The message
from "Mark" contains these words:

When PB came out it had a coarser surface than todays and was nailed in
place then all the joints covered with strips of 2" or so wide wood. I
saw a place done like this once, it looked terrible. Whatever possessed
them to do it like that? I thought it dated back to the 30s, but not
sure.

LOL
That was not plasterboard, it was white asbestos sheets quite common in
early 30s houses.
I can even supply a picture of a ceiling still like that.

One of my rooms has a ceiling like that although the board in question
is neither plaster nor asbestos but fibre.

--
Roger Chapman