Designing a spiral staircase online. We calculate the spiral staircase on our own. Calculation of a spiral staircase on an example

A spiral staircase is usually installed in cases where it is necessary to save space or complement the interior. Perfect for giving or a private house as a staircase to the second floor, attic or attic. Can be collected in the smallest areas. Inferior in compactness except that a folding ladder.

The design of spiral staircases is not very practical. It is difficult to carry oversized things to the 2nd floor along it, and you are unlikely to miss each other with a person walking towards you, unless, of course, this is a monolithic concrete structure. You should also be aware of the difficulties that pensioners or young children face when climbing a steep march.

A spiral staircase can be either wooden or metal. Very often these materials are combined to combine best qualities each of them.

If you have weighed all the pros and cons and decided to do it, you first need to calculate the steps of the stairs.

Dimensions of the spiral staircase to the second floor of the house

H - the height of the stairs is the sum of the distance to the ceiling and the thickness of the ceiling;
H 1 - the distance between the turns;
h is the step height;
h 1 - the depth of the step or tread;
R is the outer radius;
R 1 - radius of the main line of rise;
r is the radius of the inner support.

Considering that the safety of the structure is in the first place and following the requirements of GOST, SNiP and other standards, it is necessary to take into account the restrictions on the parameters and dimensions of the steps:

the distance between the turns of H 1 must be no less than the height of a person, otherwise, you will beat your head on the step above you. The recommended value is at least 2 m;
it must be remembered that the movement is carried out mainly along the line of ascent, which is approximately a third of its radius from the outer edge of the step. In this place, the depth of the tread should be the most convenient - from 20 to 30 cm;
the width of the step near the central support should not be less than 10 cm;
for safety reasons diameter spiral staircase must be either at least three meters, or the installation of railings is mandatory. The height of the handrail is 90 - 100 cm.
to save space, often, risers are not used, but the distance between the steps should be within safe limits, that is, from 12 to 22 cm.

How to calculate a spiral staircase - calculation of a flight of stairs

The design of a spiral staircase requires careful planning. Only if the calculations are correct, the product will be safe, convenient and attractive in appearance. For convenience, you can draw up a diagram with dimensions and use it to calculate the stairs for the house.

First you need to determine the area of the site on which the product will be located, since the minimum dimensions and the calculation of the turning staircase as a whole depend on this. Next, measure the distance between the floor of the first and second floors, as well as the thickness of the ceiling, that is, the height of the stairs. Decide where you will have an entrance, and where an exit - the angle at which the flight of stairs twists will depend on this.

When all preliminary measurements are made, it is necessary to determine the number of steps. Suppose that we need to calculate a spiral staircase with a radius of 1 m, a height of 3 m and a twist angle of 360 ° (the entrance to the staircase is located strictly under the exit).

R = 1000 mm, H = 3000 mm, ω = 360°;

To do this, we find the length of the march (L) along the main line of ascent. It will be equal to 2πR 1, while R 1 \u003d 2/3 R, since this line recedes from the outer edge of the stairs by about a third of the radius. Substituting our values into the formula:

L = 2πR 1 = 4/3πR = 4/3 * 3.14 * 1000 = 4190 mm(All calculations are in millimeters).

It turns out that the circumference (L) is 4.19 m. Now we divide the resulting number by the depth of the tread (h 1), for example, 25 cm.

n \u003d L / h 1 \u003d 4190 / 250 \u003d 16.796

Rounding off the answer, it turns out that we should have 17 steps. Given that the latter coincides with the floor of the second floor, we reduce the total number of steps by one. That is, for one turn we need 16 steps.

We take the depth of the tread at the central support for 10 cm (minimum value), and calculate the outer one using the formula:

h 1 ext = L in / n, Where

L in \u003d 2πR \u003d 2 * 3.14 * 1000 \u003d 6280 mm substitute in the initial formula

h 1 ext \u003d 7536 / 17 \u003d 0.369 m \u003d 369 mm- tread depth at the outer edge (shown in the photo).

The height of the riser is determined by dividing the total height of the stairs (H) by the number of steps:

h = H / n = 3000 / 17 = 176 mm

You can slightly adjust the size of the steps, while observing the reference formula - 2h + h 1 = 60..65 cm- the sum of the depth and twice the height of the step should be approximately 60 - 65 cm. Let's try to increase the height of the riser to 19 cm and check according to the standards:

2 * 190 + 250 = 630mm- satisfactory

Since risers are usually not used in structures of this form, it is possible to slightly increase the distance between the steps and thereby make small adjustments to the size of the stairs.

To better understand the material, watch the video on how to calculate the stairs:

Calculation of the landing of the stairs and the height of the stairway

Particular attention should be paid to the calculation of the site on the second floor. In the case of a 360° turn, the start is directly below this platform (exit). When climbing each step, the distance to it decreases by the height of the step, that is, by 19 cm (in our case). Having overcome 4 steps, the height loss will be about 76 cm. Taking into account the thickness of the ceiling (h p), about 2 meters remain in stock. That is, the width of the landing may well be equal to the width of 4 steps, but no more. After all, if you increase it to five steps, then the distance to the ceiling will be less than 2 meters. In this case, a tall person will cling to his head, which is unacceptable.

H 1 \u003d H - 4h - h p \u003d 300 - 76 - 20 \u003d 204 cm- satisfactory

H 1 \u003d H - 5h - h p \u003d 300 - 95 - 20 \u003d 185 cm- not suitable

Designing a spiral staircase - diagrams and drawings

The design of spiral staircases can also be done through special programs. This method is more time-consuming and not everyone wants to understand, model on their own.

Computer calculation of stairs, as a rule, is needed for large-scale construction and is not at all necessary during construction. homemade design. The video will explain how to make a 3d model of a staircase.

Conclusion

The project of a spiral staircase should be thought out to the smallest detail, then the product will turn out to be convenient and safe. It is not recommended to make steps of different sizes. Ascent and descent should in no case create a feeling of discomfort. The materials of parts and assemblies must be strong and fully comply with the loads that the structure will experience. That is, it is necessary to correctly calculate the parameters of the stairs.

IN own house or a two-level apartment cannot do without a staircase, and screw models are currently very popular. Their selection in stores is quite diverse. But if you wish, such a design is quite possible to do it yourself.

To do this, you must first make the correct calculation of spiral staircases. How to do it yourself, we will consider in more detail in this article.

The undoubted advantages of this type of stairs include:

compactness- you can make a very small product that will take up a minimum of usable area in the room.
Price- even ready-made options are affordable for most. And if you make the stairs yourself, then it will cost even less.
Aesthetics- almost any screw design attracts attention with its originality and beauty. You can perform a highly artistic version of the most various materials.

Some of the shortcomings worth noting are the following:

For very compact models, it is inconvenient to carry out the ascent and descent. This must be done very carefully due to the uneven width of the steps.
It is often impossible to move objects of large size along these stairs.
Self-manufacturing or installation individual models- a rather difficult task.

The design of the spiral staircase consists of:

supporting elements;
Step details;
Fencing systems - it does not happen in all models.

With all the variety of spiral staircase products, they can be classified according to several parameters:

View of the step support.
Manufacturing material.
Angle of rotation.

The design and calculation of each type of spiral staircase will have its own characteristics.

Support types

As supporting elements of screw products can be:

Central pillar;
Walls;
Bowstrings;
Kosoura;
Boltsy.

The most common option is the central support. Kosours and bolts are often used. Self-manufacturing of a support bowstring is very difficult.

This requires special equipment and professional skills. For this reason, most will not be able to do this option with their own hands.

Materials for manufacturing

For the manufacture of screw structures, a wide variety of materials can be used:

- ordinary steel, stainless steel, aluminum, cast iron. Steel models are often made from forged metal.
- It is preferable to use hardwood. This is especially true for supporting elements and stairs. Price for wooden crafts usually the most affordable.
- for the most part, such models are performed in private homes with sufficient free space.
Glass- the designs are very aesthetic and original. Such material is perfect to make the stairs a decoration of the house.
Composite materials.

Combined models are widely used. Most often, a combination of wood and metal is used. But a combination of other materials is also possible.

Calculation of the entire structure

Before calculating the structure, it is required to determine the size of the future staircase. First of all, you need to find out what size opening under it can be made.

The minimum opening in the interfloor ceiling is 140 cm, but 200 cm is taken as a standard.
If the structure will be used to move large items, then the diameter of the opening must be at least 220 cm.
Very compact models, for example, for the attic or basement, require a minimum opening.

The size of the structure should be slightly smaller than the diameter of the opening in the floor slab. Next, you need to decide on the type of support and the main steam.

Height

The height of the product will be equal to the distance between the floor of the first and second floors. The distance between the turns of the screw must be greater than the height of a person, at least 190 cm.

In this case, the ascent will be safe and convenient. Depending on the height, the angle of rotation of the structure is selected.

Support

The central support is usually taken metal pipe or wooden pole. Such designs are very original. But the use of a kosour or bowstring is also common. Models on the bolts are very aesthetic.

The diameter of the metal pipe can be at least 6 cm. The wall thickness of the metal support is not less than 5 mm.
A wooden pole is taken with a diameter of more than 15 cm.
The thickness of a bowstring made of hardwood should be at least 4 cm. If pine or spruce is used, at least 6 cm.

At the same time, a combination of various types of support can also be done by hand.

steps

In order for the movement on the stairs to be safe and convenient enough, there are a number of requirements for the elements of the steps:

Width- it must be at least 10 cm at a distance of 15 cm from the inner edge. In the middle of the step, its width is taken more than 20 cm.
Length- if it is supposed to use the stairs as the main and only one in the house, then the minimum size will be 80 cm. When the structure is used as an additional one, or is intended to climb to the attic or descend to the basement, then the length of the steps can be at least 55 cm.

Tip: wooden steps that are less than 100 cm long can be made from durable rocks in a frameless way.

Thickness of each element, made of wood, is taken at least 5 cm with a ladder height of up to 2 m, and 6 cm - with a height of more than 2 m.
lifting height- the distance between adjacent steps is considered optimal if it is within 15 - 20 cm.
The screw design consists of winders, which have a trapezoidal shape.. Their width is uneven. For safety reasons, such structures are mainly performed without risers.

On the central support, the steps are most often overlapped to each other. To ensure greater strength and reliability, additional bolt fasteners can be installed along the outer edge of the consoles.

If a metal spiral staircase is being calculated, then it is better to provide wooden steps. This will greatly facilitate the entire structure and make it more comfortable for movement.

Building a drawing

Instructions for calculation:

First you need to determine the number of turns in the future span. One turn is considered to be a complete wrapping of the march around the axis, it is denoted by "y" and is equal to 360o. Sometimes in calculations it is more convenient to use the dimensionless value of revolutions "n".
We calculate the circumference of the structure along the outer edge of the product using the formula: L = 2 π R * n. You can also apply the formula: L = 2 π R * (y/360).
Since the calculation requires the length of the trajectory of movement "l", instead of the radius of the structure along the edge, we take the radius of the lifting path "r". It will be approximately 2/3R. Therefore, the length of the line of movement will be: l = 2 π *2/3 R * n = 4 π R / 3 * n.
The length of the step is indicated by "h". It is equal to the difference between the radius of the structure R and the radius of the support pipe.
By dividing the height of the stairs by the height between the steps, you can get the number of elements required.
The step angle is the angle between the stairway radii drawn along the edges of the consoles. It is designated "α" and is calculated by the formula: α \u003d y / number of steps.
The maximum step width will be on the outer edge. It is designated "W1". The width of the workpiece is indicated by "W2" The width of the console along the line of movement is "W".
Calculation of the steps of a spiral staircase in width W1 = R * sinα.
We calculate W \u003d r * sin α \u003d (2 R * sin α) / 3. If the result obtained is less than 20 cm, then it is necessary to change the number of steps or the height of the lift. You can also change the rotation of the design.

For specific conditions, it is not difficult to perform the calculation of a spiral staircase with your own hands. After receiving all the necessary data, you can execute the drawing.

Whatever model you choose for your home, you can do all the calculations yourself. In many ways, this task will be facilitated by a special calculator for calculating a spiral staircase. But it is easier to use if you understand the basics of such a calculation well. More information on this topic can be obtained from the video in this article.

When designing and erecting a staircase in a private house to the second floor with your own hands, it is imperative to calculate the entire structure. At the same time, such indicators as the width of the steps, diameter, number are important. All this is very important to consider in order to prepare the correct drawings and make the whole structure ergonomic and completely safe. Such a rather original design is very popular, since its construction does not require a large area, however, in order for the product to be durable and reliable, everything must be carefully thought out and all the nuances taken into account. In addition, the great advantage of the spiral staircase is that it fits into absolutely any interior and becomes its real decoration. To make it convenient to walk on the steps of the fan type, you need to correctly indicate their dimensions. It is quite possible to make a spiral turn absolutely anything, it all depends on the design idea and the availability of free space.

The design of spiral staircases implies the determination of all the required parameters of the product, as well as the preparation of a schematic model of the structure from the symbols. The diagram of a spiral staircase, regardless of its configuration, must be made in vertical and horizontal projection. This will allow you to draw all the main details of the structure completely, as well as determine the advantages and disadvantages of each method of arranging steps.

The ladder can have a very different configuration, namely:

With support on the central axis;
With partial entry of steps into the central support;
With an emphasis on side strings;
console location.

The drawings of each type of staircase will differ from each other, and this must be taken into account when making calculations and drawing up a design plan. At the same time, the sizes of the parts used for spiral staircases differ significantly, since the methods of fastening to one degree or another take away a certain space intended for movement.

Designing a staircase in a private house is a complex process that includes determining the length and width of the flight of stairs, the angle of rotation and inclination of the structure, dimensional characteristics and the number of steps. Let's help you not get confused in this material:.

Functional spiral staircase: drawings and number of steps

Before completing a spiral staircase project, it is worth calculating everything correctly, as well as determining the number of steps. That is why, on the basis of the data obtained, a structure will be developed and erected.

To build a ladder, you need to determine:

Number of steps;
riser height;

Initially, you need to determine the optimal number of steps. The ideal option would be 11-13 steps. There must be an odd number for greater comfort of movement. The count should go from top to bottom. The upper step should act as a platform, and its dimensions do not differ at all from the rest of the existing elements.

To determine the optimal riser height, you need to divide the resulting distance from the ceiling and to the floor by the number of steps. The ideal option would be a step height in the range of 15-20 centimeters.

Winder steps are most suitable for a spiral staircase, which is why, in order to determine the optimal parameters, you must first prepare a drawing.

Calculation of a spiral staircase: design features

A spiral staircase consists of winder steps and is made mainly of wood or metal. There are standard models of spiral staircases that you can make at home or make your own original design, but for this you need to calculate everything correctly and accurately, and also take into account the features of the finished product. Before proceeding with the construction of the structure, you need to choose the optimal type of product.

In particular, spiral staircases can be:

Rectangular;
polygonal;
Round.

Rectangular and polygonal designs can be used if the ladder is mounted next to the wall. If it will be in the middle of the room, then it is best to give preference to a round design. Spiral staircases can be made with or without risers. Stairs without risers are much more convenient to use, since the width of the winder step is much narrower than the foot, so there may be a slip of the foot if the riser is made, since it takes up a certain space.

Important! The absence of risers makes it possible to stand completely with the entire foot on the tread, so the movement along such a ladder will be more convenient and safe.

How to prepare a drawing of a spiral staircase

To prepare a drawing of a spiral staircase, it is important to calculate everything correctly, as well as take into account the dimensions of each structural element.

Before drawing a layout, you need to consider:

Features of the steps;
Tread width;
Opening dimensions.

After reviewing the available ready-made samples, you can choose for yourself best option, which is then slightly modified to fit the existing parameters and features of the interior of the house. One of the main characteristics of the stairs is the width of the tread. To determine this parameter, you need not only prepare a drawing, but also use special formulas that will help determine the required step width.

On the prepared plan, it is necessary to display:

External diameter;
degree of turn;
Tread width.

Additionally, when making calculations, it is necessary to take into account the place for fixing the steps, as well as the area for the railing. In addition, you need to take into account the required area for the design of the opening. When moving up or down, a person of any height should pass easily and freely without touching the ceiling beams. The optimal size of the opening to be equipped should be approximately 2 meters. The minimum diameter is in the range of 1.2-1.5 meters.

How to calculate a spiral staircase online

You can independently carry out all the required calculations and measurements when implementing a spiral staircase project. However, there are special programs that help you quickly and easily take the required measurements, draw up a drawing and visualize the resulting drawings. Thus, it will be possible to get a complete picture of how the finished staircase will look in the interior.

You can come up with the design of the stairs yourself, the main thing is that the design is practical, comfortable and safe. Let's talk about how to do everything yourself:.

In particular, these are such programs as:

Online calculator;
3D constructor;
Autocad.

The most popular and in demand is the online calculator, as well as the AutoCAD program. It is enough to enter only the required data and the program itself will carry out the calculation and offer the most optimal solution. You can get visualization finished construction on all sides, as well as its cuts, which will determine how strong and safe it will be.

If the calculation is carried out in AutoCAD, then it is worth remembering that the finished file will have the dwg extension, which is not compatible with all programs.

Carrying out the design of a spiral staircase

A spiral staircase is installed mainly if you need to save free space.

It is perfect as a ladder for:

Second floor;
Attic;
Attic.

In order to accurately and correctly carry out the design of the structure, all the requirements and norms of GOST are important, as this will make the staircase durable, stable and safe.

The project of a spiral staircase must be thought out very carefully to the smallest detail, so that it turns out to be durable and reliable. Ascent and descent should not cause discomfort. Materials for the manufacture of parts must be durable and fully comply with the loads exerted on the structure.

Determine the size of the spiral staircase (video)

The spiral staircase has a simply excellent design and original look, so it can easily become a decoration for absolutely any home interior, regardless of its stylistic features.

Detail: drawings of spiral staircases (photo examples)

Spiral staircases deservedly attract the attention of private homeowners. This beautiful design will give any home solidity and attractiveness. The technology for making a spiral staircase with your own hands is quite simple. Given the current availability of various building materials to make such a ladder within the power of any owner who has certain knowledge in carpentry. The only point that causes difficulty in creating this original interior element is the determination of the correct dimensions of the spiral staircase in the manufacture of drawings. In this article, we will explain how to calculate the spiral staircase for your home in a quick and practical way.

The main parameters of the stairs: we calculate the steps

The first thing to start with the calculation of a spiral staircase is the correct calculation of the dimensions of the steps of the structure. To do this, you need to navigate legend parameters below:

H is the height of the structure. It is determined by the sum of the distance from the floor to ceilings taking into account their thickness;
H1 is the interturn distance;
h is the height of the steps;
h1 - tread;
R is the outer radius of the step;
R1 - radius along the point of the main line of descent-ascent.

These symbols will later be used in calculations and drawings. It must be remembered that the design of spiral staircases is not an amateur activity. Their parameters, such as diameter, width, or the dimensions of the steps already mentioned, must clearly fit into the existing GOSTs and SNiP norms. Compliance with all requirements for the size of the steps and their other parameters will ensure the safety and strength of the staircase structure. Therefore, in the manufacture of drawings of steps, the following points are always taken into account:

Design subtleties: how to calculate a flight of stairs

The calculation of a spiral staircase is a procedure that requires perseverance. Only 100% correct calculations will turn your idea into a beautiful and safe design. For convenient work on a spiral staircase project, it is advisable to draw up a preliminary diagram with its dimensions, and already carry out all calculations on it. In carrying out such work, special construction calculators can be a good helper - programs that allow you to qualitatively make all calculations of a spiral staircase, even online. They are easy to use, have an intuitive interface and make working on a project a real pleasure.

If online programs are not available to you, you can purchase a disk with such licensed software. This profitable purchase will allow using a computer to create high-quality drawings of building structures according to the specified parameters of width, height, diameter, and other indicators that are entered in special program windows.

The calculation of the flight of stairs should begin with the calculation of the area of \u200b\u200bthe site allotted for the arrangement of the interfloor structure. This important indicator is the main one for determining the minimum diameter of a spiral staircase, as well as for further calculations of the dimensions of the structure.
After that, you should proceed to determine the height of the interior element (H). To do this, as already indicated in the table, measure the distance from the flooring of the first floor to the second, taking into account the thickness of the floor. Here you should also decide on the entry-exit points, which will allow you to determine in the drawing the angle at which the flight of stairs will twist.

Having completed these preliminary measurements, the number of steps should be calculated. For example, we use the conditional calculation of a spiral staircase with a diameter of 2000 mm (radius - 1000 mm), a height of 3500 mm and a vertical angle of twist of 360 degrees. We get: R = 1000; H = 3500; ω=360°.

It is important to note that all measurements and calculations of parameters for drawings using formulas are made exclusively in millimeters!

The calculation algorithm is as follows:

Based on the fact that risers are usually not used in screw structures, it is possible to adjust the distance between the steps in the direction of increasing the gaps. During the adjustment, it should be checked for compliance with the results obtained with the reference dimensions, according to which the double height of the step in total with its depth should fit into the interval from 60 to 65 cm.

We calculate the diameter of the stairs and the width of the landing

At this stage, everything is quite simple. The diameter should always be slightly smaller than the dimensions of the spiral staircase opening. An exception is the option when balusters are installed along the outer edge of the steps. In this case, the width of the stairway may coincide with the diameter of the structure.

For example calculations, let's take the diameter as 220 cm and reduce it to 200 cm (220-20 = 200), taking into account only the part of the tread intended for walking. In this case, the length of the step will be equal to the radius: 200/2 = 100 cm. In this case, the width of the spiral staircase will be 1/2 less than the thickness of the support beam, but this will not affect the calculations.

The calculation of the width of the upper platform is made by calculating the loss of height when moving along the steps. In the case of our stairs with a 360-degree turn of the march, when climbing one step, the distance to the platform will decrease by 22 cm. Having climbed 5 steps, the height loss will be about 110 cm. If we take into account the thickness of the ceiling (hp = 20 cm), then in there is still more than 2 meters left. Thus, the width of the top platform can be within the width of 5 steps. If it is increased to 6, then the two-meter margin will disappear, and the head of the climber will cling to the upper structures.

To check the calculations, you can use the formula:

H1 = H-5h-hp = 350-110-20 = 220 cm (good result).

By substituting your options into this formula, you can calculate the most suitable sizes.

As you can see, the exact calculation of all the parameters of spiral staircases for the further production of drawings is a laborious task, but simple and interesting. Using the acquired skills or resorting to help, you can easily prepare a quality project and bring it to life.

Spiral staircases are not just building structures, they are an ornament in interior design. They are more compact and more convenient than stairs of other forms. A variety of sizes, designs and materials used allows you to fit such a structure into any interior. And if you spend a little time and effort on studying the design and construction of a spiral staircase, you can independently make such a functional decoration in your home.

Types of spiral staircases

Shaped spiral staircases are polygonal and round. Polygonal ones are installed near the wall, and round structures look more spectacular in the center of the room.

By type of construction, they come with step support:

on the rack;
on the walls located around the perimeter (the walls of the well in which the staircase is formed);
on the fence or bent bowstrings.

If a design with a support post is chosen, then the treads can rest on it or be pinched in it.

Taking into account all the features of the design, it is possible to distinguish four types of spiral staircases:

Simple wedge-shaped steps with a wide end rest on the walls of the stairwell, and with a narrow end on a support pillar, which can be built of bricks or made up of the ends of the steps, on which thickenings are made.
The steps are fixed with a narrow end in the middle monolithic column without support on the walls. This is a very airy design that is not cluttered with details.
The steps are fixed in curved bowstrings with an outer wide edge. In the design of such a ladder there is no supporting column. The construction is very beautiful and unusual and very difficult to manufacture.
A steel spiral staircase with an internal support column, which is made of a thick-walled pipe with a diameter of at least 50 mm, since it is he who bears the main load. Such stairs are the most common and differ for the most part only in decorative elements.

For all types of spiral staircases, there is one feature - they are usually performed without risers, since the steps closer to the support are narrow and the leg, when climbing, stands on them with hanging forward. In general, it is recommended not to walk too fast on the spiral staircase, observing the rules of caution. Reliable handrails are not an element of decor, but a hard necessity, and the dimensions of treads that comply with standard standards are even more important for traffic safety.

The accepted dimensions of spiral staircases are based on ergonomic principles and safety rules, that is, the basis is convenient movement and safe operation of the structure.

Main dimensions:

the width of the flight of stairs 530-1430 mm;
diameter of the hole in the ceiling 1400-3400 mm;
staircase diameter along the outer edge of the railing 1300-3300 mm;
passage diameter along the inner edge of the railing 1200-3200 mm;
the distance between the turns (passage height) is from 1900 mm, higher than a person’s height, so as not to bend down when walking;
the angle of one turn of the staircase in a spiral is 270-360°.
the width of the tread in the movement area is from 200 mm, and at a distance of 150 mm from the rack - from 100 mm, although the optimal width is 280 mm, since when descending, relying only on the heel, you can fall;
step height 150-200 mm. For a spiral staircase, a height of at least 170 mm will be optimal, since when climbing, the upper steps are often above the head of the walker;
the number of steps in a full turn is more than 12, but in the whole structure there should be an odd number of them;
railing height within 900-1200 mm.

If we talk about the main staircase, and not about the attic, then the diameter of the opening in the floor should be not less than 2000 mm, and the tread should be from 900 mm long, that is, the diameter of the stairs is 1800 mm. The 100mm difference per side is meant to make the fence work and the hand rests comfortably on the handrail. For access to the attic, an additional staircase with a diameter of 1200 mm in the opening will be convenient - 1400 mm.

If we take into account that thirty percent of the length of the tread goes to the overhanging of the winders over each other at the central pillar, then a little more than half a meter remains for walking. It is difficult to disperse on such a ladder, but it makes no sense to increase the diameter. In addition, it is difficult to carry loads along it; for this purpose, the diameter of the hole in the ceiling must be at least 2200 mm. But all these shortcomings are compensated by the beauty and compact size of the structure.

Size calculation

In the manufacture metal stairs taken as a support steel pipe with a diameter of 50 mm and a wall thickness of at least 5 mm. Then the narrow part of the tread must be at least 150 mm in order to make a hole for the pipe, so that between the edge of the hole and the edge of the step there is a distance not less than the diameter of the hole. These dimensions are used in further calculations.

Opening dimensions

Legend:

H - opening height;
R is the radius of the circle of the opening;
R1 - the inner radius of the opening or the outer radius of the support column;
r is the radius of the path of movement, usually r = 2/3 R (two thirds of the radius of the circumference of the opening);
γ is the angle of march rotation around the axis in degrees;
n is the number of revolutions of the march around the axis, i.e. n = γ/360°;
L is the full circumference of the opening;
l is the total length of the circle along the line of motion.

The shape of the tread in the spiral staircase resembles a petal, rounded on the narrow side, with a hole in it for mounting on a support post, so we are talking about a console pinched by the narrow end.

Legend:

h – step length, h=R–R 1 (if h is less than 1000 mm, then the cantilever can be made without metal frame only from solid wood);

W 1 - maximum width consoles, chord of a circle with radius R ;

α is the angle between the radii R drawn through the outer edges of the step;

W is the width of the tread, the chord of a circle with a radius of 2/3R;

C - step height;

Z is the console thickness;

N is the total number of steps;

N 1 - the number of steps in one turn.

Calculations of the number of steps and their sizes

According to the formula

L=2πR =2πR,
l=2π* r=2π*2/3 R=4πR/3;

the approximate number of steps in one full turn (coil) can be determined by knowing the average width on the line of motion W ≥ 200 mm

N 1 \u003d l / W \u003d 3 l / 4 πR.

If the standard height of one turn is 1900 mm, then with a margin of 100 mm

C = ((1900+100)+ Z)/ N 1 and N = H / C .

angle α \u003d γ / N, then the width of the console W 1 \u003d R * sin α, and the width of the tread on the line of motion

W \u003d r * sin α \u003d 2 / 3R * sin α.

Having on hand Bradis tables, the width of the tread on the line of motion is easy to calculate. The resulting value should be within 150-200 mm of the required width. If it differs in any direction, you need to change the number of steps and make a clarifying calculation. With such a simple selection, you can set the number of steps for comfortable movement along the spiral staircase.

There is a formula by which you can check the optimal step dimensions: if you add up the width of the tread and twice the height of the step, then the amount should be in the range from 600 to 650 mm (average step size).

When calculating a spiral staircase, it is difficult to follow all the rules, because in addition to safety and convenience, there are also layout, aesthetic aspects, strength characteristics and geometric dimensions of the material from which the structure is made. The most stringent requirements are imposed on the height of the steps. Their width in a spiral staircase is not so important, because it still differs so much along the length of the console that even the steps of the right and left foot of the walker differ in size. Therefore, when determining the optimal value of the step dimensions, they usually choose the option in which it is the height that best meets the standards.

Dimensions of typical spiral staircases

Building a staircase with your own hands is troublesome, calculation of parameters is not so simple, but there are firms specializing in the design and manufacture of spiral staircases according to standard and individual projects from various materials. Manufacturers of mass products offer ready-made standard designs that provide for changing the basic dimensions within certain limits and accessories for them.

The simplest and cheapest design is a spiral one with steps that are fixed on the central post and on the balusters of the screw handrails, and can be designed so that the movement along it occurs counterclockwise and along the way. It is made of metal with various types coverings and wooden steps.

The passport for the product usually indicates standard sizes(the notation may be different, but the essence of this does not change):

ladder diameter D = 2R = 1200, 1400 or 1600 mm;
ladder height in basic configuration H = 2860 mm;
the height to which the structure can be raised by changing the distance between the steps H" = 3090 mm;
height due to additional section H"" = 3320 mm;
distance between steps C = 220 - 238 mm;
step thickness Z = 35 mm;
number of steps N = 16;
the number of steps due to the additional section N "= 17;

and depending on the number of steps and the diameter of the opening different meanings flight rotation angle γ and step length h.

If the angle γ = 450° is specified, then the number of turns of the ladder n = γ /360°= 450/360=1.25.

Explore size calculation algorithm of the whole structure and its steps is worth at least so that, choosing a typical spiral staircase, you can imagine whether it will fit into the existing opening or not, how convenient it is (at least theoretically, you can’t walk along it in every store) and safe, corresponds whether the main parameters of operation of such facilities. And when ordering an individual project, it will be possible to discuss the parameters of future interior decoration with experts almost on an equal footing and with knowledge of the matter.