I want to know how does one remove or demolish the old ceiling to place a new ceiling.
I put on breathing & eye protection and seal the room to contain dust, A fan in the window with rolled up, damp towels under the door gap very much helps keep dust out of the rest of the building. Also be sure to tape over any forced air registers and return grilles.
Next, I take a razor knife (utility knife) with the blade about 1/2" sticking out and cut where the wall meets the ceiling. Don't try to cut full depth in one slice. Slice a few times. You will use many blades for a whole room.
Next, I deeply score the drywall into manageable squares with my utility knife. Score all the way through. Optionally, one can use a drywall saw or a 14 tooth blade in a reciprocating saw. (Good excuse to buy a new tool if you don't have one)
I'll score and punch a hole in one square near the edge and use it as a handle to yank down the square.
Next, I go back and pull out the ten million nails that stayed behind. Beisange work great because the nails come out easily.
Finally, I sweep, vacuum and damp wipe & mop the work area.
A bit about strapping-
In this part of the country, strapping isn't normally done, it's more of an east coast thing. But I do it.
They go perpendicular to the joists and around the perimeter of the room. The job goes very quickly.
Why Do I Strap?
A) If there is movement from above, such as someone walking upstairs or drywall directly to roof rafters in cathedral ceilings, the strapping helps prevent cracking of joints.
B) With 1 x 3 strapping, you now have 1-1/4" of lumber (half of a 2-1/2" wide piece of lumber) to attach the drywall. Directly to joists will only give you 3/4" to attach. Now you can screw farther from the edge and your cuts can miss a bit
C) You can shim the strapping to have a nice, flat and level ceiling.
D) You can put the strapping on 12" centers if desired. This gives more area that is fastened, preventing sags.
E) Often you end up with fewer joints to tape.
F) If, when you take down the old ceiling, you end up with ragged top edges on the walls the strapping hides 3/4" of it. Add the drywall and you have 1-1/4" of chunks covered. This makes mudding & taping the corners easier.
You can use 1 x 3 wood, as is most often done.
Sometimes, if there is potential movement like a cathedral ceiling to rafters, metal hat channel and fine thread screws can be used. This works great when the rafters move under snow and wind loads.
Many people nail the strapping. I screw it in with 1-1/2" construction (not drywall) screws. For me, screwing is faster than nailing.
