Question and answers on Stucco and Plastering-- July, 2013
stucco on adobe blocks
I have been asked about bonding
cement mortar to adobe (dried clay) blocks.
I haven't ever worked with adobe, but I have heard this from
people from Central America,
where adobe is still used a lot. Don't laugh at adobe. Adobe
is almost earthquake proof, has
excellent thermal mass, and is as earth friendly as a building
material can be.
Adobe is essential is restoring historic buildings in the
Southwest and other places.
Here's the mystic secret:
Before stucco application the adobe blocks are splashed with
lime, that is a soupy
mix of lime and water. The lime soaks into the surface and
hardens the surface.
After the lime dries, it is real porous creating good suction
for a bond with cement mortar.
I haven't ever done this, but it seems real credible to me.
Also, I heard about the lime
trick from reliable sources.