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?
To add to what others are saying, make sure the base is completely secured. Do not place the base on a rug, mat or anything that could increase the possibility of slipping. Additionally someone wearing shoes with a very good grip should be supporting you while on the ladder, preferably your weight or more.