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FAQ's > Stucco over painted
brick
Q: Can stucco (portland cement plaster) be applied directly over
painted brick?
A: This is a common question that
often arises when people are rehabbing or updating older construction.
Plaster is a cost-effective finish, relatively easily installed,
that improves the appearance and creates a water-resistant wall
surface.
A painted surface will not typically absorb water and, as such,
is a substrate to which stucco will not readily bond—at least
not uniformly. There are two basic alternatives to covering a painted
brick surface with a new coating of portland cement plaster.
- Sand blast or water blast to remove the paint in its entirety,
then direct-apply a two coat system. It is essential to have a
surface that is uniformly absorptive to accept the plaster coating.
In addition, it may be beneficial to use a
bonding agent or dash-bond coat with this approach.
- Attach paper-backed lath or install appropriate building paper
between wall and attached metal lath to provide a moisture barrier
and to serve as a bond breaker. Apply traditional three-coat stucco
to metal lath and accessories. In this approach, the idea is to
treat the plaster like a sheathed system, using metal lath to
support the plaster on the substrate, while completely isolating
the plaster layer from the backup with building paper. This prevents
a partial bonding situation, which could set up undesirable stresses
in the plaster and lead to cracking.
 For
more detailed information about plaster, refer to Portland
Cement Plaster/Stucco Manual (EB049).
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