Elements of the ladder.
Classification of the types of ladders to be installed provides for their separation according to the main purpose, the intended construction and the material for manufacturing. They can also be located both in the middle of the room and outside the house, and in order to choose the best option for yourself, you need to know the properties of the material for making the frame of the ladder and the principle of construction. The material is usually a tree, metal or brick, as well as derived components of these elements( for example: reinforced concrete).By purpose and functional application, the following types of stairs are distinguished: 
- input;
- installed between floors;
- portable and stairs - "transformers";
- rotary stairs, with several marches;
- special and landscape.
From a wide variety of types of stairs, consider those that are installed in the middle of the house, between the floors, and the material for the construction of the skeleton of this design is a profile pipe. Consider the obvious advantages:
- metal frame provides a staircase with high strength;
- design can have any form;
- for the installation of the frame will take very little time;
- metal is not so affected by external factors as wood;
- is simple and quick to manufacture elements of the whole design;
- the possibility of ordering stairs of any configuration and color, which harmoniously fits into the interior of your house;
- low cost;
Drawing a ladder from a profile pipe will help you to orient in the amount of the required profile and the estimated installation costs.
The interstore ladder inside the room can be made with march flights, on bolts or screw. Whichever option you choose, the main element of any staircase is the steps and supports on which they hold. A part that supports the steps only from below is called a Kosower, if there are three such elements, then the middle Kosower will be intermediate. If the supports are located at the side and bottom of the step simultaneously, closing its end, such an element of the ladder is called the bowstring. 
Each step on the stairs has its own tread and riser. The horizontally located part, on which they come, is called a tear, and perpendicular to it is the sub-step. Some stairs do not have this element. 
Screw ladder made of metal profile is mounted on bolts fixed in the wall and holding one end of the step( bolts) and the posts to be installed for support from the other end. Elements that enter the frame of the ladder from the profile pipe have a stand, a bow and a kosur, and on this structure steps are constructed of any suitable material.
Installation of ladder from metal profile.
In the drawing of the ladder from the profile pipe, you need to specify the dimensions of the staircase and the height of the floor, to start the installation of the frame. After this, a specification is compiled, in which a complete calculation of the number of stages is given, based on their dimensions, as well as the shape of the supports and their magnitude. Calculate the design of the ladder in such a way that the person would be comfortable walking along it, not bending down, and with a sufficient width of the step.
- When installing a spiral staircase on the framework of the profile pipe, the narrow end is fastened to the steps, and its wide part is fixed to the wall by the masters or on a spiral stratum.
- Welding is used for the installation of the flight ladder from the profile. For the manufacture of kosurov use a pipe, which is welded to the steps.
And finally - for easy movement on the stairs, consider the possibility of installing a handrail.