I installed it 20 years ago so I can’t remember
Looks like it weighs 59 lbs. I would say that either I followed the instructions OR I might have used a temporary brace or clamp to hold it.
I have the same kind. Didn't install it myself, but I did install one at my folks house years. One guy in the attic, one guy below. No big problems. Do shim and BOLT the frame in place. Don't use screws. The weight of the ladder, plus you, plus whatever you're carrying, adds up pretty quickly. No reason to cut corners when installing it.
The 12 ft ceiling height does warrant thought. Gotta make sure you have the right model.
Also, they install between the bottom chords of the trusses. Keep this orientation in mind, when locating the ladder. You don't want to have to move vehicles every time you want to pull the ladder down.
Regarding how hard they are to open, it shouldn't be an issue. I have to pull down pretty hard on mine to get it to open. Even yesterday, I didn't notice it pounding with air pressure.
And I did lose a couple sections of fence yesterday, so that was a pretty good blow.
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Just set a little bit of weight on it. Don't do what I did...middle of summer mine does the banging in a thunderstorm. I look around the garage to see what is heavy and something I don't use. I see a six pack of some god awful shasta pop. Set that up on the sheetrock cover. Alls good until Early December. It looks like brown snot dripping off the cover...never crossed my mind that it would freeze up there.
Ouch. That would not have occurred to me either.