Rusting: Reddish-brown stains on the paint surface.
Non-galvanized iron nails have begun to rust, causing
bleed-through to the top coat.
Non-galvanized iron nails have not been countersunk and
Galvanized nail heads have begun to rust after sanding or
When painting new exterior construction where
non-galvanized nails have been used, it is advisable to
first countersink the nail heads, then caulk them with a
top quality, water-based all-acrylic or siliconized
acrylic caulk. Each nail head area should be spot primed,
then painted with a quality latex coating. When repainting
exteriors where nail head rusting has occurred, wash off
rust stains, sand the nail heads, then follow the same
surface preparation procedures as for new construction.