External coatings on historic buildings

Orit Soffer <oritsoffer [at] justemail__net> writes

>I am having doubts regarding the correct way of applying lime-based
>coatings on historic buildings, so that the coating would resist for
>a reasonable number of years in environmental conditions which
>consist of pollution, sea air and a warm climate (no frost
>problems). ...

Since  (theoretically) I'm on holiday in Italy, I have to be brief;
as an architect and architectural restorer I have a pretty good
experience with this kind of problem.

If you want to do it the classical way first have a rough first
coating of lime plaster with a clean filler of rough sand, then a
finer coat of finer sand plus lime paster scratched in order to
receive the final coat of finer sand/lime (if you want added with
puzzolane or crushed bricks  plus the pigments. You could also add
powdered marble (of different shades) to obtain a smoother finish
coat.

Be careful the mixture will dry as a two to four shades clearer than
the wet color. You could add some polyvinyl alcohol to the mixture
but usually that's not necessary.

Careful when when applying the final coat because it will retain all
the strokes and brush stokes of your applying. The final color will
not be uniform, but the well desired mottled finishing of the
fresco.

If you need more information I'll be at home (pierlucio [at] istop__com)
after July 5, 2003. Good luck,

Pierlucio Pellissier in Montreal (actually on holiday in Aosta
Valley)


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                  Conservation DistList Instance 17:4
                   Distributed: Monday, June 23, 2003
                        Message Id: cdl-17-4-008
                                  ***