Issue: Corrosion of fasteners used to secure metal ridge vent system on shingle and tile roofs

Concerns raised by the attached letter:

- Severe corrosion was fairly consistent, specifically with the use of electro-galvanized fasteners.

- Similar corrosion problems in fasteners used to secure the new metal ridge backing accessories being utilized with concrete and terra cotta roof tile systems.

- Significantly more serious in coastal environment due to presence of chloride ions.

- Increase in manufacturing of these products outside the United State,

2010 Florida Building Code:

Non-HVHZ

1506.4 Product identification.

Roof-covering materials shall be delivered in packages bearing the manufacturer’s identifying marks and approved testing agency labels required in accordance with Section 1505. Bulk shipments of materials shall be accompanied with the same information issued in the form of a certificate or on a bill of lading by the manufacturer.

1506.5 Nails.

Nails shall be corrosion resistant nails conforming to ASTM F 1667. The corrosion resistance shall meet ASTM A 641, Class 1 or an equal corrosion resistance by coating, electro galvanization, mechanical galvanization, hot dipped galvanization, stainless steel, nonferrous metal and alloys or other suitable corrosion resistant material.

1506.6 Screws.

Wood screws conform to ANSI/ASME B 18.6.1. Screws shall be corrosion resistant by coating, galvanization, stainless steel, nonferrous metal or other suitable corrosion resistant material. The corrosion resistance shall be demonstrated through one of the following methods:

1. Corrosion resistance equivalent to ASTM A 641, Class 1;

2. Corrosion resistance in accordance with TAS114, Appendix E; or

3. Corrosion resistant coating exhibiting not more than 5 percent red rust after 1000 hours exposure in accordance with ASTM B 117.

1506.7 Clips.

Clips shall be corrosion resistant clips. The corrosion resistance shall meet 0.90 ounce per square foot (0.458 kg/m2) measured according to ASTM A 90/A 90M, TAS 114 Appendix E or an equal corrosion resistance coating, electro galvanization, mechanical galvanization, hot dipped galvanization, stainless steel, nonferrous metals and alloys or other suitable corrosion resistant material. Stainless steel clips shall conform to ASTM A167, Type 304.

HVHZ

1517.5 Fasteners.

1517.5.1

Nails shall be minimum 12 gage, annular ring shank nails having not less than 20 rings per inch, heads not less than 3/8 inch (9.5 mm) in diameter; and lengths sufficient to penetrate through the thickness of plywood panel or wood plank decking not less than 3/16 inch (4.8 mm), or to penetrate into a 1 inch (25 mm) or greater thickness of lumber not less than 1 inch. Nails or wood screws shall be hot dipped electro or mechanically galvanized to a thickness sufficient to resist corrosion in compliance with TAS 114, Appendix E, Section 2 (ASTM G 85). All nails shall be listed by a certification agency. All nail cartons or carton labels shall be labeled to note compliance with the corrosion resistance requirements. No roofing material shall be fully or partially adhered directly to a nailable deck, unless otherwise noted in the roof assembly Product Approval.

1517.5.2

Such fasteners shall be applied through “Tin caps” no less than 15/8 inches (41 mm) and not more than 2 inches (51 mm) in diameter and of not less than 32 gage (0.010 inch) sheet metal. “Cap nails” or prefabricated fasteners with integral heads complying with this section shall be an acceptable substitute. All “tin caps,” “cap nails” or prefabricated fasteners with integral heads shall be tested for corrosion resistance in compliance with TAS 114, Appendix E, Section 2 (ASTM G 85), and shall be product control listed. All of cartons or carton labels “tin caps,” “cap nails” or prefabricated fasteners with integral heads shall be labeled to note compliance with the corrosion resistance requirements.