In low-rise private housing construction, staircases of different models, sizes and shapes are used. One of the most popular, as practice shows, are metal stairs on the kosoura. These designs are reliable, relatively easy to manufacture, practical and, from the point of view of aesthetics, stand out from the rest of the species. Before you start assembling the structure with your own hands, we will deal with different types of kosour.
Varieties and design features of Kosoures
Kosour is a beam, which at its ends abuts against floor floors, connecting the upper and lower levels of the building. In fact, this is a supporting element of the staircase on which the steps lie and all parts of the lifting system are attached.
There are several varieties of slanting stairs, which differ from each other in the number of beams.
- Single These are structures, which include one kosour located in the middle of the span.
- Double. These are two support beams on which steps are installed from above. A common option, especially when stairs are made of wood. By the way, the construction on the strings is very similar to them. Only here the steps are located between the beams in special grooves.
The skewers themselves can be located relative to the steps strictly along the edges or with a slight displacement inward.
- Triple. This is when three load-bearing beams are installed: two at the edges, one in the middle. It makes sense to assemble such a design only if the length of the steps exceeds 2 m.
And a few more terms that are used by specialists in the process of manufacturing stairs on Kosoura:
- fillies are small devices with which support for steps is formed.
- the comb is the kosour itself, which in shape is a stepped structure from separate parts of the bearing profile.
As for the material from which the stairs on the kosoura are assembled, then most often a steel pipe or channel is used. It is important to understand here that both profiles must have increased bearing capacity, especially for models with one slant. The staircase itself is assembled with the help of electric welding, so for independent work it is necessary to master this skill.
Scheme with two braids
The double construction is determined by the presence of two Kosoures in it. The simplest option is when the ends of the profile metal are fixed between two floors without turning. That is, in this case, it is a rectilinear design.
The main requirement for the proper installation of kosour is the same length of the beams and the exact distance between them along the entire longitudinal arrangement. In this case, the fastening of two parallel-laid elements is made to the supporting elements of the upper and lower floors.
It is more difficult with a rotary system when the structure is separated by an intermediate platform, and the upper part is rotated at some angle relative to the lower one. More often than not less than 90 °. In this case, the issue of safety and strength of the object is solved by additional fastening of the kosour either to the walls or to the supporting posts, which are installed under the platform and the upper part of the span. However, if you correctly calculate the elements of the system for loads, the metal profile can withstand quite a serious weight without additional fasteners. This strength is the main difference between metal stairs and wooden.
The most complex node in the entire rotary structure is the transition through the site. Here it is necessary to observe the absolute accuracy of the parameters of the staircase itself, which do not change when moving from the lower to the upper. However, metal stairs with one or two braids can be made without an intermediate platform - you can use the cross-country steps.
Single central skew pattern
This original and superficially simple design requires special attention in comparison with other lifting systems. One kosour takes over the entire weight of the march. In addition, the shape of the profile must take into account additionally arising torsion loads. Therefore, it is important to choose the right shape and cross-section of the kosour. In general, a pipe with a cross-section of 150x150 mm with a wall thickness of at least 6 mm is suitable.
The staircase on the kosoure from the channel is considered convenient for installation work. The profile is stable, there is no need to twist it, exposing it on floors. The channel is laid on a shelf, which has a sufficient width, providing rigidity and reliability of the installation. At the same time, the installation of steps, or rather filly, is also simple and convenient, which can not be said about the pipe.
A feature of single staircases on the kosoura is the airiness of the structure. In addition, there is an opportunity to save a little, because the number of elements is reduced. But do not think that the savings will be big, because the central kosour requires platforms under the steps to which separate supports are made (one or two). They can be of different shapes, usually rectangular or triangular with a slit.
The supports are installed at an angle to the kosour and form a horizontal plane for attaching the steps. The fastening to the beam itself is electric welding.
Tilt angles and steps
The optimal angle of inclination of the stairs in relation to the floor plane should be 20-45 °.
But since this is an ideal option, and in practice there are different situations that differ greatly from the optimal one, each case is examined individually. If the area of the room allows, it is better to make the angle smaller, which makes the structure more comfortable in terms of movement along it. If the premises are small, then the staircase is exposed at a large angle.
The latter situation is problematic and is solved by reinstalling the steps. Here there is an optimal option when one step hangs over another, but at the same time their projections do not coincide relative to each other. In a situation with a large angle, everything is different. The steps will hang over each other with an overlap in the projection. But we must not allow the displacement to be more than 8 cm. This is laid down by GOST and SNiPs on stairs.
How to accurately calculate kosour for stairs
First of all, it is necessary to determine the parameters of the structure itself. Some of them are permanent, others can vary.
- H - ceiling height;
- H1 is the height of the stairs;
- L is the length of the projection on the floor;
- h is the height of the approach;
- l is the depth of the step;
- n is the number of steps;
- L1 - the length of the opening on the top floor.
According to building standards, it is accepted that the value of "H1" should not be less than 2 m, "l" varies in the range of 25-30 cm, "h" - in the range of 12-25 cm.
Of all the indicated values, the parameter "H" is a constant value and is determined by the design of the building. All other dimensional indicators are adjusted to the dimensions of the space.
Calculation of the number of steps
Input data:
- H = 3 m;
- h = 18 cm.
The number of steps is N / h = 300: 18 = 16. But you need to understand that the last upper step is the floor of the upper floor, so 15 steps must be attached to the kosour.
Calcium length calculation
Knowing the number of steps, one can derive the length of the projection of the flight of stairs, for which the depth of the steps is determined. For example, it is 28 cm. Now the following mathematical calculation is carried out: 28x15 = 4.2 m. This is the value of the “L” indicator.
When there is a size of the height of the ceilings, there is the length of the projection of the stairs, it remains according to the Pythagorean theorem to determine the length of the kosour.
H² + L² = P², where P is the length of the stairs.
3² + 4,2² = 26,64 - this is R². So, P = 5.16 m. This is the length of the kosour necessary for the construction of a flight of stairs according to the given parameters.
Online calculator
For convenience, we have made a selection of online staircase calculators, with which you can independently calculate all design parameters, as well as the nomenclature and amount of material needed.
Instructions for installing stairs on Kosoura
The dimensions of the structure are known, you can begin to carry out installation work. Here are the main steps in this process.
- Channel, pipe or tee are cut according to the estimated length of the kosour.
- On it the places of installation of steps are evenly distributed taking into account the estimated number and parameters.
- Installation and fastening of the filly is carried out.
- Installation of kosour in place.
- Installation of steps.
Do-it-yourself installation of the frame of the steps
You need to start by installing the filly. Typically, for stairs of this type, supports are made from a corner with a shelf width of up to 40 mm. A section of this profile must be bent at a right angle. In this case, the dimensions of the horizontal and vertical parts are strictly maintained. In our example, respectively 28 and 18 cm.
Fillings are welded by electric welding in places that were determined during the calculation. If there are two braces in the staircase construction, then first the supports are fastened to one of them, then the second channel is applied to the first, due to which the exact installation locations of the filly on the second are determined. If the distance between the two load-bearing beams is large, it is recommended to install transverse profiles (corners) between them at the level of filly mounting, which will increase the rigidity and reliability of the entire staircase structure.
This is the simplest frame for stairs, which you can quickly do with your own hands. There are a large number of varieties of supports, which are made of pipes, iron sheet, steel reinforcement and other profiles.
In the design with one kosour, you can use the filly in the form of a vertically mounted profile at the level of the outer edge of the step. Its height will be equal to the height of the approach. At the same time, the frame itself is installed on this stand with one side, and the opposite on the side. In the photo below, this option is shown. It is necessary to clarify that such a design is possible only if a metal frame is installed under the steps.
Setting steps
As for the fastening of steps, then everything will depend on what material they are made of. If this is wood, then the easiest way is to fasten it with screws or bolts. In both cases, you will have to make holes for the fasteners in the filly or in the frame.
- If self-tapping screws are used as a fastener, then they must be selected along the length slightly less than the thickness of the step. They are screwed into the wood from the bottom side, while it is recommended to put a rubber gasket and a wide washer under the fastener cap.
- If bolts are used, then, first of all, the place of fastening is determined on the steps. To do this, they are laid on a frame or filly and from below through the holes with a marker mark the places of the through holes in which they are made with a drill and a drill. The diameter of the drill should be slightly larger than the diameter of the bolts. On the front side under the fastener cap, a recess is made to the thickness of the head and a diameter equal to the width of the cap. The step is installed in place, a bolt is inserted into it from above, which is screwed down with a nut through the filly or frame. In this case, the head of the fastener will go into the expanded hole and become flush with the surface of the step.
If the steps are made of metal, then a reliable method of fastening is electric welding. Although the construction will also hold well on bolts. True, this is a more difficult option, because you have to make a large number of holes in metal profiles. This applies to the filly with the skeleton, and the steps themselves. In addition, after such a connection, it will be necessary to hide the bolt heads (paint or put on plastic caps).
Installation of fences
And the last final stage is the installation of the building envelope. In this category, a rather large assortment that will perfectly harmonize with the metal frame of the stairs. Here are just a few popular options:
- forged;
- wooden;
- aluminum;
- from stainless profiles, the pipe is more often used;
- plastic;
- glass.
The main requirement for the choice is full compliance with the design of the staircase itself on the kosoura. But if we talk about the installation conditions, then stainless steel and plastic fences are suitable in case of self-installation. Installation of the remaining structures is best entrusted to professionals.
Making and building a staircase on the kosoura with your own hands with seeming simplicity is a complex process. Therefore, it is very important to accurately calculate, it is better to make a drawing on paper, which will become the starting point of installation operations.