Ukosina is a durable board installed in the walls of frame buildings. Structurally, such a beam provides additional strength and prevents changes in the geometry of timber frame houses. Unlike the main struts located vertically, the jibs are built into the structure at an angle, which gives it the rigidity necessary to withstand lateral loads, for example, when exposed to wind, snow, etc.
The need to use
The internal "skeleton" of a frame house is equipped with vertical struts installed with a certain pitch, which connect the upper and lower strapping of the structure. The durability and reliability of the structure largely depends on the reliability of the resulting frame. However, this design ensures the stability of the house only with a vertical load. When exposed to lateral forces, the frame is capable of losing stability.
To give the structure resistance under the influence of loads of different directions, boards are stuffed diagonally (jibs) on top of the vertical posts. Their purpose is to give the frame additional spatial rigidity, while making it more reliable and stable. Without such elements, the frame can change its geometry over time, which will contribute to the destruction of the interior and exterior decoration of the house, loss of heat and, ultimately, the complete destruction of the house.
The use of jibs in the construction of a frame house allows:
- Improve the spatial rigidity of walls and the structure as a whole.
- Prevent wall displacement.
- To increase the ability of a wooden building to withstand natural disasters (earthquakes, ground movements, hurricanes, etc.).
Jibs are not used in the construction of small buildings: utility blocks, toilets, etc. You can also do without them if an oblique lathing was used when arranging the external surfaces of the structure.
Installation methods
When installing the frame of a wooden house, the jibs are driven into the load-bearing walls (external and internal) between the racks:
- diagonally;
- parallel to each other;
- crosswise.
Moreover, their lower part should be as close to the center of the wall as possible, and the upper one - to the upper corner.
Small jibs are allowed not to be driven in between the racks, but to be nailed to them. Since the boards are installed diagonally, their length can exceed the length of the frame posts by about 30%.
The recommended angle at which the jibs are installed is 45 ° relative to the floor plane. In cases where this is not possible, for example, in the presence of window or door openings, boards can be driven in at an angle of about 60 °.
If necessary, several jibs can be installed in one wall. At the same time, two jibs are installed on the outer walls, located along the edges, where the outer corners are located. One of them is mounted with a slope to the left, and the second is driven in on the opposite side of the same wall with a slope to the right. In addition, these stiffeners must be reliably connected to the harness and frame posts. All this ultimately makes it possible to stabilize the position of the frame as a whole.
Varieties of jibs
In construction, two types of jibs are used - wooden and metal.
Wooden jibs are made from boards 25x100 mm in size. They are quite durable and do their job quite well. However, they do not significantly affect the weight of the entire frame.
Metal jibs are heavy and can withstand strong stress, successfully coping with heavy loads. They are mounted crosswise, having previously well insulated from moisture. Otherwise, the metal will begin to rust, which over time will lead to its complete destruction.
Jibs are temporary and permanent. The permanent ones are designed to strengthen the frame throughout the entire life of the building, and the temporary ones are used to tie the intermediate and corner posts until the upper harness is fastened. They are also used to level the walls of the frame, which will help to avoid problems in the interior decoration of the walls in the future.
Do not confuse jibs with struts. The latter really give additional rigidity to individual structural elements, for example, cells of quadrangular blocks. At the same time, they have no effect on the rigidity of the frame as a whole.
Installation features
Jibs are made from well-dried coniferous boards. Indeed, when wet boards dry, gaps will appear between them and the frame elements, reducing the rigidity of the structure as a whole.
When installing permanent jibs in a frame house with your own hands, it is necessary to take into account that they must form a right-angled triangle with a corner post. It is equally important to place them flush with the plane of the latter. This can be achieved if grooves are cut in the frame racks, where these boards will then be inserted. The same grooves are cut in the upper and lower strapping.
With the strapping of the ceiling and floor, additional stiffeners are connected with powerful bolts, and they are nailed to the racks.
Self-tapping screws cannot be used to fasten the jibs.
With the correct installation of the jibs in the frame house, all elements that ensure the rigidity of the structure will fit snugly to the frame and will not interfere with the arrangement of the cladding.
Temporary stiffeners are cut into the racks and there is no need to harness. After the upper frame strapping is fully completed, the temporary jibs are dismantled and further used for other purposes.
Installation errors
When installing jibs with their own hands, homeowners who do not have sufficient experience often make the same mistakes:
- insufficiently rigid fastening of the jibs to the frame elements;
- use of low-quality wood or defective boards for the manufacture of stiffeners;
- incorrect slope of the jibs relative to the floor;
- the use of scraps of boards, which are stuffed chaotically, as jibs;
- insufficient length of the boards.
Another fairly common mistake is the refusal to use jibs in general in the hope that the frame sheathing with chipboard or OSB will give the necessary rigidity to the structure. However, such sheathing will only add rigidity to the connection within the frame cell, and not to the entire frame as a whole. After all, the frame structure is a hinge joint and does not imply the presence of additional stiffeners that can withstand lateral loads.
