Adding a poly layer between old plaster and new drywall???

Hello…
I am at the start of a near-complete bathroom renovation and I have an exterior wall (cellulose insulated) that has the original plaster and lathe on it. As a result of damage to the wall, I would like to drywall over it and have been “advised” to add a vapor barrier over the old plaster first and then drywall in order to ensure the wall becomes more air tight.
I could tear off all the plaster and lathe (and then have to deal with the cellulose in behind) but would rather not deal with the mess…
Should I be concerned with the old plaster (contained behind the new poly barrier) and any moisture issues, barring any leaks or damage to the barrier itself? Or will the old plaster (and lathe) be trouble free contained on the cold side of the barrier??
Any suggestions and/or advise would be greatly appreciated.
Many thanks…RenoKen
PS – Residing in southern Ontario, Canada does offer a wide range of seasonal temperatures which may impact what is done in this case….
Replies
Well, nothing's "trouble
Well, nothing's "trouble free", but having the plaster there shouldn't add to your misery unless there's a liquid water leak into the wall somehow, and then it's just that much more that you have to demo to fix the mess. (Folks are gonna say that it creates a "double vapor barrier", but that's BS.)
There are those who argue that you should never use a plastic vapor barrier anywhere south of the Yukon, but that's a different argument.
Thanks for the input with this issue....
I am going to remove the plaster, poly and then drywall. It will give me the opportunity to take a look at the wall in case there are any other issues.
Cheers...
Plaster
I realize this is an older post, but thought I'd respond anyway.
You do not say when your house was built. If its a vintage home, then restoration is very important and every effort should be made to repair the plaster.. This actually increases the value of an historic house. Demo isn't always the right way to go. However, if the plaster is really bad, then yes, put up drywall.