Internal and external stairs are available in almost every home. Assembling such structures should be done with preliminary drafting. When developing drawings, it is important to comply with all the standards provided for by SNiP and GOST. In particular, this applies to such an element of the design of the stairs as steps. They must be first and foremost strong and reliable. The sizes of the steps of the flight of stairs and the opening should be selected in such a way that it was convenient to move around. In addition, their design should also be as safe as possible.
Types of stairs
In the courtyards and in the internal premises of houses lifting structures of the following varieties can be installed:
- Marching. This is the most common type of stairs. Their steps are usually attached to a kosour or bowstring. Marching stairs can be simple and rotary. If it is impossible to equip the site due to lack of free space, such structures are made curved using cross-section steps.
- Screw. This option looks more modern than marching and takes up much less space. Spiral staircases can be installed in any part of the house or yard, and not just against the wall. They usually have a round shape. The steps in such stairs are trapezoidal and are attached to the central pole. Sometimes rectangular spiral staircases are also installed in houses and courtyards. In this case, two sites are included in their design. Unfortunately, this option is cumbersome, and therefore it is used very rarely.
- Vertical. This type of staircase is usually used as a firefighter, to climb unheated attics or to descend into the cellars. Such stairs are simply two supports, between which the crossbars are packed. There are two main varieties of them: attached and stationary. Often such stairs are foldable.
Marching rotary stairs are quarter (90 degrees) and half-turn (180 degrees). Screw constructions, in fact, are their variety. The rotation of such stairs is 180 g. Next, we will see what in all these cases the sizes of the steps can be. GOST defines exact indicators mainly only for stairs of multi-storey buildings. In particular, in most cases, the optimal (but not beyond the scope of SNiP requirements) width, length, depth and height are selected.
General requirements
When assembling stairs of any type, the following general rules should be observed:
- The number of steps in one march should not exceed 17 pcs. Their minimum number can be any. But usually in the stairs there are at least 3 steps. The safest marches are with an odd number of them.
- The height of the stairs should be the same. Only the first can be a little higher than the rest.
- Releasing a step too large is not allowed. Otherwise, a person walking up the stairs may simply stumble. The regulations provide for an exhaust length of not more than 30 mm.
- The distance from the upper step to the front door should be at least 1 m. In any case, it is not allowed to make a platform narrower than the width of the front door.
Features of the design of steps
This main element of the staircase consists of two main parts:
- horizontal support treads;
- vertical risers.
The width of the first and the height of the second when compiling the project should be calculated as carefully as possible. The convenience and safety of the march mainly depend on these two indicators. Sometimes stairs are done without risers. Such designs cost less, but they look less thoroughly.
Length of steps
The stairs leading to the house or to the rooms, according to the norms of SNiP, are supposed to be quite wide. Standard steps, the dimensions of which are determined by GOST, have a length of at least 90 cm. But an indicator of 1-1.5 meters is considered the best option. On such a march, people descending and ascending will be able to disperse in comfort.
March depth
The optimal width of the stairs leading to the living quarters is considered to be 30 cm. In any case, according to the standards, this indicator should not be less than 25 cm (for the basement - 26 cm). That is, the width of the tread must be made so that the foot of an adult is freely placed on it.
An exception to this rule are only spiral and vertical staircases. The narrow side of the trapezoidal steps should have a width of at least 10 cm. Vertical stairs, and especially attached, should be as mobile and light as possible. Therefore, the width of their steps is not regulated by standards. Most often, this figure is 5-10 cm. In metal fire structures, steps can even be made of a thick rod with a diameter of 15-20 mm.
What should be the height?
When calculating this indicator, the angle of inclination of the march should be taken into account. GOST for the dimensions of the steps of a concrete staircase in multi-storey buildings, for example, provides for the following ratios:
- for structures with a slope of 1: 2 - 125-145 mm;
- with a slope of 1: 1.5 - 143 or 168 mm.
The last version of the stairs is usually used for lowering into the basement or climbing to the attic. The width of the tread in the driveway concrete structures is always 30 cm. At the basement and attic stairs - 26 cm.
In private homes, steps are usually made 150-200 mm high. It is this range that is allowed by SNiP standards. The optimal height option depends mainly on the growth of people living in the house and the width of their stride.
Step sizes: how to make calculations of optimal performance?
When designing an external or internal staircase, the following formulas are usually used:
- A + B = 450 mm (reliability of the march);
- VA = 120 mm (safety).
“A” in this case is the riser height, “B” is the width of the tread. The ratio of the sizes of the elements of an ideal march for safety and reliability is calculated by the formula 2A + B = 600 mm.
The dimensions of the steps of the stairs of the house depend, inter alia, on the material used for its manufacture. So, for example, the standard width of the board is 75-275 mm with a gradation of 25 mm. For treads, both 250 mm and 275 mm material are suitable. Wider boards in this case, it is impractical to use. For risers, they usually take 150, 175 or 200 mm material. In this case, the second and last options are considered the most convenient.
In brick stairs, steps most often have a width of 250 mm. Their height in most cases is 177-178 mm. Such dimensions of the stair steps are determined by the dimensions of the material itself (length 250 mm, height 88 mm). When laying structures of this variety, they are usually made two bricks high. That is, 88 you just need to multiply by 2 and add 1-2 cm to the seams.
For steps of metal and concrete stairs, the necessary parameters of length, width, etc. are determined only by the cost of the material and ease of use.
What else should be considered?
We have figured out what the standard and optimal sizes of the steps should be. However, when designing the stairs, it is worth considering another important indicator. When choosing a material for wooden structures, it is worth paying attention to its thickness. Of course, too thin boards for the stairs should not be taken. Otherwise, it will turn out to be unsafe and also short-lived.
The thickness of the wooden tread is determined by the ratio of 1:20 to its width. This provides a sufficient margin of safety. That is, a step board with a width of 250 mm should have a thickness of at least 12.5 mm. For risers, you can use thinner material. Edged boards with a thickness of a centimeter in this case is usually quite enough. Sometimes the vertical space between the steps is covered with just plywood.
Concrete stairs at the final stage are usually tiled. Therefore, when calculating the height and width of their steps, it is necessary to take into account the thickness of this material. For tiles, this indicator is usually 4-9 mm. Natural stone tiles can have a much greater thickness of 1-2 cm.
Conclusion
Subject to all the above rules, in the house or in the yard you can assemble the most convenient and durable stairs. Of course, correctly calculating the size of the steps is only half the battle. When assembling the stairs, you should correctly select the height of the railing (at least 90 cm), the methods of fastening the elements (only bolts for wood), the angle of inclination, etc. However, it is the reliability of the steps that mainly determines the safety and comfort of such structures. And this means that it is not worth saving in the material and going beyond the permissible indicators of length, width, height and thickness in this case.