Peter De Smidt wrote:

Hi, I have some cracked plaster ceilings in the upstairs of my 100 year
old house. Some of these cracks were made worse when the house was
re-roofed recently. The ceilings are 7.5 ft high. I'd like to put
drywall up on the ceiling over the plaster. I'm a little worried about
screwing drywall screws, or perhaps Spax screws, up though the plaster
into the joists, mainly because I'm afraid that plaster dust or small
chunks might keep the drywall from pulling up tightly, or, in a worst
case scenario, the pieces would cause indents in the drywall. I've been
thinking of screwing furring strips to the bottom of the plaster
ceiling, making sure that the screws go into the studs. Then I put rigid
insulation between the furing strips. Finally, I screw the drywall into
the furring strips. Does this sound like a reasonable idea? Any thoughts
and/or suggestions are welcome.


If the plaster is basically still sound with just a few cracks, I'd
repair it (it just goes with the age of the house, primarily and I like
keeping as much original as possible)...

If you're determined, your plan will work if it's basically sound...if
not, it's likely to come down while your doing that (adding the furring
strips) anyway...