Fiber Cement

Not Painted Before but Factory Primed/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

• 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
  
• if efflorescence is present, remove by hand wire brushing; wear eye protection and gloves; if installed and efflorescence is present, try to identify and eliminate any source of water from behind the fiber cement that could have caused the efflorescence
• clean off any dirt, etc. with a detergent and water mixture, rinse thoroughly; or carefully power wash with plain water

b. Priming:

• priming is recommended for maximum resistance to efflorescence and mildew, even though the surface is pre-primed
  
• use quality exterior latex primer that is recommended for masonry or fiber cement
  
• prime immediately after installation; or pre-prime before installation
  
• prime all edges, including where possible those cut as part of installation
  
• 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