Any interfloor staircase should be not only aesthetically attractive, but also safe, as well as convenient for people to move. Designing such a design in the house needs to be done correctly. Risers and treads, marches, stair rails must comply with certain standards.
Main varieties
There are two types of such structures in private two- and three-story houses: screw and marching. The latter type of stairs has a solid appearance and is considered more convenient to use. At the same time, screw structures occupy less space in the building. They are usually installed in rooms not too large in area.
In any case, the main element of any staircase is the stairs. When designing this particular part of the lifting structure, special attention is usually given.
What are treads and risers
The steps of the stairs should be, firstly, deep enough to fit the human foot on them. Secondly, they should not be too low or, conversely, high. Otherwise, walking up the stairs will be uncomfortable and dangerous. The steps consist of two main elements:
When moving up the stairs, a person’s foot rests precisely on the tread. Risers are considered an additional element. In the design of the stairs, they play mainly a decorative role. With them, marches look more solid and safe.
Sometimes stairs are built in the house without risers. Such designs are cheaper. But when designing stairs without risers, maximum attention should be paid to its design. Otherwise, such a design will not look too attractive.
Dimensions of stairs. Safety formula
What should be the steps of any home lifting structure? When designing stairs, the safety formula should be taken into account first. It looks like this:
Here h is the riser height, b is the tread width, S is the person’s step length. The last parameter averages 63 cm. Thus, with an increase in the riser height h by 1 cm, the width of the tread must be reduced by 2 cm.
Sizes of steps. Regulations
According to the rules provided by SNiP, in order for the staircase to be safe, the height of its risers should not be less than 15 cm and more than 18 cm. The minimum tread width is 29-30 cm.
Such parameters are provided for the main stairs in the house. When designing auxiliary lifting structures (attic and basement), since they are not used too often, such strict rules are usually not respected. But even for such stairs, the lengths and heights of the steps must comply with certain standards.
So, for example, the height of the risers for attic and basement structures should be approximately 17.1 cm.The width of the treads at the stairs of this type should not be less than 26 cm.
The minimum step length (march width) of a conventional interfloor lifting structure is considered to be 90 cm. In this case, 2 people can freely climb the stairs. Attic and basement marches can be narrower.
Spiral staircases
The standards discussed above are valid mainly for marching stairs. When designing their risers and treads, you should be especially careful. The same applies, of course, to spiral staircases. In structures of this type of risers, most often it is not provided at all. At the same time, the steps at the stairs of this variety have a trapezoidal shape. When designing screw structures, the following standards should be taken into account:
the width of the tread in the middle should not be less than 20-25 cm;
minimum tread width at a distance of 15 cm from the rack - 10 cm;
- from the edge far from the rack, the width of the tread should not exceed 40 cm;
riser height (step lifting) - 15-20 cm.
The optimal length of the steps of a spiral staircase, like the march, are considered 90 cm.
Tilt angle
Steps with their main elements - risers and treads - thus, are the main part of any staircase. If they are designed correctly, the lifting structure can already be considered comfortable enough for movement. But the marches themselves of such structures should, of course, be safe. Their minimum width, as already mentioned, is 90 cm. When designing flight stairs, the angle of inclination should also be observed:
for standard interfloor - 30-45 degrees;
for attic, basement and temporary - 45-75 degrees;
for porches - 30 degrees;
for attached structures - over 75 degrees.
Number of steps and marches
Stairs should not be too short or long. It is also believed that it is best if the number of steps in them is odd. It is usually much more convenient for people to start and end the movement with one leg.
However, the rule is optional. The shortest stairs usually have 3 steps. The longest marches consist of 18. If such a length of stairs is not enough, it is divided into two halves, between which they equip the site.
It is believed that the distance between the marches of the swinging oncoming structures in the house should be at least 5 cm. If the railing handrails are located close to the braids or bowstrings of the upper part of the stairs, people moving on it can damage their fingers.
Other rules
When designing staircases, the following standards should also be observed:
If there is a lift for the disabled in the staircase construction, its march width should be at least 1.5 m.