When I was building the house I had decided to hang all the sheetrock myself and sub-out the taping and texture because that would be just too big of a job to take on by myself.
The house has ten foot ceilings and the time before I had rented a sheet rock hoist it wasn't until I got home and realized it was meant for eight foot ceilings and I had to make piles of pallets with a sheet of plywood on top to reach the front garage ceiling and I tend to drag projects out forever so I try and avoid renting things if I can buy it or make it for the estimated cost of a rental. I've always loved to weld things since I was a teenager so I made a trip to the local salvage yard and got some scrap pipe and tube steel which ended up being about $40 since you pay by the pound. I then went and bought a cable hoist like would be on a boat trailer to put the thing in and out at the dock and 4 heavy casters and pulley with a bracket included for about $50.
Step 1: The Lifting Jack
The basic working component is a two inch pipe about five feet long and a piece of square tube steel, thick walled and I think is about an inch and a half across that fit loosely inside the two inch pipe but not so loose it would just float free since you want it to stay inline as you extend it. By dumb luck the pulley I chose had a bracket spaced wide enough for the square tube to fit through but snug enough to keep the tube aligned so it couldn't spin and get the cable wrapped up and it held the pulley pretty close but not touching the tube.
I never question dumb luck!
Step 2: The Base
I thought hard about the dimensions of the base since I wanted to be able to lift 12 foot sheet without it tipping but also I realized it needed to fit a variety of floor areas so I basically made and X that was about thirty inches wide and about five foot long which allowed me to set it up in hallways and doorways and plus I wanted to be sure this would break down and fit in the bed of a pick up. At the center of the X I welded a piece of two and a half inch pipe that I once again luckily stumbled upon at the salvage yard, about sixteen inches long and welded some braces as seemed fit. I welded the caster to the other side and when you buy the caster the bigger the wheel the easier it is to roll across a floor of a house under construction so you don't come to a sudden stop by rolling across any debris.
Step 3: The Top
For the piece on top to hold the sheet rock as you turn the crank I made a basic rectangle using a lighter piece of tube steel and some angle iron about an eight of an inch thick and probably an inch and a half on the sides. I wanted the top to be fairly light and I had noticed on the one I rented the top had a tendency to let the edges bend down which makes it harder to get flush fits when you're along a wall or putting a second sheet next to the first, so when I laid out the pieces for the top I assembled them upside down and used some half inch wood spacers to make the center form a slight arch and once again just dumb luck that worked out so with a 12 foot sheet of Drywall the sheet remains family close to being in a single plain. You can crank it within and inch of the ceiling joists then make fine adjustments before you turn it the last few clicks on the crank. I also built in some slop so you could teeter totter it in all direction a few degree because every once in a while the floor of a job might not be perfectly parallel to the ceiling.
Another important thing is to sty away from multiples of 12 or sixteen inches when deciding where the braces go in the top part. The reason for this is so you don't every lift and piece up and then discover there is a piece of steel in the way keeping you from screwing the sheet rock up which would mean lowering it and shifting it on the platform.
If you keep your spaces in multiples of 20 inches its very likely at random you will have a piece of steel in your way but you will have plenty of areas not blocked to the point you can get enough screws secured to hold it there long enough to finish screwing it off after the lift is removed.
PS I live in Florida about 30 miles from the Gulf and built this house so I would not need to evacuate during a bad Hurricane so all the walls of the house are covered with plywood glued and nailed every 5 inches to the studs before being sheet rocked and some of the ceilings on the main floor have plywood to. The bottom level of the house has plywood glued and nailed to the ceiling which makes for a very strong roof if the top of the house get's shredded. This makes the bottom level very protected and should be safe in a Tornado since its underground on three sides .
The lift worked great for doing this and let me do that part by myself at my own speed.
Step 4: Odds to End On
Another thing I took into consideration was deciding how high the hoist would be at the lowest setting and I decided to allow for emergencies and made the height six and a half feet. If something happens and the cable breaks and the hoist drops suddenly you want plenty of head room when it stops.
Avoid head injuries at all costs, just trust me on that one.
It actually is easier to manually lift a heavy piece of sheet rock over your head as you place it on the lift than it would be if you had to only lift waste high. Sheet rock is kind of flimsy and if you've ever done this you know the best way is to lift it from underneath than pic up the edges and try and carry it in the same plane as the floor. I'm five foot ten and I was able to do at least a dozen pieces of 12 foot sheet rock up on the ceiling completely solo and on days I had a helper we could knock out a room in no time and my back wasn't killing me any more than it normal does.
I also discovered that using the tape used for putting camper tops to the bed of a truck works to let the pieces of sheetrock slide easier without any gouges a spur on a weld might cause. I just left the plastic backing that you normlly pull off of double sided tape and it held up enough to do about 6000 square feet of ceilings.