Cover the roof with felt paper. First, before laying field shingles (“field” refers to the large extent of the roof within the boundaries of eaves, ridges and rakes), it is important to install a preparatory course of starting shingles that are manufactured specifically for that purpose. Now that you've conquered the underlayment and drip edge and charted your course, it's time to learn how to install roof tiles. Although this seems to contradict the principle of overlap, the installation of the drip edge over the subfloor in the rakes creates a clean edge of the roof and provides the attachment of the subfloor with greater resistance against wind lift.
The next time you read the package instructions or watch an instructional video on YouTube, you'll have a much better understanding of why shingles are installed as is. Install a drip edge on the lower edge of the roof to protect the fascia and the wooden structure below. As shingles are installed in the adjoining roof area, the end of each row of shingles is trimmed (cut) 2″ rearward of the valley centerline. A solid, watertight roof is absolutely essential for your home, but asphalt shingles that protect your roof from the elements don't last forever.
David Bitan is a roofing professional, licensed contractor, and owner and founder of Bumble Roofing based in Southern California. For even more in-depth information, or if you want to see and learn how professionals do it, check out this library of instructional videos on all aspects of tile installation and roofing components. The most common closed valley is a “closed cut valley”, where shingles are first installed over the entire roof area on one side of the valley, with each course of shingles extending at least 12″ across the center line of the valley. Because the nails must penetrate the ridges and the last row of roof shingles below, you will need longer nails to fully penetrate through them to the roof deck.
This tutorial is a great resource for anyone who wants to build a shingle roof or better understand what to expect from a roofing contractor. This project guide is a combination of those two items and covers replacement of existing roof covering, installation of underlayment and ice dam protection, first row placement, field tile laying, flashing, shingles and ventilation grilles, and more. Learn how to prepare the roof for shingles, lay even rows, and install ridge shingles like the experts do. The last piece of the ridge should be nailed into place and since this will be the only place on the roof where the nails are directly exposed, the nail heads should be sealed and covered with an asphalt cement suitable for the roof.