Things You'll Need:
- Waterproof underlay
- Hammer
- 3/4-inch roofing nails
- Roof cement
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Step 1
Line the valley with waterproof underlay. You will need to get some waterproof underlay, such as Water Shield, from your local home improvement store to provide an extra layer of waterproof protection. Be sure to start with the lower volume roof plane, which is the one that drains the least amount of water into the valley.
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Step 2
Start laying shingles. Lay shingles on the lower volume roof plane first with a hammer and 3/4-inch roofing nails. Lay the shingles through the center of the valley and at least 12 inches onto the higher volume roof plane. Press tightly when you are laying the shingles in the valley as to prevent any butting up, or bridging, of the roof shingles.
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Step 3
Chalk a guide line. After laying the shingles through the valley you will want to chalk a guide line. It will need to be parallel to the valley and it will need to be about 2 inches up from the the center on your higher volume plane. Then take some roof cement and spread it about 2 inches thick around 2 inches parallel and over from your chalk line actually on the higher volume plane side of that chalk line. This will be for your next row of shingles, so be prepared to lay them.
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Step 4
Lay shingles along your chalk line. Take some shingles and lay them diagonally, along the chalk line. You will want to put them directly down into the roof cement. Be sure to start at the eave's edge. You will only want to do one row of shingles.
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Step 5
Lay shingles on the higher volume roof plane. Use the diagonal valley row of shingles as a guide to lay shingles on the higher volume roof plane. You can chalk lines as a guide from the valley onto the higher volume roof plane. You can finish laying the shingles on the higher volume roof plane and seal the corners with roof cement to keep them in place. However, if you are using shingles with a self-seal strip you will not need the roof cement for the edges.
