I live in Indonesia. There is no building code. No insurance. No liability.
Although building codes etc. might say 30cm run, 20cm rise, in practice one can find products such as these, with thousands sold on eBay:
The specs given are similar:
Fixed stair at 57° climb Stair Width - 545mm Stair Width (Inc Handrail) - 572mm Tread Dimensions - Thickness: 27mm Depth: 142mm Width: 491mm
String Dimensions - Thickness: 27mm Depth: 142mm Length: 3340mm
Height 2.835m and 1.745m run
I.e. typically 60cm total width, around 55cm wide for the treads, typically 14cm tread depth and rise of between 20cm and 23cm.
The question is even though we assume these don't meet any building codes, what can we say with regard to the following with regards to such a steep staircase:
- is it a bad idea to have nosing (e.g., you could make deeper stairs but have them overlap by some amount more than what I believe is the maximum of around 1")?
- for some reason the tread depth of 14cm seems fairly common, such that I found stairs with 20cm rise and 23cm+ rise, both with the same depth. Is there any reason this should be so? Logically shorter people might prefer less rise and less depth, whereas taller people might want more depth and bigger rise. However, logically is there any determining factor if one is making such a set of stairs from scratch? E.g. if you have 2.5m total rise, then you could make 12 steps with 20.8cm rise, or 11 steps with 22.7cm. Given 2.1m of total run, the 12 steps would then imply 17.5cm deep treads, and the 11 steps 19.0cm. Obviously none of the options are accessible, compliant, etc., but there should be some way to determine which option is better or worse