers the entire structural unit and protects it from birds and foreign objects.

Ridge knot

The ridge of the roof is the upper horizontal rib formed by the junction of two slopes. The ridge strip or tile protects the junction of the rafters, thermal insulation and sheathing from moisture and is installed last. Depending on the roof covering, different ridge elements are used.

The installation of the ridge unit is carried out last, when the roofing covering is laid

For example, the design of a ridge unit for a soft roof looks like this (from top to bottom):

• soft ridge tiles;
• roofing;
• underlay carpet;
• roof sheathing.

In some cases, a 40x40 or 50x50 mm ridge block is nailed along the edge, on which the underlay carpet is laid. If you plan to install the roofing yourself, read the instructions for the material - it must contain a diagram of the arrangement of all the main components of the roof.

Parapets around the roof perimeter

A roof parapet is an enclosing structure mounted along its perimeter. Typically, parapets are mounted on flat roofs, but quite often they can be seen on pitched roofs, especially in the residential multi-apartment sector. The main purpose of the parapet is to ensure the safety of the person on the roof. Sometimes such designs are used as a decorative element.

The installation of parapets (SNiP II-26–76) is mandatory for buildings whose height to the roof eaves is more than 10 m, and the slope angle of the slope does not exceed 12 degrees. On steeper roofs, fences are installed at a height of 7 m.

If we consider low-rise private housing, then the installation of parapets is relevant only for houses with a flat roof. For gable or hip roofs, the installation of parapets is optional. But it should be borne in mind that if annual maintenance of the roof covering is planned on pitched roofs, then safety measures must be appropriate.

In private construction, parapets must be installed only on flat roofs

The following materials are used for the manufacture of parapets:

• reinforced concrete blocks;
• brick and foam blocks;
• galvanized metal.

According to SNiP, the height of the parapets must be at least 45 cm. Optimal height is selected based on the architectural features of the building and the personal preferences of the home owner.

The junction of the roofing pie and the parapet is made using hydro- and heat-insulating materials. At the junction of the parapet and the roof, a transition side made of mineralized insulation is laid. To fix the insulation, a special cold mastic is used. Waterproofing is installed with an overlap of 20–25 cm on a vertical surface.

To protect the parapet, a similar waterproofing material is used, which is fixed with an overlap onto the previously laid sheet coming from the roof. A U-shaped galvanized steel box is also installed on top of the insulation.

Additional roofing elements

Additional roofing elements are products designed to connect various components and parts of the roofing covering. In addition, they provide additional functionality and also improve the appearance of the front surface of the roof and the roof as a whole.

Various additional elements make it possible to protect the roof structure from weather influences, preventing the penetration of moisture, dust and debris into the under-roof space. It should be understood that depending on the roof design, the number and need to use additional elements may vary.

A wide range of additional elements are used for metal roofing, protecting its structural components from the penetration of moisture and debris and giving the entire building a finished look

For example, typical additional elements used in the construction of a pitched roof include:

• ridge and valleys;
• adjacency elements;
• strips for cornices;
• end strips;
• corner strips;
• snow barriers;
• adapters;
• gutters.

Before choosing additional elements, you should carefully study the roof design and, based on it, calculate the amount of material required. It is not recommended to save on additional elements, since the safety of the roof structure and roofing pie at the junction points, on the ridge and drains depends on their quality.

Video: roof installation - insulation, ventilation, board selection

Installation of various types of roofing

The design of the roof and roofing pie varies greatly depending on the type of structure. This is due both to the design features of the roof being erected and to the features of the materials used for its construction. For a more detailed description, let's look at the most common types of roofing in more detail.

Warm and cold roof

Warm roofing is a generalized concept that denotes an insulated roof structure. That is, any type of roof can be warm or cold, depending on whether the appropriate hydro- and heat-insulating materials were used during their installation.

If, during the construction of a roof, a standard roofing pie is completely installed, then it is called warm

If we talk about the private sector, then in buildings that will be used for year-round living, insulation is recommended for any type of roof. The most common roof design for private houses is two pitched design, so let’s look at the construction of a roofing pie using its example. The main elements of the roofing pie warm roof are:

The number of layers of insulation is selected individually for each house project. In this case, both the size of the building itself and the possibility of creating a residential attic space, and the temperature regime in the region where construction work is carried out.

Sometimes, if the owner of the house, for example, decided to save on the roof structure or the attic space will not be used as a living space, the roofing can be done without laying thermal insulation material and vapor barrier. This type of roof is called cold. The role of the steam-permeable material will be played by a moisture-resistant vapor barrier membrane. Cold roofs are usually installed in seasonal houses and outbuildings.

Pitched roof with metal coating

A metal roof is usually a pitched structure with a wood rafter system. The type of rafter system is selected based on the location of the load-bearing walls of the building. The use of metal as a roof covering influences the technology of constructing the roofing pie of such a roof.

The most popular roofing material for private residential buildings is metal tiles

The following materials are used for installing a metal pitched roof:

• additional elements - metal ridge, side wind strips, gutter and gutter strips, gutter and other elements installed after installation of the metal covering;
• roof covering - flat sheet material(seam roofing), profiled sheets, metal tiles or other painted metal materials;
• sheathing - edged boards or metal profile elements, fixed in increments of 25–30 cm;
• rafter system - can be made of either thick edged boards or timber, or metal. In private construction, the first option is the most popular due to its availability, ease of installation and lighter weight.

The remaining technological layers of the metal roofing pie are identical to the option described in the section above. It should be noted that the metal coating is especially prone to the formation of condensation on the inner surface, where, despite the presence special protection, still penetrates wet air from home. Therefore, the installation of all ventilation gaps provided by the technology when using a metal roof is strictly necessary.

Waterproofing is made of a moisture-resistant membrane, which is fixed to the roof rafter system, and any slab insulation with a thickness of 5 cm or more is used as thermal insulation.

Video: organizing waterproofing for a metal roof

pyramid roof

A pyramidal or hipped roof is a pitched structure, where each of the four slopes is equal in area, and there is a square at the base of the roof. In fact, each of the four slopes is an isosceles triangle.

In some cases, a pyramidal roof is understood as a structure with any number of slopes - the main thing is that they are the same size. Such roofs look very harmonious and are not similar to other types of roofs.

In terms of its design, the pyramidal roof is made according to the traditional scheme with rafter elements, although it has some features compared to the classic gable version.

The rafter system of a pyramidal roof has a number of design differences from the structure of a standard gable roof

The rafter system of a pyramidal roof consists of the following elements:

• slanted rafters - diagonal beams located at the corners of the structure. Made from timber or double thick boards;
• Mauerlat - the lower horizontal beam necessary for supporting and fixing the diagonal rafters;
• rafter legs (springs) - support bars attached to diagonal rafters. Provide increased strength and rigidity of the structure;
• struts - vertical posts used as supports for rafter legs;
• crossbars are horizontal beams that are mounted at the top of the diagonal rafters. Increases the strength and wind resistance of the roof;
• lie down - horizontal elements at the base of the structure to which the racks are attached.

The general structure of the roofing pie of a pyramidal roof is not much different from the classic version.

1. The rafter system is hemmed with a rough board.
2. The vapor barrier membrane is unfolded and fixed.
3. Insulation of the required thickness is laid on it.

   Insulation boards must be laid so that they fit into the space between the rafters with a noticeable tension and leave no gaps for cold air to penetrate

4. Waterproofing material is laid.
5. A counter-lattice is installed, which additionally secures the waterproofing layer.

   Counter-lattice bars, laid along the rafters, fix the waterproofing film and form the necessary ventilation gap, and the boards of the longitudinal sheathing are used to fasten the roofing covering

6. The longitudinal sheathing is laid.
7. The roof covering is being installed.

   The hipped roof looks very harmonious and gives the house the appearance of a fairy-tale tower

Roof made of SIP panels

SIP panel (from the English Structural Insulated Panel) is a building material in the form of a slab consisting of two external plates of solid material, between which there is a layer of insulation. On one side, the shell of the SIP panel is made from an OSB board, on the other, from a sheet of corrugated board or also from an OSB board. Panels with a metal coating are used as an independent roof covering, OSB products are used as a continuous flooring under a soft roof.

As a rule, polystyrene foam or polystyrene foam of a certain density is used as a heat insulator. Sometimes polyurethane foam is pumped into the space between the plates or polypropylene is installed. Previously, panels were used only as a material for the construction of building frames, but now they are successfully used for the construction of roofs.

Unlike traditional materials, installing SIP panels does not require creating a massive frame

A typical structure of a gable roof made of SIP panels under a soft roof is the following sequence of elements:

• strapping - made of wooden beams with a comb. The size of the beam depends on the size of the panel groove;
• ridge and end rafters - timber of similar size is used for manufacturing. For a skate, you can take a board with a thickness of 5 cm;
• Mauerlat - made of timber from 100x100 to 200x200, depending on the size of the house and the thickness of the walls. It is mounted on the upper ends of the walls to provide support for attaching the trim.

Each SIP panel is laid on the rafters and the nearest horizontal purlins. Next, it is adjusted and treated with a special adhesive mass or frost-resistant polyurethane foam. Upon completion, a suitable size trim is installed in the panel groove. In this case, the harness is also fixed to the Mauerlat and the ridge.

Video: installation of a roof from SIP panels

Semicircular roof

The semicircular roof is a “bent” structure with smooth arch lines. For its construction, a rafter system based on arched lamellas is used.

For their production, a board of the highest or first grade is used, which is steamed to 100 degrees. Due to the absorption of large amounts of moisture, the wood becomes elastic. Special forms are used to bend the workpieces. After shaping, the pieces are glued together and sent for drying.

As a result, the customer purchases a certain set of materials sufficient to manufacture the roof according to a pre-designed project. The assembly scheme is as close as possible to the technology that can be found when installing metal dome roofs.

To install a semicircular roof, special rafter elements made for a specific project are used

The semicircular roof consists of the following elements:

• Mauerlat - lower support beams necessary for fixing the elements of the rafter system;
• lamellas - elements of short length, having an arched shape. They are assembled into a frame using stringers;
• stringers - horizontal elements that are attached between the lamellas when assembling the frame;
• partitions - horizontal beams fixed at the end of the roof. Provide rigidity and strength of the structure.

To assemble the rafter system of a semicircular roof, galvanized fastening strips and self-tapping screws are used. The size of the fasteners is selected for the specific size of the lamellas. The sequence of laying insulation and insulation is completely identical to that described above.

Construction of expansion joints

An expansion joint located on the surface of the roofing is designed to compensate for thermal expansion facing material. In addition, it reduces the resulting stresses due to movement or shrinkage of the roof structure.

The design of expansion joints depends on the size and design of the building. In the case of residential buildings, arranging a seam is necessary when the roof of one building adjoins the wall of another, when materials with different degrees of linear expansion are adjacent, as well as in places where there is a sharp change in temperature inside the room.

To create an expansion joint on a flat roof, a vapor barrier, mineral insulation and bitumen roll coating are used

In private construction expansion joints are installed on flat soft or pitched roofs covered with bitumen roll coatings. They consist of several components:

• vapor barrier - laid without joints under the expansion joint. It is better to use a moisture-resistant vapor barrier membrane;
• space at the point of rupture - in the place where the expansion joint passes, a compressible non-combustible material is placed thermal insulation material. Compressibility is determined according to GOST 17177;
• expansion joint - mineral heat-insulating material is laid over the rupture site so that it overlaps the seam by 15 cm on each side. Hot mastic is used for fixation;
• heat insulator over the seam - for additional stress compensation, mineral insulation, rolled into a tube Ø50–70 mm, is laid on top of the seam.

Laying the roofing covering to protect the expansion joint is done in small sheets, covering the joint by 30–50 cm on each side. More detailed technology for installing expansion joints should be checked with the manufacturers of the roofing material that you plan to purchase.

Roof access device

During operation, the roof and additional roofing elements require periodic inspection, which allows you to prevent problems that have arisen or eliminate problems that have already arisen. To do this, it is advisable to equip the roof with a special exit.

The type of device used depends not only on the roof slope, but also on the size of the attic space. Some types of structures are simply inconvenient to keep in a small space.

Transparent roof hatches are also excellent sources of natural light

To access the roof, the following methods are used:

• roof hatches - already finished goods, which are mounted in pre-prepared holes in the roofing pie. They are a steel or plastic box with a fixed monolithic or transparent hatch. Access to the roof is via a stepladder or ladder;
• hatches with folding ladder - devices combined with attic stairs, which folds into a specially designated space. As a rule, when folded, this type of hatch is no different from the previous one;
• a dormer window is a compromise option when the window is used not only to illuminate the roof space, but also to provide access to the roof. It is highly desirable that roof drains be provided on the roof surface;
• external staircase - welded metal or wooden staircase, which is attached to the wall of the house as needed. If desired, it can be fixed to the surface of the wall, but not all owners of private houses will like this.

Installation of roof hatches is not particularly difficult and is carried out according to the instructions supplied with them. Usually this is a steel box that is fixed to the rafter system using self-tapping screws. In some cases, the box is mounted directly on the mounting foam.

Roof construction is a broad topic that requires careful study of the technology. Especially when it comes to multi-pitched roofs, which have a large number of slope junctions. If you decide to install the roof yourself, carefully study all the available information and only then proceed with the work.