I bought a house with a large drywalled ceiling on an outdoor lanai. While
it doesn't get wet, the drywall tape separates and it's clear from the
patching that this has happened frequently in the past. So I'm exploring
some alternative ceilings and someone suggested putting up lath and stucco.
I have questions about that:

1. Is this at all a good idea, or are there some strong reasons not to do
it? (I haven't investigated cost, but will deal with that as a separate
issue once I know what's viable.)

2. The joists in the ceiling are 24" o.c.. This would be the only holding
point for the wire lath since the drywall won't support weight. So, would
the lath+stucco sag?

3. If sagging would be a problem, I would think it could be solved by
adding a plywood 'underlayment' (? overlayment ?). Do you think that would
be satisfactory and, if so, what thickness plywood?

4. I would think doing ceilings would be highly unusual for most stucco
contractors. So what questions should I ask them to help figure out whether
they'd really be able to handle this?

Thanks in advance for any help or pointers.