The Natural Philosopher wrote:

Because that is what they got cheap.

Well, yeah, I get your meaning, but surely the fibre board was *loads*
cheaper than the asbestos sheet (as well as being easier to work).

What I don't get is the juxtaposition of the two materials, when the use
of fibreboard on one of the walls completely nullifies any benefit the
asbestos might have provided.

--
Grunff