Sent from my iPad
Hi Leah , Clyde and Bobby,
I am writing from Wales UK where we have long experience of building
with lime and also a wet climate. Here traditionally buildings were
built from stone and lime mortar (well into the last century); then
limewash was applied on an annual basis (it's wet here!). The limewash
protects the stone and mortar and over the years builds up into a
beautiful smooth covering. Lime does not hold water, it is the most
permeable commonly (and cheaply) available coating so while it does get
wet it will dry out very quickly. Our old buildings were built without
modern damp proof courses in walls and floors but most of the time if
they are maintained they will stay dry and damp free. However if they
are covered in anything non-permeable, for example cement render, they
will almost certainly become damp: moisture still gets in but it can't
get out. The same applies if latex, acrylic, or oil based paints are
applied, they are not water permeable (at least the ones we have here in
the UK aren't) so they trap moisture which will eventually build up
enough pressure to break through.
I must stress that I am talking about walls, i.e. more or less vertical
surfaces, here so there's no possibility of puddling, and also the walls
are themselves water permeable so they are different to a cementitious
papercrete mix (although I think they would behave very much the same as
a lime based papercrete).
I hope this is at least a little useful!
Simon.
P.S. Someone mentioned lime plaster as an external coating: in the UK it
would be called a lime render and it would definitely not need
reapplying every two years; it should last for centuries!
__._,_.___
