A compact spiral staircase becomes a familiar interior solution for country houses. This graceful design will decorate any room and help to preserve the usable area in buildings with limited dimensions.
To make a standard spiral staircase to the second floor with one's own hands is quite within the power of anyone. The main condition for the successful integration of this design into the interfloor space is the correct calculation of all product parameters.
The calculation of the spiral staircase to the second floor is recommended to start with a sketch or drawing, which will then become a step-by-step production plan for this product.
There are three main types of spiral staircases that are used for country houses:
- With a central support column to which steps are mounted in various ways.
- With steps mounted on a bowstring without a central support.
- Combined mounting of steps on bowstrings and support pillar.
In buildings intended for individual housing, the first method is most often used. Further examples of calculating a spiral staircase will be based on just such a design.
A drawing of a spiral staircase with the dimensions printed on it will avoid installation errors.
Start to calculate the flight of stairs with determination of radius and circumference.
The plan of the stairs from above looks like a regular circle with a diameter corresponding to the size of the opening in the floor. The radius of this opening is usually denoted by the letter R.
The radius of the support pipe is denoted as R1. This size also includes the pipe wall thickness. To organize a screw structure, it is recommended to use a steel pipe with a diameter of at least 60 mm and a wall thickness of 5 mm or more.
As interstage dividers, as well as to provide fasteners for the narrow end of the stage, pipe segments with a larger diameter than the diameter of the support column and a height equal to the height of the steps are used.
The next step is to calculate the number of turns of the stairs. If the march makes two full turns (n = 2), this corresponds to 720 degrees, which indicate at.
When calculating the number of revolutions, it is necessary to take into account the optimal height for a person's free passage. It should be 185-190 cm, which will allow you not to hit your head on the upper steps.
For example, with a height from the floor of the first floor to the floor of the second floor of 5 meters and the number of revolutions n = 2, the height between the turns of the flight of stairs will be 2.5 meters. Which is quite enough.
If the floor height does not allow a full revolution, the value in fractions of the whole revolution is used for further calculations in the formulas. For example: 2 / 3n, 3 / 4n.
To calculate the outer circumference, you must use the formula: L = 2 * 3.14 * R * n. If R = 1 m, then L = 2 * 3.14 * 1 * 2 = 12.56 m.
It must be understood that a person will not move along the stairs along the outer edge, but approximately in the middle of the step width. In order to understand how to calculate the middle line of the steps of a spiral staircase, it should be remembered that for spiral stairs you need to take the calculated distance 2 * R / 3.
Thus, we obtain another quantity - the circumference of the path of human movement (I) It can be calculated by the formula: I = 2 * 3.14 * (2 * R / 3) * n, which in our case is: I = 2 * 3, 14 * (2 * 1/3) * 2 = 8.37 m.
Calculation of the height of the steps and their required number
How to calculate the steps of a spiral staircase? You should measure the height from the floor surface of the first floor to the ceiling (H1) and add the thickness of the concrete or wood floors (H2) Assume that the height H1 = 5 m, and H2 = 0.25 m, it turns out that the total height H = 5 + 0.25 = 5.25 m.
The normal dimensions of the steps are: height - not more than 20 cm, width - not less than 27 cm, overhang - not more than 4 cm.
Take the step height s = 20 cm.
To determine the number of steps, it is necessary to divide the floor height by the desired step height: x = N / s= 5.25 / 0.2 = 26.25 steps. If the first step is made at a height of 25 cm, the remaining steps will have a height of 20 cm, and the last, 26 step, will correspond to the floor level of the second floor, i.e. be the platform of the stairs.
Calculation of the length of the steps and the width of the tread
An important parameter of the size of a spiral staircase in a private house is the length and width of the steps. Since the screw structure is usually small in size, it must be taken into account that it is convenient for a person to climb along it to the second floor.
Due to the rotary span device, the step itself for a spiral staircase has an irregular, wedge-shaped shape with a wide outer end and a narrow end, which is intended for mounting on a support post.
The calculation of the size of the steps is carried out in stages:
- Initially, the size of the widest, outer part of the step (d1), it is performed slightly rounded. To calculate the indicator d1, you should divide the external length of the stairs by the number of steps: d1 = L / x= 12.56 / 26 = 0.48 m;
- To determine the width of the tread in the midline (d2), in the place where the person will pass, it is necessary to use the circumference of the path I. The calculation scheme remains the same: d2 = I / x= 8.37 / 26 = 0.32 m. This value fits into the standard dimensions of the steps and will be comfortable for moving up the stairs;
- The next step determines the value of the step width near the support pipe (d3) This indicator depends on the diameter of the pipe, but usually it is at least 10 cm;
- If the step is made with a direct outer edge, to determine the maximum width of the step, you need to find the angle (and) according to the formula: a = y / x= 720/26 = 27.69 degrees. Next, the maximum width (from) steps: c = 2 * R * sin a / 2= 2 * 1 * 0.55 / 2 = 0.55 m.
Estimated step length (h) is determined from the bearing support of the stairs to the outer edge. This value is as follows: from the radius of the opening, the radius of the support should be subtracted. R-R1= 1-0.065 = 0.939 m.
The calculated step length does not exceed one meter, therefore, for the manufacture of steps, you can use solid wood. If it turns out that the step length is more than 1 m, it is necessary to provide additional support points for wooden steps, or use standard welded metal structures. If it is necessary to cover a large opening, metal steps are the best solution.
After completing all the step-by-step calculations of the sizes of the steps, you can proceed with their manufacture, but for exact observance of all parameters, you should make a drawing of this part, especially in the case when the order will be handled by an external person or organization.
Calculation of the staircase
The radius of the site is usually slightly less than the radius of the opening, an exception is the method of erecting a spiral staircase with balusters that rest on the outer edge of the steps, in this case the radii will coincide.
If we take the diameter of the opening equal to 200 cm and reduce it by 20 cm (part of the tread used when walking), then the length of the step will be: (200-20) / 2 = 90 cm.
To determine the width of the upper platform, you should consider the loss of height when moving along the march. Each step in our case reduces the distance to the site by 20 cm. Accordingly, it is necessary to calculate the minimum possible height to start organizing the site. If we take the average person’s height of 180 cm, then from the floor level of the second floor where the platform is organized, there will be nine steps to the lower step (180/20 = 9).
In our case, 26 steps account for two full turns, and 13 steps respectively for one (final) one. The width of the site is calculated by the number of steps: 13-9 = 4. This means that the width of the platform will be equal to the width of 4 steps, minus the holes in the middle under the support pillar.
The width of the step d1 is 0.48 m, which means that the width of the platform will be: 0.48 * 4 = 1.92 m, which is quite enough for a comfortable climb. The larger size of the site will not allow a bend to pass freely under it.
Having studied the above calculation methods, each home master will easily figure out how to calculate the spiral staircase to the second floor and make all the necessary structural elements yourself. For faster counting, you can use special programs that allow you to accurately and quickly calculate the parameters of a spiral staircase.