Cinder Block

Old & Unpainted /To Be Painted/With Elastomeric

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 block 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; check mortar joints carefully and repair or re-point as 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 mortar joints

b. Priming:

• priming is not essential with quality exterior 100% acrylic elastomeric wall coating, but will aid efflorescence resistance, and maximize adhesion of the elastomeric
  
• use quality exterior latex primer that is recommended for masonry surfaces
  
• do not leave a primer unpainted

c. Painting:

• use top quality exterior 100% acrylic elastomeric wall coating
  
• apply two coats for maximum crack bridging and durability
  
• apply at manufacturer’s recommended spread rate; for best performance, this will be 40 - 60 sq.ft./gallon to achieve a minimum dry film thickness of 7 mils per coat.

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