One reason could be that they are better fixed in ground than in walls. Was this the only reason?

  • 2
    I am a bit curious about what prompted you to ask this question. I guess you are only talking about the context of imprisonment and not the use of bars for household security purposes?
    – Michael Lai
    Jul 23, 2014 at 4:54
  • 1
    This question appears to be off-topic because it is about the history of imprisonment. I fail to see the User Experience aspect of jail bar alignment. Jul 23, 2014 at 5:13
  • @BennySkogberg aren't many UX.SE questions of the form why does something is the way it is? What's so different then about my question?
    – user13107
    Jul 23, 2014 at 5:15
  • @MichaelLai bars for household security? I don't get what you mean by that.
    – user13107
    Jul 23, 2014 at 5:16
  • 1
    Other questions are at least related to UX, usch as ux.stackexchange.com/questions/52336/…. But I can't see that on Jail Bars, I'm afraid. Jul 23, 2014 at 5:18

3 Answers 3

  1. Floors and ceilings are stronger than walls
  2. One can climb horizontal bars as one would a ladder
  3. One can use the body's strongest muscles to apply force to the bars

Regarding @SNag's quote from Quora- Namit Kothari must not be a welder. Usually in steel the weld is the strongest part of the structure.

I'll give you one more reason that hasn't been mentioned - it's easier to put a door into a vertical bar setup, since the vertical bars wouldn't require an additional frame to support the door.


This is kind of user experience, so...

  • This is a wild guess, but if they were horizontal, prisoners can use the added support of gravity to bend them.
  • They fit better in the ground.
  • Usually the distance from ground to ceiling is shorter than the distance between side walls. More the distance, easier it is to bend a bar.
  • Prisoners can use horizontal bars to hang themselves.
  • Horizontal bars are easy to climb.
  • If you have horizontal bars, you need a column in the middle to attach a door, if not the door is one of those weird cat-flap things.
  • 1
    Can't vertical bars also be used to hang themselves? It is just how you tie the knot.
    – Michael Lai
    Jul 23, 2014 at 4:53
  • 1
    @MichaelLai: But knots will often slide down in vertical bars. Not all of the prisoners were boy-scouts. Jul 23, 2014 at 4:55

This question was recently asked and answered on Quora. For the benefit of the non-Quora user, I reproduce the top answers and comments here:

I believe the answer lies in Newton's third law of motion. The bars are made thick to prevent a prisoner to break out free.

Case 1 : Assume the bars are horizontal. In this case, the prisoner has a better chance to bend the bars as the ground gives the desired 'normal reaction' to the prisoner against the force applied by the prisoner to bend the bars. This makes it easy to achieve the result.

Case 2 : Assume the bars are vertical. The force required by the arms (way weaker than thighs) is same but the arms require better leverage than thighs to bend the bars which makes it way more difficult to break free.

(Source: Namit Kothari's answer to Why are jail bars vertical and not horizontal?)

There are two reasons for this - strength and cost - both of which are related to the welding.

The weakest point of a metal structure is the weld holding it together. A vertical door (ie one longer in height than width) will have less individual bars (and less weak points) than a horizonal one if the bars are the same thickness. Therefore it is a stronger door, which is its main purpose.

The other factor is that a weld must be applied by a welder, which takes time and effort. Less welds equal less time, which is generally cheaper.

(Source: Tom LeGrice's comment on Namit Kothari's answer)

...there might also be a psychological or affordance-based reason, namely that the horizontal bars would allow the prisoner to look from side to side over the horizon and have sense of "free range" from that. The vertical bars will obstruct this visual sense of freedom and "clip" the visual space into smaller bits. I am guessing that could be an "effect" subconsciously wanted by the imprisoner.

(Source: Martin Kofod Ludvigsen's answer to Why are jail bars vertical and not horizontal?)

See all answers here QUORA: Why are jail bars vertical and not horizontal?

  • 1
    problems with these reasons is that without references, they could be thought of afterwards rather than before design.
    – user13107
    Jul 23, 2014 at 5:22
  • @user13107: I agree, but sometimes it's hard to find references for these kind of questions and most reasoning seems retrospective. Check this similar question.
    – SNag
    Jul 23, 2014 at 5:49

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