^If I recall correctly, each bail/single bag weighed 80 lbs. Architect shingles weighed more. I spent many days carrying two bails up the ladder and throwing them on the roof. When I started, I didn’t know how to roof, so I always had to carry the shingles. Also, I was/am big. So I couldn’t walk on some of the older roofs. Yep. Carrying 160 lbs up a ladder in 100° heat all day, will put some hair on your chest.
We had a 60 ft ladder that was missing pieces. It had a 275 lb weight limit. I weighed about 230 at the time. So. When I carried up two bails at a time, it acted like it was going to break. I had countless nightmares about it.
My old boss was far more concerned about speed than safety. Until he actually fell from a ladder, and broke his pelvis, hip, and ribs. After that, he changed his thinking about safety.