Atlas California Valleys: Follow the Actual Drainage Detail
Bulletin date: not stated in source
Atlas approves its illustrated California closed-valley method with specified crossing shingles, a vertical row and fastener clearances. The name of the method alone does not describe a complete installation
Atlas technical bulletin: Valley - How to Install a California Valley.
What this means for your roof
Atlas approves its illustrated California closed-valley method with specified crossing shingles, a vertical row and fastener clearances. The name of the method alone does not describe a complete installation. Valley preparation and the exact sequence determine how concentrated runoff is managed.
A useful question for your contractor
Which Atlas valley detail is specified, and how will its fastener clearances be maintained?
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: not stated in source. The date shown identifies the manufacturer document used for this summary.
Read Atlas: Valley - How to Install a California Valley
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.