Installing a new roof is not cheap and you do not want to be repeating the same process after a few years. To ensure that your roof will last as long as it should means to make use of quality materials and also proven installation methods.
To avoid premature failure of your new roof, it would be paramount to follow the best practices of asphalt shingle roof installation. Even before hiring a roofer, take some time and familiarize yourself with a few of these methods to get the most out of your exorbitant investment.
In order to protect sheathing edges and wind-driven rain from blowing under roofing along the eaves and rakes, opt to apply metal drip strips of suitable design. Overlap ends of drip strips at least one to one and a half inches where more than one length is required to protect a roof edge.
During application in vulnerable areas like rake edges, eaves and valleys, use of self-adhering underlayment (also called ice and water shield or peel-and-stick) is advisable. At eaves, successive courses should be applied over the drip edge and bonded to the bare roof deck, overlapped at the upper edges according to the manufacturer’s instructions so that the uppermost course extends at least 24 inches past the exterior wall supporting that part of the roof. Application of peel-and-stick is essential along the eaves of roofs prone to ice dams. Furthermore, it is also good insurance along rake edges and as valley flashing on all roofs regardless of climate.
During standard asphalt roofing assemblies, the roof deck is covered with asphalt-impregnated felt before shingles are applied. The specified minimum is typically no. 15 felt; no. 30 can also be used but is a bit heavier and more reliable. Between organic felts and synthetic underlayment, the latter is preferred as they are made from polyethylene or polypropylene, are waterproof, lighter, more tear-resistant and can be left to the weather for months without damage. The former are a bit fragile—prone to tearing under foot traffic and tend to wrinkle if they get the slightest bit wet.