Description:
Color loss and overall
deterioration of paint film on fresh masonry, concrete or stucco.
Possible Cause:
Stucco and mortar joints
contain hydrated or “hot” lime, a dry compound added to improve the
workability of these materials. Different mortars are compounded with
different amounts of “hot” lime, depending on the end use of the mort a r.
This problem is then made worse by more “hot” lime being added at the job
site.
The alkalinity of fresh or new mortar, cement mixes and concrete is
expressed numerically by pH readings. The pH of fresh cementitious materials
is 13 to 14. It takes approximately 30 days for fresh cement materials to
drop to an approximate pH of 9. A pH of 9 is less alkaline than a pH of 13,
and a coating has a greater assurance of success when applied to a less
alkaline surface.
Once these cement walls are cured, the introduction of moisture into these
walls will reactivate the high pH alkalinity, resulting in efflorescence,
blistering and peeling of the paint film.
Solution:
When damp areas are found on
surfaces, the source of moisture intrusion must be repaired. The surface
should be prepared by removing chalk, efflorescence and damaged paint film,
and must be thoroughly dry before applying new paint.
Recommended
System:
Primer
FLEX BON #107 Series Interior Acrylic
Latex Primer
Topcoat
Top Quality FLEX BON Interior
Latex Paint |