A staircase is a complex building structure, which should be distinguished by high reliability, safety, durability, aesthetics and comfort. A concrete staircase corresponds to all of the listed standards. The manufacture of concrete stairs is best entrusted to professionals. During the work, you need to make the right calculations, create a unique project and follow all the steps of the step-by-step instructions.
Such a staircase is often installed in capital or street buildings made of concrete and brick, its service life is more than 50 years, and subsequent cosmetic repairs will update the design and extend its service life to 100 years.
The advantages of concrete stairs
In comparison with a wooden structure, laying a concrete staircase is carried out during the construction of a private house. This is one of the details of the object, enhancing structural strength. Other advantages of the structure include:
- reliability, durability, long service life;
- moisture resistance, minimal risk of fire;
- the possibility of bookmarking with the building, thereby saving;
- the use of corrosion-resistant steel reinforcement;
- the possibility of finishing with any building material;
- resistance to negative external factors, enhanced operation.
Choosing a ladder type
Before the start of construction work, it is necessary to determine the type of construction, the shape of the stairs, and select suitable high-quality building materials. It is not worth saving a lot on the purchase of raw materials, since its quality can greatly affect the reliability and durability of the finished product. The staircase cannot be used immediately after pouring the stairs, as the set of concrete strength lasts up to 4 weeks. Only then can the formwork be removed. You also need to determine in advance the location of the structure, the way the doors are opened.
By design, monolithic stairs are divided into straight (one- and two-flight), spiral (or spiral). Screw versions with running steps have an aesthetic appearance, they are more in demand among consumers, but they require formwork with a radial shape, therefore they are most often custom-made.
An elementary option is a direct interfloor staircase with one march, located between two walls. There will be no end parts of the structure, and the formwork is fastened to the walls. It is more difficult to make a semicircular or monolithic structure based on one wall. To design a free end to the structure, you need to add one side part. You can choose a marching system where there are no supports on the walls (the supporting elements are the lower and upper floors), the formwork is assembled with side elements.
But there is not always enough space to build a single-march version, so preference is given to a two-march version with running steps or platforms between marches.
Also, concrete stairs are monolithic, combined, prefabricated from factory-made marches and typesetting.
The first type is performed on site using the technology of pouring concrete mortar into the formwork; it can be installed anywhere (on the porch, street or basement).
The second option is a complex metal structure (frame) with concrete steps. Each step is cast using formwork and reinforcing mesh, and marble chips and granite crushed stone are used as building materials. The dried surface is polished.
Prefabricated prefabricated marches are mainly used in apartment buildings, however, if you wish and have a small crane, this option can also occur. The main advantage is the price, the disadvantage is the limited standard sizes.
Typesetting types consist of a concrete beam (kosour) and individual steps, which are rectangular, triangular, angular and with a groove. Reinforced concrete types are performed in the factory according to the given sizes and have a standard shape.
Calculation of the stairs
Before starting construction work, you need to measure the space, make a diagram, drawing or project of the planned design with a preliminary calculation of all elements and an indication of the required dimensions. The drawing is developed with a reflection of the design parameters, the number of steps, height and width. As a rule, the height of the steps is 15-18 cm, and the minimum span is 80-90 cm. You also need to take into account the thickness of the finishing material, know the building codes, perform the work in stages, and do not forget about the presence of fences and embedded elements.
Lifting angle
The first parameter is the angle of inclination (rise), the value of which affects the length and height of the structure. So, with an equal height, a product with an angle of inclination of 25 ° will be longer than analogues with indicators of 35 ° and 45 °.
2.35 times less building materials will be spent on the construction of a staircase with an angle of 45 degrees (projection of a span of 3 meters) than for a product with an angle of 25 ° (projection of a span of 6.4 m).
In accordance with the manual, you need to choose the lifting angle based on the suitable sizes of the march, the complexity of the structure and its comfort.
Step sizes
Having decided on the angle of inclination and height, the design work of concrete stairs includes a breakdown into steps. The optimal step size for calculating the width is 27-30 cm, height 16-20 cm. If you make higher steps, then it will be more difficult to move for both the elderly and people who are used to the standard step. Very low steps less than 15 cm will also be inconvenient for an adult, and for children this is the best option.
The parameters of the steps can be selected using the formula: 2H + L = 60-64 cm, where H is the riser (step height), L is the tread (width). For the calculation, you can take the above indicators: 2 * 18 + 30 = 66 cm.
Ladder width
As a rule, the width of the stairs in a country house depends on the free space or the space between the walls where it will be placed. It should not be already 80 cm, because when you climb the second floor along a narrow staircase (or descend from it), a person will feel like in a tunnel. It will also be inconvenient to carry any objects. Therefore, the optimal size will be 90-120 cm.
It is imperative to build a safe and reliable fence, especially when elderly people and children live in the house. If the fence is located on the steps, it will slightly reduce the effective width of the march, keep this in mind when calculating.
Online calculator for calculating
For your convenience, you can make all the calculations using the convenient online staircase calculator.
Formwork assembly
After performing the calculations, you need to independently construct the formwork. The following materials will be required for construction:
- moisture resistant plywood 1.2-1.8 cm thick, edged board from 3 cm thick for the bottom of the formwork, flanging and risers;
- sheets of moisture-proof plywood (0.6-0.9 cm each) for the manufacture of curved zones;
- supporting bars 10x10 cm or boards with a width of 15-17 cm, a thickness of 5 cm for props;
- boards 10x10 cm for mounting boards or plywood sheets;
- metal corners;
- fasteners (wood screws) 3.5 mm;
- concrete, smoothing iron for leveling mortar, grater, device for smoothing the edges of concrete structures.
In order for the concrete surface to remain smooth after solidification, it is necessary to grind the timbering parts of the formwork in contact with the solution. When using smooth plywood, no leveling procedures are required.
The formwork needs to be assembled with the following steps:
- the lower part is made of large boards and plywood sheets. They are tightly fastened together by parallel bars from the outside. The bottom of the structure is supported by bars or boards, while the step of the supports should correspond to the step of the steps. Fix parts with self-tapping screws, which are convenient to unscrew during dismantling;
- flanging from the edged board or plywood on the sides, reinforcing it from the outside with boards;
- mount the rails of the risers to the flanging or the wall with metal corners;
- joints in the details are sealed with a mortar of cement and sand or leveled with a planer, grinder.
The thicker the bars, the higher the structural strength. The weight of the reinforced concrete structure will be large, which must be taken into account during the construction process. Additional stiffness can be given with transverse bars.
Reinforcement
For a small staircase in the cottage, the reinforcement can be made with a grid, which is connected from reinforcement with a size of 1-1.2 cm at a distance of 15-20 cm (the mesh size will be 15x20 cm). The rods are connected by wire.
Large items need to be made of a reinforcing cage, including several grids mounted with vertical rods or welding. The distance between the grids is 2-3 cm.
The frame is the skeleton of the structure where the frozen concrete mortar will be fixed, so its horizontal rods need to be fixed in the wall, in pre-drilled holes. The mesh or frame is laid in the lower area of the formwork 2-3 centimeters from the bottom (you can raise the armature with supports, bricks or stones). In the area of the railing, you need to put corks or metal plates.
Pouring concrete
During concreting, a concrete grade of at least M200 (from class B15) is used. The solution is mixed in a concrete mixer or ordered in RBU, it must contain the following components: 10 parts of cement, 30 parts of crushed stone fractions of 10-20 mm, 20 parts of sand and 7 parts of water. If the composition is dense, then you can add 3 parts of water.
Now you need to correctly fill the composition:
- the lower steps are performed first;
- the solution is rammed to give strength and density. To do this, you can use the reinforcement, which pierce the concrete in several areas. professionals recommend using a more reliable method - a construction vibrator that squeezes concrete through the formwork;
- giving the correct form to the steps, smoothing with a trowel;
- pouring the remaining elements and porch;
- coating the solution with a film to protect against cracks and early hardening. You can also regularly moisten the outer surface of the flooded area with water.
Formwork removal
Concrete gains strength within 4 weeks. After 7 days, you need to remove the boards from the steps and sides. Released surfaces are leveled with a grinder or grinder with a circle for concrete treatment. After 21 days, the retaining bars with the lower area of the structure are removed. And only on day 28 you can completely remove the rest of the formwork.
Finish cladding
A self-made concrete staircase can have different finishes: from wood, laminate, tile, carpet, acrylic stone or porcelain stoneware. Laying of any material should be carried out on an even foundation. After dismantling the formwork, unevenness may remain on the site, which is recommended to be removed by grinding and plastering. The end parts are usually finished with plaster mortar and covered with paint. After this, the steps are covered with one of the materials.
Facing the surface can be done with tiles, artificial or natural stone with a rough surface. The material is laid on cement mortar or tile adhesive. The mosaic is laid using the same technology, making original compositions from small elements.
The finish can be done with abrasion resistant wood panels. For this, larch and exotic species that have undergone antiseptic treatment are selected.
An excellent processing option is a laminate, which is abrasion resistant, easy to lay and durable.
If the house is inhabited by children or elderly people, then you can choose a carpet, available in different colors.
To save steps, you can simply paint with high-quality concrete paint.
In any case, the appearance of the stairs is associated with the taste preferences and financial capabilities of the owner.