Are there any special precautions I should take when painting redwood siding?
  Redwood takes and holds paint better than most woods. It is important, however, to select and correctly apply the right primer.

Use oil- or alkyd-based primers or water-bourne stain-blocking primers on redwood. These primers are available from many paint manufacturers and are formulated especially for redwood, cedar and other wood with a high extractive content.

Follow the manufacturer’s recommendations for application closely. The best finishes will not perform if they are applied incorrectly. High quality acrylic latex top coats provide the best durability.