450lbs but because it is not straight up but up and back that probably gives a 2-1 leverage so 225lb or 100kg. using your legs to lift it would be in the realm of a regular male weight trainer but not the average jo or jane.
Your 2-1 leverage assumption is wrong. The first 1' is full door weight plus all the friction in the system. The effective weight will decrease as the panels transition to horizontal, but deadlifting 400 lbs is easier than overhead pressing 200 lbs.
Sure it gets progressively easier as more and more of the door rides horizontally on its rails. But those first few inches where the door is nearly entirely vertical, must be some significant fraction of the total weight, probably >90%.
Not to mention you have to get your fingers or something underneath the closed door in order to begin lifting it in the first place. So the "from the ground" part is not insignificant.
