ᐅ Is the staircase layout in the floor plan acceptable? What does the number 18.3/28 mean?

Oh dear, this sounds like the staircase wasn’t well planned by the architect. We just measured the tread depth in our current apartment, and it’s 28.2cm (11 inches), which feels very comfortable for us. So, the 28cm (11 inches) shown in the floor plan would be good from my point of view. Smaller than that wouldn’t be ideal for us, but we also wear shoe sizes 41 and 43 (EU).

I have also done a bit of reading. Based on the numbers, you can draw conclusions about the steepness of the staircase and how comfortable and safe it is to use.

What do you think? Should I bring this up with the architect again, or is the riser height still acceptable?

Thanks for the information.

Architect: 18.3/28
The floor-to-floor height should be 292.8 cm (115 inches) in your case.

From my profile:
Step measure = 2 × rise + 1 × run – IDEAL: 63 cm (25 inches). For you, this is 2 × 18.3 + 28 = 64.6
Comfort = run – rise – IDEAL: 12 cm (5 inches). For you, this is 28 – 18.3 = 9.7
Safety = run + rise – IDEAL: 46 cm (18 inches). For you, this is 28 + 18.3 = 46.3

To improve the comfort factor, at least one additional rise would need to be added (the staircase will be longer).
Then it would be 17.2/28

Step measure = 2 × rise + 1 × run – IDEAL: 63 cm (25 inches). For you, this is 2 × 17.2 + 28 = 62.4
Comfort = run – rise – IDEAL: 12 cm (5 inches). For you, this is 28 – 17.2 = 10.8
Safety = run + rise – IDEAL: 46 cm (18 inches). For you, this is 28 + 17.2 = 45.2

This would probably be a bit more comfortable, but the staircase would be approximately 28 cm (11 inches) longer.

kbt09 schrieb:
Architect: 18.3/28
The floor-to-floor height for you should be 292.8

From my profile:
Step length = 2 × rise + 1 × run – IDEAL: 63 cm (25 inches), for you that is 2 × 18.3 + 28 = 64.6
Comfort = run – rise – IDEAL: 12 cm (5 inches), for you that is 28 – 18.3 = 9.7
Safety = run + rise – IDEAL: 46 cm (18 inches), for you that is 28 + 18.3 = 46.3

To improve the comfort factor, at least one more rise would need to be added (making the staircase longer).
That would be 17.2/28

Step length = 2 × rise + 1 × run – IDEAL: 63 cm (25 inches), for you that is 2 × 17.2 + 28 = 62.4
Comfort = run – rise – IDEAL: 12 cm (5 inches), for you that is 28 – 17.2 = 10.8
Safety = run + rise – IDEAL: 46 cm (18 inches), for you that is 28 + 17.2 = 45.2

Probably a bit more comfortable, but the staircase will be approximately 28 cm (11 inches) longer.

Huge thanks for the calculation. I was able to follow your reasoning very well. Much appreciated 🙂

According to our architect, adding another step would not be feasible. That discussion took place quite a while ago, and unfortunately I don’t remember the exact reason, but it seemed reasonable at the time. Do you think we can live with the current values? Regarding safety, we are very close to the ideal value. Personally, safety is the most important factor for me when it comes to stairs, even more so than comfort.

The current comfort value of 9.7 cm (4 inches) obviously deviates from the ideal by 2.3 cm (1 inch). However, I really can’t judge if this difference is so significant that every stair climb will be a burden or if 9.7 cm (4 inches) is still acceptable. Do you think we could leave the staircase as it is without regretting it later?

I think so, but try carrying a tape measure with you for a while and "rate" the stairs you are currently using in terms of comfort, etc. Then measure the dimensions each time. Pay special attention to how the tread depth is measured on overlapping steps.

Pädda schrieb:
should I bring this up with the architect again

I’m leaning towards no, but without knowing the staircase layout, it’s hard to judge. For straight stair flights, the dimension certainly seems well chosen.

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11ant schrieb:
I tend to say no, but without knowing the staircase layout, it’s hard to judge. For straight flight stairs, this dimension certainly seems well chosen.

Then I’ll go ahead and post the staircase...