Symptoms: Rust Discoloration
This problem is characterized by rust colored reddish-brown to black stains on the paint surface.
Potential Causes:
- Non-corrosion resistant nails were used instead of galvanized zinc plated or stainless steel nails.
- Steel nails became in contact with the air.
- Steel nails popping from surface.
- Excessive weathering or sanding has worn away galvanized coating on nail heads.
- Tannic acid from moist wood (e.g., oak) has reacted with steel nails creating a black stain.
- If possible, replace steel nails with galvanized or stainless steel nails.
- If rusted nails can't be removed then remove rust by sanding nail heads to bare metal and countersink
- Prime with a stain blocking rust inhibiting primer
- Caulk, fill or patch depressed nail heads and sand smooth.
- Paint with a high quality paint.
