Atlas Open Valleys: Keep the Water Channel and Fasteners Separate
Bulletin dated: June 2017 revision
Atlas’s open-valley detail uses sheet-metal lining and a channel that widens toward the eave. It specifies shingle overlap, corner trimming and cementing along the lining, with no exposed nails in the valley flashing
Atlas technical bulletin: Valley - How to Install an Open Valley.
What this means for your roof
Atlas’s open-valley detail uses sheet-metal lining and a channel that widens toward the eave. It specifies shingle overlap, corner trimming and cementing along the lining, with no exposed nails in the valley flashing. These details help direct concentrated runoff without leaving fastener holes in the drainage path.
A useful question for your contractor
Will the finished valley preserve the required channel width and keep fasteners out of the exposed flashing?
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: June 2017 revision. The date shown identifies the manufacturer document used for this summary.
Read Atlas: Valley - How to Install an Open 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.
Discuss your roof with Barnes N’ Roofs
Cover image: Atlas, from the linked manufacturer bulletin. Read the complete source for the full detail and its limitations.