The design of any roofing system is complex process, in which only professionals should participate. When constructing any type of roof, the most difficult and serious stage is the construction of the rafter system.

Today, rafter systems can be of several types. We propose to consider in this article one of the most common types - sliding rafter systems. So, we will look at the main nuances that need to be taken into account during their construction, and also learn about their functions.

The construction of rafters must be approached with great responsibility. If you make any mistake, the structure of the roof may be damaged, which will lead to its destruction. In addition, this may have a negative impact on the building itself.

To build a roofing system correctly, you first need to start preparing its main elements.

Among them are:

• Ridge - the top element of the roof. Based on the first skate made, a mandatory template is made, which will then help to produce the elements necessary for the skate;
• Extended planks for large homes. In this case, you need to make special holes for the bolts in the docking board. They must be drilled using a drill bit - only in this case the wood structure will not be damaged.

The developer must not forget about weight when installing a roofing system roofing material, and also about precipitation various kinds. As you know, in our country there is a snowy winter, during which it falls large number precipitation in the form of snow.

Wood shrinkage also plays a big role during the calculation of the roofing system. In this case, it is necessary to proceed from the dimensions of the log section. For example, with indicators such as 195x195 millimeters, the total shrinkage along the eaves or fronts should be 6%.

When everything important elements will be calculated and prepared, you can begin the construction of the rafter system.

The sliding rafter system consists of the following elements:

• roof ridge;
• rafter leg supports intended for intermediate beams;
• rafter leg supports intended for eaves overhang.

To attach the roof ridge, you need to purchase docking plates. As for the support of the rafter legs to the intermediate beams, in this case a rafter slide is needed. Such sliding elements are often used in the construction of rafters.

Sliding supports for rafters must be attached to each rafter in a perpendicular position (more details: " "). Slides for rafters must be made with precise cuts in the beams. Correct installation there will be rafters only if the element is installed at an angle of 90 degrees.

The slider can be installed in the most extreme position. In this case, maximum progress of the rafter system will be ensured in the further process of shrinkage of the house. That is, wood shrinkage will not affect the condition of the rafter system in any way. When the process has stabilized, the permanent roof covering can be laid again. Pay attention to the photo - they show the main elements of the sliding rafter system. The sliding support for the rafters is also shown here.

How to use sliding rafters

The device of sliding rafters is perfect for houses made of beams and logs. The photo shows some options for such buildings. As you know, houses of this type are settled at first, so roofing system must be properly thought out. Sliding rafter fastenings are especially important in this regard. In this case, the rafter legs are attached to the frame. This is typical for a log gable.

As is known, the shrinkage of log houses, amounting to almost 10%, occurs unevenly. This factor affects the condition of the entire building structure.

Usually sliding ones are attached to the rafters made of wood on the ridge log. In this case, the rafters can be connected end-to-end or overlapped. For this purpose, steel plates, bolts and nails are used.

The choice of rafter section will depend on the weight of the roof. Perfect fit edged board 50 millimeters thick and 200 millimeters wide.

The rafter legs cannot be attached rigidly to the mauerlat, since in this case the walls of the log house may burst, as well as the roof sagging. Sliding fastening of rafters involves the use of special brackets. They are usually made of two millimeter high-strength steel. They are also equipped with a corner that allows the support to slide. Such brackets can be purchased at any hardware store for an inexpensive price. The guide line of such a mechanism must be attached strictly parallel to the rafters. The corner on the log should be located in a perpendicular position.

Only in this case, during the shrinkage of the house, there will be no distortion. The corner should be attached at the level of the ruler at which further sliding of the rafters along the entire length is permissible when the process of shrinkage of the house occurs.

How the rafters are attached

The rafter must be correctly and securely attached. If it is simply rested against the beam, then with some force in the future the end of the rafter may begin to slide a little. This factor will ultimately lead to the destruction of the entire roofing system.

Thus, the rafters must be securely and correctly fastened. In this case, elements such as a tooth with a tenon and a stop, a tooth with just a stop, and a stop at the end of the beam are used.

The angle of inclination of the rafter will determine how many teeth the connection will take. It is usually done using one or more teeth. Using this method, the pressure of one element is transferred to another element.

If the roof slope is large, then it is better to use single teeth to connect the beams and rafters. Usually the angle of inclination in this case is more than 35 degrees.

• It is necessary to make a tooth with a spike in the heel of the rafter leg;
• You need to cut a certain stop in the beam. It must have a socket for placing a spike. The depth of the tenon in this case is approximately 1/3 of the thickness of the beam. Too much depth can weaken it;
• At a distance of 25 - 40 centimeters from the edge of the hanging beam, cutting occurs. In this way, you can avoid chipping its end under the load that may be caused by the rafter in the future.

As for single teeth, they usually have spikes, which in the future eliminate the possibility of the rafter leg shifting. This connection method is called a tooth with a tenon and a stop.

If the roof slope is, on the contrary, less than 35 degrees, then in this case the friction area on the floor beam must be increased. Thus, it is necessary to cut with two teeth.

It may have the following options:

• two stops, that is, to go with a spike or without a spike;
• have two stops with spikes;
• have a lock with 2 spikes.

There are other options with two teeth. The first method is the most common. In this case, a tenon with a stop for one tooth is cut into the beam, then it is cut out for the second tooth. Then an eye with a stop for the 1st tooth is made in the rafters, a stop is cut out for the 2nd rafter. The teeth should cut to the same depth at this moment.

Rafters can be connected by tightening, but this method is less common. In this case, a stop tooth is cut out in the rafter leg. One tooth plane is then placed on the edge of the beam surface. The second plane of the tooth should rest against the cut, which was specially made in the beam. The depth can be 1/3 of the beam thickness.

The basics of constructing a rafter system for wooden house, details in the video:

You can make the structure of the rafter system strong and reliable using bolts and clamps. Loops made of wires or iron strips will help attach the entire corner to the wall of the house. In this case, there should be anchor bolt, or a crutch embedded in the wall.

The rafters are connected using the following elements:

• dowels, plates, bars, insert or overhead triangular scarves - wooden roofing elements;
• bolts with washers, nuts, nails, screws, hinges, clamps, linings, etc. – metal roofing elements.

The rafter system must be properly attached. Only then will its design be reliable and last for many years. The installation of sliding rafters must be approached with special responsibility, since they are made on wooden houses, which shrink in the first two years.

One of important stages The construction of the roof is a sliding rafter system. It is necessary to take the fastening of elements seriously. That is why it is necessary to know how sliding rafters are attached and what they are needed for.

It is important to understand that the slightest inaccuracy or omission can lead to damage and destruction of the roof.

Therefore, the sliding support must be made as efficiently as possible.

Preparation of the necessary elements of the rafter system

Before starting the construction of the rafter system, it is necessary to prepare its individual elements:

1. The ridge is the topmost element of the roof structure. In order to make it correctly, after installing the very first element, it is necessary to make a template based on it, based on which the subsequent elements of the ridge will be manufactured;
2. If construction is planned big house, the boards may need to be lengthened. To do this, you need to make holes for the bolts in the docking board. The distance between the end of the joining boards and the nearest holes was at least 10 centimeters. Holes must be drilled using a drill to avoid damaging the wood. It is worth considering the fact that due to too frequent drilling, cracking of the board may occur. Therefore, it is necessary to drill in a random order.

What you need to know when calculating the rafter system

When calculating the system, it is necessary to prepare in advance for possible loads on the roof that may occur in the future: the weight of the roofing, as well as wind or snow loads.

Do not forget about wood shrinkage: with a log cross-section of 195×195 mm, the shrinkage along the eaves and gables can be about 6%.

Installation of rafter system elements

After all the calculations have been made and the elements have been prepared, it’s time to start.

Elements that make up the system

• supports the rafter legs on the eaves overhang;
• support the legs of the rafters on the intermediate beams.

Each element is fastened separately.

Fastening elements of the sliding rafter system

In order to secure the roof ridge, it is necessary to use special joining plates. Using them will not pose any difficulties, everything is simple here.

To support the rafters to the intermediate beams, you need to use special sliding elements.

The sliding rafter support must be mounted perpendicular to the rafters themselves. To do this, you need to provide an angle of 90 degrees, which can be achieved by making a precise cut in the bars above the main part of the sliding elements. This will help you install correctly.

The rafter system provides for the installation of a sliding element in the most extreme position, which is capable of ensuring maximum movement of the rafters during the process of shrinkage of the building.

Under such circumstances, wood shrinkage will not have any effect on the rafter system, and after the process has stabilized, it will be possible to begin laying a permanent roofing covering that can last for many years.

The sliding rafter system is most often used in the construction of houses made of logs or timber, in which noticeable shrinkage occurs from the very beginning. It is worth noting that the technology for fastening the rafter legs to the frame is especially important for a log gable.

The overall shrinkage of the height of a house can sometimes reach up to 10%. Since the shrinkage of such rooms occurs unevenly, it affects the dimensions of the structure.

In order to determine, you need to proceed from the weight of the roof that is being built. In most cases, an edged board is used, which is no more than 200 mm wide and its thickness is 50 mm.

How to avoid negative consequences during installation

Wooden houses shrink during the first years of operation, after which their geometric shapes and sizes gradually change under the influence of changes in humidity and temperature.

To avoid sagging of the roof or expansion of the walls of the log house, it is not at all recommended to rigidly fasten the legs of the rafters to the mauerlat. It is necessary to attach the rafter legs to the frame using special brackets, which are made of 2 mm steel and equipped with an angle, thanks to which the support can slide. You can purchase them in specialized construction stores, their price is quite low.

The guide ruler requires fastening parallel to the rafters. The corner on the log should lie perpendicular. This technology will prevent the rafters from skewing during shrinkage of the building. It is necessary to fix the corner at the level of the ruler, which can allow the rafters to slide along its entire length while shrinkage occurs.

If any force is applied to the rafter, which is resting against the beam, its end will slide along it, which may result in the rafter slipping and the destruction of the entire roof.

What needs to be done to avoid such slipping?

To avoid negative consequences, you need to securely fasten the rafters using special connections. Possible options:

• stop at the end of the beam;
• tooth with emphasis;
• tooth with a spike and stop.

Connections must be made with one or more teeth. The quantity depends on which one. This fastening of the rafters to the beams will reduce the pressure by transferring it from one to the other.

One-tooth connection method

If the angle of inclination of the roof is large enough, it is best to make beams using a single tooth. It makes sense to use this mount if the angle between the rafter and the beam exceeds 35 degrees. Actions required:

1. IN rafter leg you need to make a tooth with a spike.
2. In the beam itself, you will need to cut out a stop in which there will be a socket for the tenon, the depth of which should be 1/3 - 1/4 of the total thickness of the beam. If the nest is deep enough, it may weaken.
3. The cutting must be carried out at a distance of 30-40 cm from the edge of the hanging beam, and it is necessary to prevent its end from chipping under the load that will be created by the rafters.

A tooth with a tenon is made in the heel of the rafter, and a stop with a socket for the tenon is cut out in the beam.

The tenon and stop tooth is a single tooth that can be combined with tenons. They will help prevent lateral movement of the rafter leg.

If the roof is flatter, that is, its angle of inclination is less than 35 degrees, it will be necessary to increase the area of ​​support of the rafter leg on the beam.

Options for cutting with two teeth

To do this, you need to cut with two teeth. There are several options here:

• two stops: with and without a spike;
• a lock with several spikes;
• two stops with spikes.

The first option is carried out in the following steps:

• a stop is cut for one tooth;
• for the other, a tenon with a stop is cut out in the beam;
• For the second tooth, an eye with a stop is cut out in the rafters.
• a stop for the first tooth is cut out.

It is worth considering that the teeth must be cut to the same depth. With different cutting depths, it will be necessary to cut the first tooth with a tenon at 1/3 of the total thickness of the beam, and the second tooth at 1/2.

Another method of fastening, which is less common, is the end-to-end connection. To do this you need:

• cut out a persistent tooth in the rafter leg;
• place one tooth plane on the very edge of the beam plane;
• make the second plane of the tooth rest against the cut that was made in the beam (the depth of the cut should be 1/3 of the total thickness of the beam).

How to fasten the elements of the rafter system

Using a sliding rafter system means installing timber rafters onto the roof ridge logs. The connection is made overlapping or butt using nails or bolts and steel plates.

In order to make connections to the rafter system, the following fasteners are used:

• everything made of wood is fastened using plates, dowels, bars, overhead or insert triangular gussets;

basis pitched roof is the rafter system, which is responsible for the reliability of the entire structure and determines its appearance.

In the construction of a roof, one of the most critical moments is the fastening of the rafters.

Purpose of the sliding rafter system

During construction wooden houses it is very important to take into account one feature - over time, the tree shrinks, and this process occurs with varying intensity in various parts roofs: the greatest shrinkage, as a rule, is observed under the ridge, the smallest - at the side walls.

Thus, the triangle of the log gable changes and the entire geometry of the upper structure of the building is disrupted.

The way out of this situation is to use moving elements as fasteners instead of the classic rigid fastening of rafters with staples or screws.

The rafter legs are connected to the mauerlat - the upper crown of the frame - using sliding supports. Thanks to the “sliding”, the rafter beam can move a certain distance along its axis.

This method compensates for deformation due to shrinkage, and at the same time ensures sufficient strength of the structure.

If the rafter beam is able to move slightly without compromising the integrity of the slopes, this will evenly distribute the load and avoid skewing the roof.

In addition, the use of a movable connection simplifies installation work– sliding fastenings reduce the complexity of the roof construction process.

Features of sliding rafter fastening

Pairs of rafter legs must be made according to a single pattern, of the same size. At the ridge of the log house, the rafters are connected using special plates.

There are two connection methods:

• overlap;
• end-to-end In this case, be sure to leave a gap.

The lower end of the rafter leg is fixed with a sliding fastener.

The rafter legs are laid:

• above;
• with an insert into the body of the Mauerlat.

Structurally fastener consists of two parts: a metal strip is fixed to the rafter leg, a corner with a loop is fixed to the supporting beam. Both parts are made of durable galvanized steel.

The fastenings are:

• single;
• double.

Screws must be used with an anti-corrosion coating to prevent damage to the wood at the joints.

Sliding bearings can have different stroke lengths, from 60 to 160 mm - it all depends on the what is the expected displacement of the rafters in relation to the mauerlat.

In case self-made“slider” you need to use a template, making all the details the same.

To prevent the end of the rafter from sliding along the beam, it is fixed using special methods.

Fixation methods:

• one tooth with a stop. This method is used to make a connection in case of a large slope - if the angle between the rafters and the beam is 35 degrees or more;
• tooth with a spike and stop. To avoid sideways movement of the rafter leg, a tenon is used along with a single tooth;
• with a stop at the end of the beam. This method involves cutting out a stop tooth, one plane of which rests against the groove of the beam, the other rests on the end of the beam.

The two-tooth notch is used for less steep roofs when the angle is less than 35 degrees. There are also several design options: one stop with a spike and one without, both stops with spikes, as well as the use of a lock with two spikes.

• each rafter is made of boards, usually 150 or 200 by 50 mm. If there is a need to lengthen the rafter leg, the extension is made with an overlap, placing the holes randomly - this will prevent the wooden board from splitting;
• the supporting log in the center should be perpendicular to the sliding elements;
• all sliding elements are fixed on semicircular cuts parallel to each other to prevent jamming. In this case, it is necessary to select the extreme position of the “slider”;
• in the ridge connection of the sliding rafter system, hinged connections must be used;
• supports are installed on both sides of the rafters, with the exception of small ones roofing structures, for which no serious wind load is expected.

It must be remembered that the installation of a sliding rafter system is justified only for a gable symmetrical roof.

Allowed to use this method and for pitched roof, since from an engineering point of view, a gable roof is a pair of lean-to roofs.

A simple method has proven to be effective: using sliding rafters allows you to balance the roof wooden log house and prevent its deformation during the most difficult first time after installation, when wood shrinkage can be up to 15 percent per year.

A sliding support for rafters is a necessary part of the frame of any roof with inclined slopes.

Sliding supports or slides are a kind of fastener that allows the rafters to slide along the crossbar on which they are attached.

This is necessary so that during the shrinkage of the house the rafters do not get torn out “with meat”.

Scope of application

Over time, the building shrinks. This process is uneven - some walls shrink faster, others slower.

This leads to a change in the angle of inclination of the slopes. These changes must be taken into account at the stage of installing the roof. Sliding supports allow the rafters to be movably secured.

Sliding holders attached to the skates allow the rafters to rotate relative to the crossbar on which they are attached.

It is more difficult to create a movable connection at the heel of the rafters, since this part must be able not only to rotate, but also to move parallel to the wall.

If the rafters are fixed motionless on a building prone to shrinkage, then after some time these roofing elements will deform, which will lead to the destruction of the entire structure.

By providing the rafters with at least a slight rotation and the ability to move along the wall, you can get rid of this problem. It is important that the rafter holder does not lose its strength.

Previously, rafters were secured in a sliding manner with burnt wire, which was simply tied to the rafter leg to the crossbar.

The wire secured the rafter and at the same time allowed it to move a few centimeters.

Now, for the same purpose, sliding supports for rafters are used - industrially manufactured hardware.

Such fasteners are more convenient to install and stronger than wire. It is securely fixed to the Mauerlat or ridge.

If the parts of the rafter system are made of laminated veneer lumber, then the sliding supports become the only way secure the rafters firmly enough.

The holder is fixed to the area along the displacement of the crossbar. To do this, a small area is ground off on the timber. The stationary part of the holder is fixed to the resulting flat area.

Sliding supports are installed on both sides of the rafter legs, on more flat roofs It is permissible to use one fastening for each rafter.

In a layered system, sliding holders are fixed to the mauerlat, ridge and intermediate supports.

Sliding bearings can be divided into two types.

Open - such a holder consists of two parts: a guide and the mount itself.

The guide is fixedly fixed to the rafter - this part is a curved metal plate, at one end of which there are holes for threaded fasteners.

The guide includes a movable part of the sliding support, which is called the “angle”. He should be able to move along the guide at a distance of 6 to 16 centimeters.

The closed sliding support is installed in assembled form. There is a holder hole on the corner - a bar is inserted into it and both ends are fixed to the rafters motionless. In this case, the rafters will be able to move both left and right and up and down.

Manufacturing of sliding supports

Roofing fasteners operated in unfavorable conditions. In some cases it comes into contact with water. It may be exposed to condensation formed in the under-roof space.

Therefore, sliding supports are made of durable metal- alloy steel – and coated with an anti-corrosion zinc layer with the addition of alloying substances that increase the corrosion resistance of the coating.

Strong and reliable hardware increases the load-bearing capacity of the rafter system.

The sliding holders themselves are made by cold stamping from steel 08 PS. The low carbon content in the metal allows for high-quality stamping of products. To increase strength, the part is deoxidized.

If the fastener does not have electroplating, then before installation it must be coated with a layer of oil paint.

General rules for the operation and installation of sliding rafter systems:

• sliding rafter systems can be installed on a building of the correct geometric shape;
• there are moving parts in the system, so before the installation of the roof begins, the perimeter of the box is measured and checked for compliance with the project;
• the rafters themselves are made according to the same template - this allows you to get the same parts;
• in sliding rafter systems, the moving unit is usually made on the mauerlat, and sometimes also on the ridge ceiling;
• to create movable units, studs and screws are used as connecting axes;
• long spans are covered with built-up lumber, and the connection is overlapped using brackets or self-tapping screws;
• when building lumber, mounting holes are made in them in advance;
• distance from mounting holes to the edge of the board is at least 10 centimeters;
• to ensure the strength of the connection, the holes are drilled in a chaotic manner;
• each support of the sliding rafters is installed parallel to the previous one and at an angle of 90 degrees to load-bearing beam- this will provide protection against jamming of moving elements;
• sliding supports are fixed perpendicular to the rafter;
• the sliding support is attached with nails or self-tapping screws with an anti-corrosion coating;
• the length of the rafter stroke in the support must correspond to the calculated value of the displacement of the walls during shrinkage;
• insertion into the Mauerlat should not be made deeper than 1⁄4, so as not to weaken this the most important detail rafter system.

Typically, sliding bearings are produced following sizes(in centimeters):

• 9x9x4;
• 12x9x4;
• 16x9x4;
• 27x9x4.

Hinge rafter joint over ridge log

There are several ways to secure rafters to a ridge log:

• end-to-end;
• overlap;
• on a chase and/or ridge beam.

When fastening end-to-end, it is impossible to make a sliding fastening of the rafters. The upper ends of the rafters rest against each other and are fixedly fastened metal plates, which will not allow them to move.

When attaching the rafters to the purlin, they are not only fastened end-to-end over the ridge, but are also placed in the cut on the ridge beam and purlin, that is, the rigidity of the rafter fastening increases.

If the rafters are attached to the ridge beam using the end-to-end and purlin methods, then a sliding support is installed at the junction of the rafters with the mauerlat.

You can do this in one of the following ways:

• make a cut on the rafters and lay them on the mauerlat;
• connect the elements obliquely with two nails;
• secure with one nail, driving it from top to bottom into the Mauerlat through the leg;
• use steel plates with holes instead of nails;
• secure the leg to the Mauerlat using a bracket;
• release the rafter leg beyond the wall and secure it with a fastening plate;
• use special fasteners - slides.

All these fastening methods will allow the rafter to rest on the base beam, but when moving the frame elements, the parts of the rafter system will be able to move, which will prevent subsidence and deformation of the roof or the upper part of the walls.

For a movable connection, the overlap method is suitable. In this case, you can use a hinged connection rather than sliding supports.

The rafters above the ridge beam are connected not by their ends, but by their sides and are fastened to each other with a bolt or pin, which allows them to move relative to each other in the vertical plane.

Step-by-step algorithm for installing sliding elements on the Mauerlat:

1. in the upper part of the mauerlat, cuts are made with a depth of approximately one quarter of the height of the beam;
2. a rafter leg is inserted into the cut - it must fit firmly into the gap prepared for it;
3. on the right and left of the rafter leg are secured by sliding supports open type, one on each side;
4. First, the guides are secured by screwing galvanized screws into the holes located at the ends of the part.

Important: the guides are not screwed to the top or side plane of the Mauerlat, but to its edge. To do this, the edge is first cut off so that in place right angle it turned out to be a flat platform.

The sliding support is secured on the other side of the leg in the same way. That's it, the movable rafter assembly is ready.

When working with a power tool, it takes no more than three minutes to secure one sliding support, and ten minutes to install the entire moving unit, including working with an electric saw.

What happens if the rafters are fixed motionless in a building subject to shrinkage? The consequences for the building will be the most dire. The shape of the deformation will depend on the type of roof.

For example, when gable roof after the façade shrinks together with the pediment, a through gap is formed between the wall and the roof, into which a hand can freely pass.

But it’s even worse if the side walls settle - in this case, the slopes will acquire a concave position and the entire roof will have to be redone again to return it to its normal appearance.

Sliding rafters allow the roof frame to sag simultaneously with the shrinkage of the gables, which helps keep the walls intact.

Sliding fasteners designed for rafters can be used not only in roofing work, and wherever movable connections are required: during construction wooden partitions, finishing the walls of wooden houses with tiles, etc.

A house made of solid or laminated wood inevitably settles. This is the result shrinkage wall material(shrinkage), which is most pronounced in the first few years after the construction of the building. But even then the linear dimensions of the wood will fluctuate, due to seasonal changes in temperature and humidity conditions. That is why, even at the design stage of a wooden house, it is necessary to provide special measures to compensate for wall shrinkage, especially when it comes to building a house from logs or timber.

Shrinkage of houses made of logs and timber

House shrinkage is mainly due to the property of wood to dry out when its moisture content decreases. The amount of shrinkage of a log house is determined by many factors. First of all, the moisture content of a log or timber, its original dimensions (primarily thickness), wood type, wood processing technology (primarily drying), operating conditions of the building and its dimensions (the higher the wall, the greater the shrinkage value), construction season at home (summer, winter), quality of assembly and qualifications of workers (quality and tightness of fit), construction technology (method of connection and type of used).

Moreover, size changes wooden element are different in the tangential and radial directions, i.e. the changes in dimensions along the width of the beam or log are much greater than along the length. In addition, the amount of shrinkage varies depending on the type building material- log, rounded log, beam, profiled beam, laminated veneer lumber, etc.

In principle, data on material shrinkage can be gleaned from, but in practice these data may be far from theory. On average, with calculation of shrinkage amount You can start from the following data:

• The log shrinks up to 150 mm;
• A rounded log shrinks up to 100 mm;
• Planed or unplaned timber can shrink up to 60 mm;
• Profiled timber natural humidity shrinks up to 40 mm;
• Profiled timber chamber drying will shrink up to 20 mm;
• Glued laminated timber is least susceptible to shrinkage, the amount of shrinkage is no more than 15 mm.

For example, in the assembly manual log houses HONKA provides the following data:

• a wall made of rounded logs shrinks on average 30-60 mm/m,
• wall made of laminated veneer lumber - about 10-30 mm/m.

The difference is noticeable, and in many cases fundamental, because the height of the log house will in any case decrease. To prevent shrinkage from damaging the structure of the building, a number of measures and ways to compensate for it are provided. Let's start with the fact that the very shape of the beam or log profile affects the amount of shrinkage of the walls.

The profile of a rounded log can be supplemented with narrow longitudinal compensation grooves

For example, the profile of rounded logs can be supplemented with narrow longitudinal compensation grooves, reducing stress in the wood and avoiding severe cracking of the log. The number of grooves is from one to three, and one of them is located, as a rule, in the upper part of the log. Thanks to the grooves, the change in profile shape is reduced and, consequently, the shrinkage of log walls is reduced. The higher the level of technical solutions of the manufacturer of wooden building materials, the more complex profile the wall elements he offers.

Shrinkage of walls and partitions in a wooden house

The log walls themselves do not require special units to compensate for shrinkage, since the log house is a homogeneous structure and all its elements will sink by approximately the same amount. However, there are rigid parts in the building that either do not settle or settle much less than the frame. Therefore, the construction of such parts requires special solutions.

Thus, the house often has vertical elements (pillars, columns, etc.) that serve as support for the higher parts of the house. Adjustment mechanisms are needed to reduce the height of pillars and columns so that their height matches the height of the log house walls. Most often for this use screw mechanisms for shrinkage compensators, special jacks, which are called so - screw jack adjustable shrinkage compensator.

Wooden posts are rigid elements. To prevent them from interfering with the shrinkage of the overlying log structures, adjustment mechanisms are provided to allow the height of the pillars to be reduced.

The jack is placed in the gap between the vertical and horizontal elements, rigidly fixed to one of them. The size of the gap is selected based on the estimated shrinkage of the building (usually a jack allows you to change the height of the support by 8-10 cm). As the log house shrinks, the screw mechanism is adjusted, thereby changing the height of the column or pillar. The jack can be installed at the bottom or top of the vertical support. From the point of view of shrinkage of the structure, its location is not important. And from the point of view of ease of use, it is preferable to have a jack located below - then you will not need a ladder or scaffolding to complete the work.

The adjustment mechanisms are screw jacks, which are installed in the gap between the vertical and horizontal elements, rigidly fastening to one of them.

The gap between the vertical and horizontal elements is usually covered with a decorative casing, which is removed during adjustment. Sometimes the screw mechanism is left open. How often do you have to reduce the gap? This depends on the type of wall material, profile shape, time of year (seasonal changes in wood moisture content) and log house assembly technology. In some companies the interval between jobs is usually from two weeks to three months, in others it is four to six months. Adjusting each jack takes approximately 15 minutes.

Special technical solutions will also be needed when the log structure is adjacent to a wall or partition of another type (for example, brick or frame), which is subject to less shrinkage. This means that its connection with the log house must be sliding. This connection can be made in different ways. Most often it is carried out according to the “tenon and groove” principle, where the tenon and groove have the possibility of some movement in the vertical direction relative to each other. Usually a groove is made in the wall of a log house, and a tenon in the form wooden block attached to the end of a brick or frame wall. The space between the tenon and groove is filled with heat-insulating fibrous material (etc.). Connection with brick walls, through which capillary moisture can spread, must contain a layer of waterproofing.

Connection of a frame partition with a log wall: 1. Log house 2. Frame partition 3. Groove

Connection of a brick partition to the log structure located above: 1. Log house 2. Brick partition 3. Decorative strip 4. Shrinkage allowance 5. Screw jack

A gap is left between the upper edge of the brick or frame wall and the part of the frame located above for unhindered shrinkage of the latter. The size of the gap is determined based on the calculated shrinkage value (in most cases it is 8 - 12 cm).

Creation of an additional self-supporting brick partition on which the finishing material will be fixed

To prevent the gap from being noticeable in the interior, you can close it with decorative strips attached to the frame (and, therefore, descend with it), or you can create a niche in the partition where the frame will settle. At the junction of the upper part of the frame partition to the frame, steel rod elements are usually provided to ensure the rigidity of the structure.

Shrinkage compensation for rafter systems

When creating a rafter system, the shrinkage of the log house is also taken into account. So, in the case of using layered rafter legs, the distance between the upper and lower supports may vary. Accordingly, the rafters must be able to move without causing stress and deformation in the building structure.

Layered rafter systems are used in houses where there is a middle load-bearing wall or columnar intermediate supports. The ends of the rafter legs rest on the outer walls of the house, and the middle part rests on interior wall or supports.

To do this, the lower end of the leg is secured to the wall using a sliding joint of one type or another. Most often, fasteners are used in the form of two brackets: one is rigidly fixed to the wall, the other to the rafter. These brackets allow the rafter to move relative to the wall.

There is no consensus among experts whether a sliding connection is necessary at the point where the upper end of the rafter leg rests on the ridge beam. Some insist that this is a mandatory measure that helps prevent deformation of the rafter system due to shrinkage of the log house. This measure consists in leaving some distance between the rafters converging at the ridge and attaching them to the ridge beam also by means of a sliding (usually hinged) connection. Other experts believe that to compensate for the shrinkage of the frame, sliding fasteners in the place where the rafter rests on the wall are sufficient.

Fastening the rafter leg to the log wall: 1. Rafter leg 2. Brackets that allow the rafter to be displaced relative to the wall 3. Log house

In the case of rafters in the form of trusses, the shrinkage of the frame does not lead to a change in the slopes of the roof slopes. However, it is impossible to rigidly connect gables made of logs or timber with trusses, since the gable walls are higher than the facade walls, and the amount of their shrinkage will be different.

The truss structure must be designed taking into account the shrinkage of the building. Most often, layered rafter legs are used, which rest on one side on the top element of the frame, and on the other on the ridge beam or the wall of the house (when the roof slope is adjacent to the wall). On the ridge, at the point where the rafters of adjacent slopes meet (or at the point where the rafters adjoin the wall), a distance of about 3 cm should be left so that when the roof shrinks, the rafter legs can lower without hindrance.

The fastening of the upper part of the leg itself is carried out using a metal hinge joint of one type or another, which allows you to change the slope of the rafters when the log house shrinks. Sliding fastening is also necessary in the node where bottom part legs rest on the wall of the log house. Here, as a rule, a factory-made sliding support is used, thereby allowing the rafter leg to “move” relative to the wall.

Shrinkage compensation for windows and doors

Among the structures in a log house that do not change their size are windows and doors. A special system for filling the opening allows you to prevent their deformation due to shrinkage of wood. The window or door frame is not attached to the frame, but to a special casing (frame, casing).

The connection between the box and the walls of the building must be sliding. The design of this unit varies. As a rule, a groove is cut out at the ends of log elements. Mounting bars are inserted into the grooves, securing them at the bottom of the opening. The casing is attached to the bars. The gap between it and the end surfaces of the log house is filled with fibrous insulation (linen, jute, etc.) to prevent freezing in the opening area. Between top part boxes and a frame element covering the opening leave a gap allowing the frame to lower. Its size is determined by the amount of probable shrinkage of the wall and most often is 5-7 cm.

Installation door frame to the casing in wooden house

To install a window casing, first insert a mounting block into the groove made in the end of the log wall. Then the box itself is attached to the block. Place between it and the wall thermal insulation material

To avoid heat loss, heat-insulating material is placed in the gap - linen, jute, etc., strips mineral wool, polyurethane foam tapes, etc. It is recommended not to use polyurethane foam for these purposes, which is usually used to seal the window or door frame itself, since it is quite rigid and can deform the structure of the window or door when the frame shrinks. To decorate the gaps at the junction of the filling elements with the frame, external and internal platbands are used.

A compensation gap is left between the casing and the log house element located above it (on top).

When installing window fillers and doorways In houses made of solid and laminated timber, two types of risks are likely. Firstly, the impact of the log wall on the infill elements due to the settlement of the building. This risk is eliminated by creating sliding connections with the parts of the log house that form the opening, by organizing a gap above the infill structure, and by attaching the platbands to the infill elements and not to the walls of the log house.

The second group of risks is insufficient tightness of joints in places of sliding joints. Application polyurethane foam for filling the gaps between the casing and the log house is unacceptable, since the hardened foam will prevent shrinkage, because of this, either the log house will “hang” above the structure of filling the opening, or it will be deformed and damaged. The best solution- the use of thermal insulation of plant origin in the gaps in combination with film protection - a layer of vapor barrier from the inside of the house and a vapor-permeable wind barrier from the outside.

Compensation for shrinkage during the construction of stairs

When designing and installing a staircase in a wooden house, it is necessary to take a number of measures to prevent it from being affected by the building’s settlement. The staircase is installed at the final stage of construction, when some shrinkage has already occurred. The base of the staircase (stringer or bowstring) is attached to the upper ceiling using sliding fasteners ( metal corner with a vertical groove, etc.), intermediate fixation to the walls is unacceptable.

Installation internal stairs: 1. Screw with washer 2. Angle with vertical groove 3. Floor joist 4. Shrinkage reserve

The shrinkage of the frame should be taken into account when securing the fencing and stair railings.

If the flight of stairs has a platform, then it also cannot be attached to the walls - it should be supported by the racks on the lower floor, and then the shrinkage of the walls will not affect the structure. Moreover, during construction work there is no need to bring the upper part of the stairs adjacent to the ceiling into the plane of the floor of the upper floor. It is necessary to leave a gap equal to the calculated shrinkage between the top of the stairs and the floor, which is leveled during the settlement of the floor.

Finishing a wooden house taking into account shrinkage

Owners of wooden houses often want to decorate some rooms (for example, tiling a bathroom). To prevent damage to the finishing layer when the log house shrinks, it is fixed to a base, either connected to the log walls with sliding fasteners, or completely independent of the walls. There are many options for sliding fasteners.

Construction of the base for finishing: 1. Log house 2. Frame made of wooden blocks 3. Angle with a vertical groove and a screw with a washer 4. Gypsum fiber or plasterboard boards

One of them involves a frame made of metal profiles or wooden bars with longitudinal grooves. The frame is attached to the wall with screws through the grooves, and the screws are not tightened tightly so that they can move vertically as the wall shrinks. The finishing base is rigidly fixed to the frame. A gap is formed between the wall of the room and the base equal to the thickness of the frame (usually it is about 5 cm).

If you provide ventilation in the gap (provide the possibility of air flow at the bottom of the structure, and ventilation at the top), this will increase the durability of the wall and base. A compensation gap is left between the top edge of the trim and the ceiling, which is decorated (for example, covered with a suspended ceiling). An undoubted advantage of the base on the frame is the relatively small load on the floor covering. Disadvantage - there is some risk of deformation of the frame when fastening it to the wall too rigidly or when uneven shrinkage adjacent log walls of the room. Misalignment can damage the finish. This drawback is more often manifested in houses made of chopped and rounded logs of natural moisture than in houses made of laminated veneer lumber.

The frame is in the form of wooden blocks, fixed to the log wall with sliding fasteners. The base for finishing will be fixed on the frame

For rooms located on the first floors of a building with a foundation in the form reinforced concrete slab, there is another solution. The finishing layer can be mounted to additional self-supporting partitions made of ceramic bricks half a brick thick or tongue-and-groove gypsum board(a similar design is often called a “glass”). These partitions are erected at a distance of at least 2.5 cm from wooden walls, making holes at the bottom and top for air supply and exhaust. If the room is made suspended ceiling, then it is attached only to the upper ceiling so that they fall together.