Central stringer beam staircase is very difficult type for designing and for building as well. The staircase which is most suitable to be constructed with concrete is also durable, strong, pleasing and functional. This type of staircase can be designed in grater widths, longer spans and in any height.  
This staircase type appearance can be changed in covering it with tiles, terrazzo, slabs of stones, marble tiles… The link bellow will give you already calculated designs you can use right away. 
Download here.

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