Aluminum Siding

Bare Metal is Exposed/To Be Painted

a. Surface Preparation:

• 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 there is any white oxide on bare metal, remove as much as possible by rubbing with non-metallic scouring pad (note: if steel wool is used, residual particles, if not completely removed, can eat pin holes through the aluminum)
  
• remove dirt, chalk, treated mildew, etc. by scrubbing with detergent and water, and rinse thoroughly; or power wash with plain water; chalking on weathered aluminum siding tends to be deep in the factory finish, and a second treatment may be necessary if there is still noticeable chalk on the surface

b. Priming:

• priming of the old factory finish generally is not necessary if chalk can be removed as part of surface preparation
  
• for areas where chalk is stubborn and cannot all be removed, apply a solvent based exterior primer recommended for this substrate
  
• for areas where metal is exposed, remove any white powdery oxide with a non-metallic scouring pad, and apply a latex or oil-based exterior metal primer that is recommended for bare aluminum
  
• do not leave a primer unpainted

c. Painting:

• use top-of-the-line exterior 100% acrylic latex house paint in flat or satin finish, depending on appearance desired
  
• a flat finish will be much less revealing of dents and irregularities in the siding than will a glossier finish
  
• for best results, apply by spray