In suburban areas today, in order to save money, they build mainly houses with two or three floors. In any case, there is an attic in almost every private residential building. And this means that an almost obligatory element of any country house is a staircase. When designing such a structure, one should also decide on such a parameter as the height of the step. You also need to correctly calculate the width of the rises of the march, their length and some other indicators. It is imperative to draw up a staircase project taking into account the requirements of SNiP and GOST.
What are the stairs
In country houses, two types of lifting structures are usually installed - ordinary marching or screw ones. The first variety can also be rotary. Thus, there are also two types of steps - simple square (or semicircular) and trapezoidal.
It often happens that there is not enough space in the house to equip the turntable platform. In this case, it is replaced with running steps. In fact, such stairs are a transitional option from mid-flight to spiral. ATtheir designs use both types of lifts - both trapezoidal and rectangular.
Standard sizes
GOST and SNiP standards mainly determine the width and height of the steps of concrete stairs of multi-storey city buildings. The first indicator according to the standards should be 30 cm. Such a parameter as the height of the stairs, GOST prescribes to be determined taking into account the angle of inclination of the march. So, for access stairs, this figure is usually 125-145 mm. For steeper basement and attic structures, the lifting height should be 143 or 168 mm. The width of the steps for such stairs can be reduced to 26 cm.
In a private house, this standard is strictly observed, of course, not necessary. For such buildings, the specific width and height of the stairs are not determined by GOST. There are only certain limits of values, beyond which it is not recommended. When designing stairs in country houses, they pay attention primarily to the features of the layout of the premises.
Step design
Stair lifts can be attached to bowstrings or stringers. In both cases, reliable and durable marches are obtained. Structurally, the steps consist of two main elements:
- tread (horizontal part);
- riser (vertical part).
The width of the flight of stairs, according to the regulations, should not be less than 0.9 m. But usually in private houses they assemble structures with a distance from the railing to the wall of about 1.2-1.5 m. The length and height of the stepsthe stairs are in no way interconnected. Other factors are taken into account when calculating lift parameters.
The riser is sometimes not included in the design of the stairs at all. This saves on material. However, marches without such an element look less solid and safe compared to ordinary deaf marches.
Regulations
When designing, you must adhere to the following rules provided for by SNiP for mid-flight stairs:
- tread width should not be less than 20 cm;
- the upper step can hang over the lower one by no more than 5 cm;
- the height of the stairs should not go beyond 14-21 cm.
Screw structures are designed taking into account the fact that:
- the narrowest part of the steps should not be less than 10cm;
- the width of the trapezoidal step on the opposite side should not exceed 40 cm;
- on the central axis, the tread should be at least 20 cm wide.
Calculation formula
The required width (A) and step height (S) of the stairs are calculated according to the formula 2S + A=590…650 mm. The range of numbers from 590 to 600 mm is the average length of a person's step. Thus, depending on the layout of the house, they are first determined with such a parameter as the height of the step. Next, calculate the required number of lifts, find their width and the optimal angle of inclination of the march.
Calculation example
Let's say the floor-to-ceiling distance in the roomis 275 cm. In this case, the desired step height is 17 cm. In this case, the number of rises will be 275/17 - 1=16.18 - 1=15.18. Rounding up to a whole number, we get 15 steps. Find the actual lift height 275/16=17.2 cm.
Now you can determine the width of the step. A \u003d 63 cm - 217, 2 cm \u003d 28.6 cm, rounded up to 29 cm. Next, you need to determine the projection on the floor. To do this, simply multiply the width of the steps by their number. As a result, in our example, it turns out that the first step should be 1529=435 cm from the wall. Knowing the height and projection, we can first determine the tangent tgA=275/435=0.6321, and then the angle of inclination itself A=32 degrees 18 min. This is within the allowed parameters.
What you should know
Very often the stairs in the house are designed even before such an operation as finishing the floor. In this case, the thickness of the future flooring and insulation (if provided) must be added to the height parameter. All steps in the march must have the same height. Otherwise, moving up the stairs will be extremely inconvenient and also unsafe.
In addition to the minimum and maximum allowable indicators, there are also optimal march step heights. This parameter is 17 cm. The optimal width of this structural element of the stairs is 28 cm.
Height of steps of marches made of different materials
Determining the parameters of the rise of the stairs, one more important factor should be taken into account. The height and width of the steps may depend, among other things,and from the material chosen for the manufacture of the march. This rule does not apply mainly only to concrete and metal stairs.
Standard edged board width, for example, is 150, 175 or 200mm. Accordingly, the height of the step in this case will be equal to one of these values (minus the thickness of the lumber). In this case, it is not advisable to choose another parameter. Otherwise, you will have to do too much laborious work to reduce the width of the boards.
The same goes for climbing brick stairs. It is most convenient to assemble the steps of such structures in two rows. In this case, first the bricks are laid out on the bed. In the second row they are placed on a spoon. The height of a standard brick is 65 mm, the width is 120 mm. As a result, we get a rise of 65 + 120 + 10=195 mm (5 mm for the seams).
Vertical stairs
Such designs are rare, but used in private homes. Usually these are either attic stairs, or leading to cellars. The allowable range of distances between bowstrings in this case is 0.45-0.80 m. The height of the steps (the step between them) should not be less than 0.30 m and more than 0.34 m. The maximum length of the vertical ladder itself is 5 meters.
Such a design must be equipped with a device that prevents it from shifting and tipping over. Approximately the same requirements apply to ladders.
What other regulations exist
Of course, SNiPs determine not only the height of the step and its widthshould be centimeters. When designing stairs, be sure to take into account other standards:
- railing height should not be less than 90 cm;
- the distance between the balusters cannot be more than 15 cm;
- minimum board thickness for tread is 2.5-3 cm.
When designing the turning stairs of private houses, among other things, one should pay attention to such an indicator as the height of the platform above the floor. According to the standards, this parameter should not be less than 1.9 m. But it is still better to place the platform between the marches higher - 2.5 m from the floor. Otherwise, people of normal height passing under the stairs may simply get hit.
In wooden lifting structures, all elements should be fastened with bolts. When using self-tapping screws, the ladder will loosen very quickly. The first step is allowed to be done a little higher than the rest. In the march itself, there should be no more than 18 ascents. However, it is desirable to turn such long stairs. Moreover, each march can have 9 steps (or, for example, 5 and 13). The depth of the upper landing of the stairs is determined by the width of the door leading into the room. The first parameter must be greater than the second.
