Atlas Class 4 Impact Ratings: What the Laboratory Test Means
Bulletin dated: January 2016 revision
The cited Atlas certification identifies StormMaster Shake and Slate as meeting UL 2218 Class 4 at manufacture. Atlas also states that the laboratory rating is for comparison and does not warrant performance in actual hail conditions
Atlas technical bulletin: Class 4 Impact Resistance for StormMaster Shingles.
What this means for your roof
The cited Atlas certification identifies StormMaster Shake and Slate as meeting UL 2218 Class 4 at manufacture. Atlas also states that the laboratory rating is for comparison and does not warrant performance in actual hail conditions. A Class 4 rating should not be presented as a hail-proof promise.
A useful question for your contractor
Does the exact proposed product have current impact documentation, and what does its warranty exclude?
Ask for the answer to be tied to the actual roof condition and the exact product being installed. Keep the agreed repair or installation detail with your estimate and project photos.
Bulletin dated: January 2016 revision. The date shown identifies the manufacturer document used for this summary.
Read Atlas: Class 4 Impact Resistance for StormMaster Shingles
This homeowner summary explains the cited bulletin. The complete manufacturer document and current product instructions govern the installation details. A requirement for one manufacturer or product should not be transferred to another without checking.