My kitchen ceiling joists are old and at varying heights. I'm trying to make it level, or at least flat, in preparation for drywall installation. Would you suggest installing strips of wood to the side of the joists or stacked to the bottom of the joists in order to even them out? Which is easier and faster? Which is stronger?
The way we do it is to strap the joists perpendicular with 1X3 cheap strapping. Find the lowest point in the existing field of joists and that will be your level reference. We use a laser 360 degree level , but you can get by with a good 6 foot standard bubble level. Mark off the joists in 16" on center with an extra piece of strapping along each wall edge. Then set the first piece of strapping closest to the lowest point of the ceiling. Use simple shims under the strapping as you go to keep each piece of strapping level side to side and row or strapping to row of strapping. Secure the strapping with 4d or 6d ring nails to the joists. It will take a little time, but you should get the hang of it very quickly. The result should be a nice flat and level ceiling. I know this is a quick description, but I will be happy to give you more info and hints if you decide to use this method. BTW, this is definitely a 2 or 3 person job, and an air nailer will really help.
Just saw an article on FineHomebuilding about leveling an old ceiling.
It sounds similar to what you ended up doing, except they used steel studs. They also give a good description of the installation process using a couple of guide strings to make sure everything ends up level.
Seems like measuring from the ceiling to the floor wouldn't be much good if the floor isn't level either. We used steel studs which are comprised of two pieces but we just used one piece (half) of the studs and screwed them to the existing joists. We used a 4' bubble level which was okay but I think I'd want to rent a rotary laser level, about $50 per day. The ceiling turned out flat and level but I ran into problems along the two parallel walls when I went to put up crown moulding because I hadn't considered installing a nailer. I ended up removing the drywall, luckily, I hadn't mudded yet, and added the nailer so that I had something to nail my crown to.
Hope the above helps someone.
Just find the lowest joist,use a 8 ft.level,slide across room or 6 ft. level, you should bump into a low joist. If it is only,say 1in. low go to your walls and attach backing.2 persons one on each wall.Each backing about 2 ft long ,but first make level marks on walls with string line,using a small hanging bubbled level that hangs on string line.Now nail all 4 backings ,with are four 2 by 4 blocks to each comer of the room,where the marks are,mark under block.Now fill in space between blocks with straight 2 by 4. When you run sringline be sure the line is the touching the bottom of low joist.2 people to pull string line some tight,2 latters one for each.Use 2 ft.level to square coners, bubble center of lines.Run 3 more string lines, one center of room, other 2 center of center line and lines from first 2 by 4 blocks, total of 5 string lines.No fill in gaps from string line to joist,using plywood strips and thin cardborad strips,each 1 and a have each wide.Now you have a square and level room.It's easy.