Stucco

Old and Unpainted/To Be Stained

a. Surface Preparation:

• if efflorescence is present, remove by hand wire brushing; wear eye protection and gloves; try to identify and eliminate any source of water from behind the stucco that could have caused the efflorescence
  
• scrape out and widen any cracks; brush out dust, and seal with 100% acrylic or siliconized acrylic caulk; make second application in several hours if needed; wall and chimney caps must be sound and continuous; chimney flue should have rain cover
  
• treat any mildew with a 3:1 water:household bleach mixture, leaving it on for 20 minutes and adding more as it dries; wear eye and skin protection; rinse thoroughly
  
• remove dirt, chalk, dust, unbound sand, treated mildew, etc. by scrubbing with detergent and water, and rinse thoroughly; or power wash with plain water, taking care to not drive water into cracks or porous areas

b. Priming:

• be sure any sources of moisture behind the substrate are eliminated
  
• priming is not essential with quality exterior latex solid color stain but priming will maximize sheen uniformity and minimize efflorescence and mildew
  
• use quality exterior latex primer that is recommended for masonry surfaces
  
• do not leave a primer unstained

c. Staining:

• use top quality exterior 100% acrylic solid color stain that is recommended for masonry or stucco surfaces
  
• some solvent based acrylic masonry or concrete stains may be applied to stucco without priming… consult manufacturer’s directions