In terms of functionality, stairs are necessary for vertical movement, for example, from one floor to another.
By appointment and use, all types of ladders are divided into:
- main (marching);
- central aisle (or ceremonial);
- intra-apartment (located in multi-level apartments or in a private house);
- park and garden.
roofing (installed on pitched roofs, used for safe installation work and maintenance);
emergency evacuation (for emergency and rescue work);
service (set for access to the basement and attic);
Spiral staircases are most often intraroom, because they are installed either in a multi-level apartment or in a private house. An interesting solution would be to install a spare escape spiral staircase on one of the outer walls of the house. Concrete spiral staircase will be an interesting and functional attribute of the exterior facade of the house. Spiral staircases are installed in basement and attic rooms: they take up less space than flight staircases and look more original.
The material for the manufacture of stairs can be anything: from stone to plastic. The choice of material is determined by the functional purpose of the ladder and its operating conditions.
Variants of stairs from different materials:
- from natural and artificial materials (tile, porcelain stoneware, marble, granite, etc.);
- metal and steel (copper, steel alloys, aluminum alloys are used; artistic forging is often used in the manufacture of metal stairs);
- concrete (reinforced concrete);
- glass (often combined).
Often stairs are made of wood, metal alloy or glass. Less often - marble and concrete. Designers create different versions of the layout of materials (railings and the foundations of the stairs), often there are combinations of glass and metal, stone and wood, glass and stone, wood and glass, and so on.
The choice of material depends on the style in the interior. Wood is an almost universal material. Suitable for use in various conditions (indoor and outdoor). Wood combines well with other materials, so it is not difficult to combine wooden steps and handrails made of transparent glass, to create concrete steps and beautiful forged fences and railings.
Types of spiral staircases
Of all the diversity can distinguish the main types of spiral staircases, four of them:
- The stairs are supported on the walls. The steps are wedge-shaped (narrow at one end, wide at the other). The wide end of the steps is attached to the bearing wall, the narrow end to the support pole (you can do without it). Such spiral staircases are installed on the second floor or in the basement, as most often located in the corner of the room. Fences are needed only on the top platform.
- A ladder with a support on an internal column in the center of the structure with a cantilever fastening (modular ladder). This fastening is called console (or modular), because each of the steps has a knot at the narrow end facing the center. Each node is inserted into the other, with the appearance of a constructor. Such models of stairs are most popular in private houses and country houses. It is easy to assemble and assemble, and the design ideas of such a ladder are not limited to anything. The modular spiral staircase is absolutely not tied to the wall, so it can even be located in the center of the room. It is advisable to install fences around the circumference of the entire staircase.
- Ladder with a support on a monolithic central column. It differs only in that the steps are attached to a monolithic concrete or metal pillar. Popular cast-iron spiral staircases of this model. Forged spiral staircases are durable, can be used both in the apartment and in the country.
- Staircase without support on the central pillar and walls. This is the most original design of the spiral staircase, especially for a private building. Designers came up with a method of fixing the steps of a spiral staircase on a special way of curved bowstrings or kosoura (these are the bearing elements of the stairs).
Spiral stairs of the second and third models can be manufactured and installed independently, modular stairs are very easy to assemble. But the fourth option requires special attention and skill; therefore, it is better not to engage in independent design, manufacturing and installation, but to entrust this business to professionals.
The presence and absence of handrails, railings and fences does not depend on the type of construction. For aesthetic reasons, you can opt out of the handrails, but for security reasons, experts recommend installing them. Cast-iron spiral staircases are often made immediately with railings.
Spiral staircases in the interiors
Various models of spiral staircases look great in any interior - from luxurious baroque to classic Victorian. Steel spiral staircases will be appropriate in laconic minimalism and expressive fusion-style. The spiral glass staircase looks delightfully in the high-tech interior, and the white stone staircase will become an integral part of the Mediterranean interior.
In a private house or a multi-level apartment spiral staircases look more interesting than marching. There are several advantages:
- Compactness. This is especially important in the apartment.
- Originality. Spiral stairs to give can be supplemented with a pole in the span or slide for a quick descent. This idea will love the children.
- Spiral staircase design. Steel, concrete, wood, glass, plastic, stone, combined - there are hundreds of types of spiral staircases. It will not be difficult to find refined cast-iron handrails that are suitable in color to wooden or concrete steps. You can order original glass fences, made of transparent or frosted glass, with a pattern or stained glass painting. You can leave the handrails or combine them with fences, you can leave the fences or completely abandon it. In any case, the spiral staircase will look interesting and original in any interior.
- Price. As a rule, standard spiral staircases are slightly cheaper than marching.
Spiral staircase dimensions
The formula for the safest ladder was derived in an experienced and practical way: 2a + b = 600 ~ 640 mm. In this formula, a is the step height, b is the step width, 600 ~ 640 mm is the average step size of a person on a horizontal flat surface.
The width of the step should provide support for the entire length of the foot, on average from 200 mm to 340 mm. The height of the step should not exceed 250 mm, the optimum height is from 150 mm to 200 mm. Given the wedge-shaped steps, at the point of support on the central bearing pillar, the width should not be less than 100 mm.
The length of the steps depends on the purpose of the stairs:
- less than 80 cm is considered not comfortable even for 1 person, but is suitable for a fire escape;
- from 80 cm to 100 cm (1 m) will be optimal for the stairs leading to the second floor, attic or basement;
- step length of 100 cm or more is considered comfortable for the passage of two people.
Standard ladders are most often made with a width of a step (tread) of 300 mm and a height of 150 mm. Step width can be increased by overhanging the top step above the bottom. But in this case, the width of the hanging part should not exceed 50 mm if the structures are steel and 30 mm if they are wooden spiral staircases.
It is important to remember about the angle of inclination of the spiral staircase. The safest angle is from 25 ° to 35 °. If the inclination angle is more than 40 °, then the descent from the spiral staircase will be problematic, and if the angle is more than 45 °, then the descent can be carried out only forward backwards (steps are too steep).
The opening on the upper floor must be at least 2 m, especially if the staircase is the main one and is often operated, for example, to climb to the upper floor. The length of the steps in this case (if the opening is about 2 meters in diameter) will be 80-90 cm, because part of the length will be “eaten” by fixing the support column, the railings and fences will be placed. Considering the fanlike arrangement of steps and the effect of overhanging of the upper steps above the lower ones, no more than 65 cm (650 mm) will be allotted for walking. The secondary staircase options used rarely have an opening of 130-140 cm.
The project of a spiral staircase: calculations
- The size of the expected opening of the upper floor:
for the main staircase not less than 2000 mm (2 m), for the “spare” - 1300 - 1500 mm (1.3 - 1.5 m).
You can not push off from the width of the opening, but from the desired diameter of the stairs, based on the width of the march (the value that determines the width of the mid-flight ladder; in our case, the spiral one, if it is “unrolled”).
- The height of the future staircase (the height of the interfloor space).
- Torsion angle. For a spiral staircase in the middle of a room, angles from 270 ° to 360 ° are most often used.
For the construction of the stairs, it is necessary to determine the number of steps, their length, width and the distance between them (height).
Assume that the height of the ladder should be 3 m, and the width of the march - 90 cm. We translate the values into millimeters (mm) for ease of calculation: 3 m = 3000 mm; 90 cm = 900 mm. On the railing will take about 100 mm. The overall diameter of the spiral staircase is easy to calculate by the formula: D = 2a + 200 mm, where a is the width of the march of the future ladder, and 200 mm is the diameter of the support column in the center of the structure (it is not recommended to make it less than 20 cm in diameter). We get:
D = 2a + 200 mm = 2 * 900 mm + 200 mm = 1800 mm + 200 mm = 2000 mm (2 m)
If the height is 3000 mm and the optimum height of the steps is 150-200 mm, then we get:
3000 mm / 150 mm = 20 steps
3000 mm / 200 mm = 15 steps
If you stop at 15 steps, then you will need 14 steps for lifting + 15 level - the upper platform. Using the formula 2a + b = 600 ~ 640 mm, choose a larger value - 640 mm, you can calculate the width of the steps:
2 * 200 mm + b = 640 mm
b = 640 - 400 = 240 mm
The step width will be 240 mm, which meets the safety requirements of the stairs.