In article , stuart
noble writes

Andrew Gabriel wrote in message ...
Long before portland cement, lime mortar brickwork usually had
some cement in the exterior pointing
I think a small amount of cement is just another pozzolan, but I wonder if
non-hydraulic lime alone has ever been successful externally.

My house is rendered in hydraulic lime and sand, which gives it a
wonderful mushroom colour. We were going to limewash it, but liked the
finish so much we decided to leave it alone.

John
--
John Rouse