ᐅ Combination of landing stairs: straight stair with landing and half-turn staircase

Bauherr8899 schrieb:

I found a staircase design that I find interesting; it kind of combines a landing staircase with a half-turn staircase.

I’m always open to alternative solutions. However, this one doesn’t appeal to me. The steps where a landing could be seem “irregular” in practice, which I consider a safety hazard.

Bauherr8899 schrieb:

What step depths and riser heights do you assume? (Single-family house, 2.5m (8 ft) ceiling height) It’s more of a calculation example, although I don’t really know how to figure it out.

You don’t have to reach the ceiling height but the floor height of the upper story. So, you need the distance from the floor of one level to the floor of the next level.
The DIN 18065 standard describes staircase dimensions.
For riser height, 17 to 19 cm (6.7 to 7.5 inches) is common.
For tread depth, 26 to 30 cm (10.2 to 11.8 inches) is typical.
The ideal slope angle is between 30 and 35 degrees.
An important factor is the step formula (also called “going” or “walk line”), recommended around 63 cm (24.8 inches); it is calculated as riser height × 2 plus tread depth.
Now you have everything to do the calculations.

I will quote @11ant.
"In the example, you can see that the 'landing' has been converted into a uniformly divided four-part spiral. This is problematic for several reasons: secondly, it would be better to use five steps for this. Three would also be an odd number, but with five it works better so that the tread depth (measured along the walking line) harmonizes more evenly with the stride length of the straight steps ‘before’ and ‘after’ the spiral section. And first of all, the transition points between the straight and spiral sections are incorrect here: at positions around 1:30 / 12 / 10:30, the critical points / downward walking direction front edges of the spiral steps align with the toes. It would be better if at these positions the middle part of the tread (i.e., under the ball of the foot) were aligned. The step edges should therefore be shifted downward by half to a full tread depth. The last straight step before the spiral, as seen from above, should also be included in the spiral, as should the first step turning back into the straight section. Your tool is only suitable as a learning example for an apprentice stair builder in their first year to show what would get a failing grade. It could also serve well as a demonstration for an accident insurance training video."

May I assume you are trying to fit within 2.8 meters (9 ft 3 in) including the landing from your DIY plan?
I did some calculations. With a floor-to-floor height of 2.88 meters (9 ft 5 in), you can manage with 18 risers at 27 cm (10.6 inches) even with a landing. The staircase would then fit your 2.8 meters (9 ft 3 in).

hanghaus2023 schrieb:

I quote @11ant.
"You can see in the example that the 'landing' has been converted into a uniformly quartered spiral. This is flawed for several reasons: secondly, it would be better to use five steps for this. Three would also be an odd number, but five works better so that the tread depth (measured along the walking line) aligns more evenly with the stride length of the straight steps 'before' and 'after' the spiral. And firstly, the placement of the transition points between the straight and spiral sections is wrong: at approximately 1:30 / 12 / 10:30 o’clock, there are edges / in the direction of travel downwards—front edges of the spiral steps—at the tip of the foot. It would be better if in these positions the middle tread depths (i.e., those located under the middle of the foot) were aligned. The step edges should therefore be shifted downwards by half to a whole tread depth. The last straight step seen from above before the spiral should be included in the spiral as well as the first step seen from above that bends back into the straight section. Your tool is only good to show a trainee stair builder in their first year what would earn them a failing grade. This simulation could also be used effectively in a safety training video."

Is it safe to assume that you’re trying to manage with 2.8m (9 ft 3 in) including the landing from your DIY plan?
I did some calculations. With a floor-to-floor height of 2.88m (9 ft 5 in), you can manage 18 risers at 27 cm (11 inches) each, even with a landing. The staircase then fits your 2.8 m (9 ft 3 in) measurement.

Thank you. I took away that an additional stair in the spiral section would be better. The reasoning is correct; I was hoping to fit within 2.8 m (9 ft 3 in). I liked the idea of using straight steps instead of spiral steps and gaining extra height over the part that would normally be a landing. I’m not really a fan of a half-turn staircase, so I had other considerations. Unfortunately, the landing staircase takes up too much space for me, so it looks like it will have to be a half-turn staircase if there’s no other option. Thanks everyone.

You have 2.8 meters (9 feet 2 inches) of space. In my opinion, a landing staircase would also fit there.

hanghaus2023 schrieb:

You have 2.8m (9.2 feet) of space. In my opinion, a landing staircase would also fit there.

That’s true, but I think the staircase in the entrance hall shouldn’t open directly onto the corridor, or what do you think? It might feel a bit cramped, so would a half-turn staircase be better? From your experience, what are the optimal external dimensions for a spiral staircase to allow comfortable walking, considering tread width and riser height? (Assuming a floor-to-floor height of 2.88m (9.45 feet)) I know it varies from person to person, but what would be ideal?

In the pinned thread https://www.hausbau-forum.de/threads/grundriss-planung-unbedingt-vor-beitrag-erstellung-lesen.11714/ in this forum section, you can also find images of typical stair layouts.

I do not see a half-landing staircase here. If you plan for a spiral or curved staircase with a depth of about 240-250 cm (94-98 inches), you will be on the safe side.