A California valley is a closed valley method where shingles are run through the valley from one roof plane and a second shingle course is installed along the adjoining plane.
Why It Matters
Valleys move a lot of water. The installation method affects drainage, appearance, durability, and whether the roof follows the shingle manufacturer’s requirements.
Common Problems
Common issues include using the wrong valley method for the roof design, poor nail placement, uneven shingle alignment, and relying on a valley style that the product manufacturer does not approve.
Building Codes & Industry Standards
California valleys should only be used when allowed by the roofing manufacturer and installed with the required underlayment, fastening, slope, and water-shedding details.
Exterior Echelon Notes
Exterior Echelon reviews valley style as part of roof replacement planning because valleys are one of the most important leak-prevention areas on the roof.
