International Residential Code

SUBJECT: Attachment of Asphalt Shingles
CHANGE TYPE: Addition

R905.2.6 Attachment. Asphalt shingles shall have the minimum number of fasteners required by the manufacturer. For normal application, asphalt shingles shall be secured to the roof with not less than four fasteners per strip shingle or two fasteners per individual shingle. Where the roof slope exceeds 20 units vertical in 12 units horizontal (167% slope), special methods of fastening are required. For roofs located where the basic wind speed per Figure 301.2(4) is 110 mph (49 m/s) or higher, special methods of fastening are required. Special fastening methods shall be tested in accordance with ASTM D 3161, modified to use a wind speed of 110 mph (177 km/h). Class F. Asphalt shingle wrappers shall bear a label indicating compliance with ASTM D 3161 Class F.

Shingles classified using ASTM D 3161 are acceptable for use in wind zones less than 110 mph (49 m/s). Shingles classified using ASTM D 3161 Class F are acceptable for use in all cases where special fastening is required.

CHANGE SIGNIFICANCE:There were no requirements in the 2003 code for labeling of shingle wrappers containing shingles that are intended for use in high-wind areas. In regions with basic wind speeds of 110 miles per hour or greater, building officials, consumers, roofers and suppliers had difficulty verifying that shingle products being used were in fact approved for special fastening methods in accordance with ASTM D3161, Class F. The language in the 2006 code requires that all such shingle wrappers be labeled to indicate special fastening methods in accordance with ASTM D3161, Class F. This eliminates confusion and misapplication of shingles in high-wind regions. The last paragraph, which provided clarification about where shingles tested to ASTM D3161 could be used, was relocated without any technical changes to Section R905.2.4.1.