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Comment on Dumb question: Is it safe to use extension ladder on interrior wall?

If you lean a ladder against a wall, only a small part of your weight pushes against the wall horizontally, most weight is still directed towards the ground. You can roughly estimate how much of your weight will push against the wall:
with a vertical ladder it would be 0.
with a ladder put up in a 45 degree angle it would be 50%.
Your angle will be somewhere in between.

My guess is any wall can handle this, otherwise it would fall if you lean on it. But no one can tell you for sure without inspecting it.

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AFKBRBChocolate@lemmy.world ⁨11⁩ ⁨months⁩ ago
Right, this is the correct answer. Even with a very tall ladder, the force is relatively small. If the ladder is well anchored, you can demonstrate this by standing at the top, holding on tightly, and pushing on the wall to see how hard you have to push to move the top of the ladder away from the wall a little.

Also worth mentioning that they sell covers/pads for the top of the ladders to prevent denting the drywall, but you can also make them from a piece of foam pool noodle.

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- KISSmyOS@lemmy.world ⁨11⁩ ⁨months⁩ ago
  
  you can demonstrate this by standing at the top, holding on tightly, and pushing on the wall to see how hard you have to push to move the top of the ladder away from the wall a little.
  
  Yeah, I’m gonna go ahead and just not do that.
  
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  - AFKBRBChocolate@lemmy.world ⁨11⁩ ⁨months⁩ ago
    Heh, fair enough, though if that’s enough to make you feel backwards, you don’t have enough angle on your ladder.
    
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Pickle_Jr@lemmy.dbzer0.com ⁨11⁩ ⁨months⁩ ago
Ah interesting point about the weight distribution. I agree then; I should be fine!

Just wanted to make sure I wasn’t missing anything I should be considering.

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- A_Union_of_Kobolds@lemmy.world ⁨11⁩ ⁨months⁩ ago
  Make sure to follow the 4-to-1 rule - for every 4’ of climb, the base should be 1’ from the wall.
  
  You should be fine. Ideally, you’d tie the ladder off to something, or have the top extend 3’ above the surface it’s against (like if you’re using it to get to a roof). Obviously neither of those really apply here. I’m an electrician and we have to do stuff like this pretty often.
  
  As for the strength of the wall around the windows, those should be framed in, meaning there are extra 2x4s around them. Try to extend the ladder higher than you need to be so you’re not on the very top of it and you’ll be alright
  
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intensely_human@lemm.ee ⁨11⁩ ⁨months⁩ ago
I have a major in structural engineering, and I’m commenting to say that you want to be very careful with reasoning that something will total less force because it caps out at your body weight.

Just to give an example, if you have a wire strung between two poles, and you hang your 100 lb self from the middle of that wire, the tension against the poles can easily be thousands of pounds.

It’s not going to play out that way with the ladder, unless the ladder is flexing. But if you have a ladder that bends, and it’s got a 10 degree bend in it, while the ladder is straightening it can be exerting far more force than your weight on the two ends.

Considering the static force diagram, a 100 lb downward force is going to be balanced by a set of opposing forces that sum to an upward 100 lb force.

Given that there are horizontal forces involved too, these individual force components can easily be greater than their sum.

Not saying for sure this ladder situation is one of those situations, but if you’re consistently applying a heuristic that a system of forces will be limited to the force input of an external stressor, you can be very rudely surprised by the actual system when it generates forces in the tons.

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