Asphalt Roofing

Summary of changes

Activity on this program started: 1932

Reference period of change - January 2018

Target population - Beginning with reference period of January 2018, the survey of asphalt roofing products is based on the North American Product Classification System, 2017 variant 1.0

Reference period of change - June 2008

As of July 17, 2008, this survey is now voluntary.

Date modified: