Anyone with experience of the matter have any idea how to best go about the following?

We recently had some water damage to our ceiling in a few spots, and I cut out the affected pieces (a couple of feet square) and tried putting some new sections in. Problem is that because of the age of the house - and the high heat/humidity of Florida - there's a bit of a natural if slight sag in the ceiling between trusses, so while the new sections are nice and flat, the older ones curve down at the mid point of the joins. Typically I'll try and screw some flat panels of wood between these sections to draw them together, after which I apply gauze tape on the joins and plaster over. But because of the age and curvature on the old ceiling, trying to use this method to flatten them out just doesn't work - the tension in them simply pulls the screws through once I take the pressure off from below - I uses some T-pieces from below to wedge under the ceiling to push it up flat while i try and screw the pieces of wood in place.

The only other thing I can think of is to somehow build up the level of the new sections so that they match the curvature of the old ceiling, then just apply the guaze and plaster on the joins without trying to screw the pieces of wood in place

Any thoughts?

 

Tear it out and re-rock with 5/8" rock.

 

I used to paint in fla and a lot of the builders would cheap out and install 1/2" drywall on the ceilings and then use popcorn to hopefully hide any discrepancies Both the humidity and the blown insulation cause the drywall to sag - that and the 24" centers.

Basically you have 2 choices; tear it out and use 5/8" drywall [best choice but messy and a lot of work] or finish, texture and paint what you have. Once your mind gets occupied with other things, it might not be as bad as you think.

 

I wouldn't be patching it if other options were available. I guess I should have pointed out that we have a sitting tenant in the place, so I can't very well demolish an entire ceiling and raise a dust cloud through the house, especially as there's also an elderly grandmother living in the house who suffers from asthma.

Guess I'll just have to solve it myself and use the method I outlined earlier to build up the patch to match the curvature of the existing ceiling.

@Mark - you're dead right. half inch was standard on older homes throughout Florida, and it's a royal pain in the arse to deal with. We've owned six homes in central Florida, and they all have the problem of sagging between the 2' spaced trusses to one extent or another - it's not that noticeable unless you have sharp angled lighting highlighting the curvature. In our own house, I've replaced a lot of the ceiling for just that reason, using 5/8". Heavy as hell to deal with when you're working on your own and only have some T's to work with, but you learn how to manage.

 

I don't think I'd bother building up the j/c to match the sag, over time it will sag like the rest anyway.