How to Identify Nailhead Rusting:

Reddish-brown stains on the paint surface.

Possible Cause:


  • Non-galvanized iron nails have begun to rust, causing bleed-through to the top coat.
  • Non-galvanized iron nails have not been countersunk and filled over.
  • Galvanized nailheads have begun to rust after sanding or excessive weathering.


When painting new exterior construction where non-galvanized nails have been used, it is advisable to first countersink the nails then caulk them with a top quality, water-based all-acrylic or siliconized acrylic caulk. Each nailhead area should be spot primed, then painted with a high quality latex coating. When repainting exteriors where nailhead rusting has occurred, wash off rust stains, sand the nailheads, then follow the same surface preparation procedures as for new construction.

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