Smoothly poured staircase - from below, the stairs have a flat or twisted curved surface, without voids (as in the case of open steps). The smoothness of the lower surface of the stairs is achieved by precise fitting of formwork plywood sheets-segments. The stairs are very strong, but heavy.
 
Bowstring staircase - the side part of the stairs is a reinforced concrete stringer beam with a rectangular cross-section, from which the steps emerge. The bowstring is the main supporting element of the stairs. Bowstring stairs can be both smooth lined and with open steps.
 
Open riser - a flight of stairs consists of separate steps (treads) isolated from each other. The steps have the form of equal plates with an average thickness of 80-110 mm, which come out of the bowstring or stringer staircases.
 
Stringer - Straight or bent beam on which the steps lie. There are options with two beams, which are the main load-bearing elements of the stairs. Mainly treads with open steps are placed on the stringer, but you can also lay a smoothly poured march.
 
Tread is the horizontal plane of the step on which the foot steps. The tread width is on average from 250 to 350 mm.
 
Riser - the vertical plane of the step, which sets the height of the step. The height of the step varies from 150 to 200 mm.
 
Straight staircase - on the plan (view from above), the flight of stairs has the shape of an elongated rectangle. The middle line of the staircase is straight.
 
L-shaped staircase - on the plan, the flight of stairs has the shape of the letter " L ". There are options with an intermediate platform or with running steps.
 
U-shaped staircase - in plan the letter " U ". Four options: with one cross-walk platform, with 2 cross-walk platforms, with running steps and combined.
 
Spiral staircase - on the plan is a flight of stairs in the shape of a circle. The middle line of the march is a circle. All steps have the same inner and outer radius. The turn of a spiral staircase can be complete (360 degrees) or incomplete (less than 360 degrees). At the top, the stairs end with a cantilever platform, which can be supported by a spiral staircase going to the next floor.
 
Bent staircase - a flight of stairs bent in plan with an arbitrary curve. All steps do not have a common center of inner and outer radius (as in spiral staircases). They can be both wall-mounted and free-standing staircases.
 
The middle line of the march is an imaginary line passing on straight sections of the march strictly along its middle, and on curved ones - along a line parallel to the inner edge of the march, at a distance equal to half its width.
 
The width of the staircase flight is the length of the steps, that is, the distance from one edge of the step to the other. The useful width of the staircase is the distance between the wall (or the inside of one handrail) and the inside of the other handrail.
 
 
 
Clean floor of the 1st floor is the design level of the top of the facing material of the 1st floor. To calculate any stairs, the clear height between the floors is required. For example, if you have only floor slabs on the 1st and 2nd floors, then the net height of the floor is:

  Gross height (distance from the top of the 1st floor slab to the top of the 2nd floor slab) + (2nd floor screed + 2nd floor floor covering thickness) - (1st floor screed + 1st floor floor covering thickness)