snip
If air gets from a hot place to a cold place, then some of the water in it
may condense.
This you really, really don't want happening to books, so they should not
be used as insulation.

What is the construction of the wall?
Plasterboard - gap - stone wall?

Or plastered stone.

The wall is solid brick, plastered on the inside and just painted on the
outside. I suspect the bottom course(s) of bricks might be more solid
(engineering brick?) as a not very successful DPC.

Cheers,

Rich.


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