A.Ron Webber, owner of
Prime Plastering in Irvine, Calif., responds:
Applying new stucco over old stucco (often called
re-stuccoing) is a fairly simple-process. If the
existing wall is in good condition, this job can be
straightforward. But if the existing surface has
imperfections, the problems that caused the flaws
must be repaired, or else the problems will recur.
Before re-stuccoing, thoroughly examine the
existing surface and ask the following
Is there any loose, spalling
stucco? Rub and tap the wall,
listening for hollow sounds. Any loose stucco will
need to be removed by scraping or sandblasting. To
patch the stucco, combine sand and cement with
calcium aluminate, an accelerator, or use a good
nonshrinking stucco patching material or a
rapid-set mortar mix.
If the house has been painted, is
the paint in good condition? Loose or
chipping paint can reduce the bonding power of a
new coat of stucco, so it should be removed by
sandblasting. If the painted surface is in very
good condition, you can apply stucco directly over
it, as long as you use a bonder.
efflorescence? Efflorescence is a
white powder or film on a surface, composed of salt
crystals left behind when salt-laden water
evaporates. Efflorescence reduces the bonding power
of the new coat of stucco. To neutralize
efflorescence, spray on a mild acid such as
vinegar. Let the vinegar sit for half an hour, and
then flush the wall with water. This will bring the
pH level down to an acceptable level.
Is the wall dirty?
Dirt, like loose paint or efflorescence, will
interfere with the bond of the new stucco. Any dirt
should be washed off.
Does the wall have any cracks or
leaks? Leaks near doors and windows,
as well as cracks, should be repaired before
re-stuccoing (see "Patching Stucco," 9/97).
Is the flashing in good
condition? Inspect the metal flashing
and weep screed for rust or separation at the
joints, and repair or replace it as necessary.
Is the existing stucco surface rough
and uneven? If so, scrape down the
high points and fill in the low areas before
Once all problems in the existing stucco have
been corrected (including, if necessary, adding a
leveling coat to even out the low areas), apply a
new finish coat with the texture and integral color
of your choice. To ensure a good bond, use a bonder
between the existing stucco and the new