Roof valleys occur where two sections of sloped roofs meet. You can see them around dormers and the seam between wings of a house. Valleys are prone to leaks due to water converging in the valley’s trough. How to fix a shingle roof valley requires you to tear out the old material in the valley. To create a continuous shield against water, you will install a sheet metal valley over the entire groove.
Roof Safety Tips
Before starting the steps for how to fix a shingle roof valley, educate yourself about roof safety. Falling off your roof will cause considerable injury. You should follow these best practices to reduce your chance of falling.
When working on a roof:
- Where non-skid shoes
- Use a fall-arrest harness, especially on steep roofs
- Work in dry weather
- Avoid days with high winds
How to Fix a Shingle Roof Valley Step by Step
- Sweep dirt and debris out of the roof valley.
- Measure and mark lines with a chalk line 8 inches on each side of the central V of the valley.
- Go to the top of the valley and start cutting the shingles on the line.
- Use a pry bar as needed to lift off shingles and remove nails.
- Working your way downward, take off 8 inches of shingles on both sides of the valley.
- Measure the length of the valley.
- With sheet metal cutters, cut the metal valley flashing to the proper length.
- The new valley-shaped metal sheet makes a continuous surface for repelling water.
- Cut the metal sheeting to match the angle of the roof at the top of the valley.
- Insert the metal sheeting into the valley.
- Nail the metal sheeting with roofing nails about every 12 inches on its outer edges.
- The next stage of how to fix a shingle roof valley places new shingles over the edges of the metal sheeting.
- For shingling, start at the bottom.
- Cut shingles to fit under the old shingles and leave the central point of the metal valley exposed.
- Line up each new shingle with the existing rows of shingles.
- Drive nails in the upper edge of each shingle.
- Place the next shingle so that it overlaps the nails of the shingle below it.
- Complete the shingling on both sides of the new metal valley sheeting.