Valleys do the hardest drainage work on the roof.
A roof valley is where two roof planes meet and concentrate runoff. That makes it one of the most important waterproofing details on the roof.
In wooded Woodstock neighborhoods, valleys often collect leaves and pine straw. That debris can hold moisture, wear shingles, redirect water, and hide early leak signs.
Why valley leaks happen
Valleys can leak from worn shingles, bad cuts, nail placement, failed underlayment, storm damage, debris dams, or poor gutter handling at the bottom of the run.
Repair scope
A real valley repair may require opening the valley, replacing damaged underlayment, correcting shingle layout, checking decking, and improving the drainage path into the gutter.
