"tree" wrote in message
.. .
I've been tasked with fitting some bookcases into a room in our new house.
In order to make the most of the available space, it has been decreed that
they are to be built in.


Have a ventilated gap and some foam, in which case should the foam be
inside
or outside the air gap?

Insert plastic sheeting anywhere into the above schemes?


If you have the space :
Wall - 10-20mm gap - 20mm KIngspan/Celotex - 10mm gap - plastic pinned to
closed back of bookcase

If the gap between the wall and Kingspan gets wet it is damp from the wall.
If the gap between the Kingspan and the plastic gets damp it is condensation
from the room.

Don't use polystyrene - the books are probably enough of a fire hazard
without adding to it.