Summary for electrogalvanized nails Discussion
Electrogalvanized nails for 3 tab shingles are identified as the likely cause of the roof failure described by James Covington, who reported widespread rusting and leaks beginning a little after two years and worsening by four years, especially on the lower roof elevations where water flow is greatest. Dr. Thomas H. Cook replied that the proper fastener should have been hot dip galvanized nails, which carry a much thicker zinc coating—about 10 to 20 times thicker than electrogalvanized coating. He added that stainless steel nails would likely be even better. The exchange suggests that electrogalvanized nails may not provide enough corrosion resistance for this roofing application, particularly in wetter, more exposed areas of the roof.
Q. I have had catastrophic results from using this type of nail for a typical 3 tab fiberglass shingle roof, 4:12 slope. Complete failure starting at a little after two years from installation and is wide spread after 4 years. Nail heads are rusting off and allowing water to leak through the voids that are left. Problem starts at the lower elevations of the roof where the sheet flow of water is the greatest. Does not seem to be a problem in the rows nearest the peak of the roof.
I am wondering if anyone else is having this type of leak problem after using this type of nail for this purpose? Should I have not used this type of roofing nail in this application?
James Covington
Home owner – Altamonte Springs, FL, USA
February 8, 2010
February 9, 2010
A. Sir:
What you should have used is HOT DIP GALVANIZED NAILS, which have a MUCH THICKER ZINC COATING (10 to 20 times thicker zinc). In the alternative stainless steel nails would likely be even better.
Regards,
Dr. Thomas H. Cook
Galvanizing Consultant – Hot Springs, South Dakota, USA