STaircase has steps with rise of 19cm and a run of 23cm. If stairs were 28cm..?

Question

A standard interior staircase has steps each with a rise (height) of 19cm and a run (horizontal depth) of 23cm. Research suggest that the stairs would be safer for descent if the run were, instead, 289cm. For a particular staircase of total height 4.57m (457cm), how much farther would the staircase extend into the room at the foot of the stairs if this change in run were made?

Answer 1

Are you sure that a standard interior staircase has that run? I think 23cm run is quite too small.

I've always followed the empiric rule: 2h (height) + r (run) = 62 - 65 cm.

In that case, for a rise of 19cm you should have a run of 27cm.

With 23cm the staircase is uncomfortable and dangerous (a human feet is about 30cm and 19cm is over the "normal" 18cm height).

Generally the suggested dimensions are 18cm height and 27cm run.

For a 29cm run you get 18cm height.

So 457/18 = 25.3 steps.

You can count 26 steps and a height of 457/26 = 17,6 cm.

Or you can count 25 18cm height steps with staircase starting at 7cm from ground (7+18*25=457 cm).

You should also think about two landing (a staircase should have at least 10 steps) with a 80cm lenght.

In that case you'll have 26*29+2*80=914 cm or 25*29+2*80=885 cm staircase.

Bye