Title is pretty much everything!
I have these high up windows that I'd like to clean and maybe in the future install curtains on. I guestimate the wall being 20ft (6m) tall.
For other rooms in the house I typically use an A-Frame, but it's impossible to find an A-Frame to reach that high where I am.
I plan on draping a towel over the top of the ladder to prevent scratches and scuffs on the wall, as well as getting a rubber mat or something if the floor seems slippery. I am just not sure if drywall would support a ladder? Especially near the frame of the windows. Maybe there's something else I'm not considering as well?
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% (actually less).
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.
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.
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.
Yeah, I'm gonna go ahead and just not do that.
Heh, fair enough, though if that's enough to make you feel backwards, you don't have enough angle on your ladder.
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.