Fiber Cement

Previously Painted/To Be Painted

a. Surface Preparation:

NOTE‚ If the siding is, or may be, cement asbestos, make no attempt to scrape, sand, wire brush, power wash or otherwise disturb the surface, which could put asbestos fibers into the environment; simply apply a solvent based or latex sealer or primer recommended for exterior masonry surfaces, and once thoroughly dried, proceed with painting

• remove any loose or peeling paint by gentle scraping or with a hand wire brush
  NOTE‚ If lead is suspected in the paint, do not attempt to scrape, sand, power wash, use heat gun, etc., which might put lead into the environment, but rather contact a contractor qualified for lead assessment and abatement
  
• if efflorescence is present, remove by hand wire brushing; wear eye protection and gloves; if possible, identify and eliminate any source of water from behind the fiber cement that could have caused the efflorescence
  
• 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
  
• scrub off dirt, chalk, treated mildew with a detergent and water mixture, rinse thoroughly; or carefully power wash with plain water

b. Priming:

• priming is helpful but not necessary if existing paint is in excellent condition, unless specified by paint manufacturer
  
• prime if there is any sign of efflorescence (remove it first) or any loose paint (remove by wire brushing)
  
• use quality exterior latex primer that is recommended for masonry surfaces
  
• do not leave a primer unpainted

c. Painting:

• use top-of-the-line exterior 100% acrylic latex house paint in flat, satin, or semigloss finish, depending on appearance desired; or a quality latex masonry paint