For a roof to be able to shield you from the elements, it must be strong enough to support the weight of the shingles. Its thickness depends a lot on the size of the rafters. There are other factors though, including the sheathing and shingles. Feller Roofing of New Braunfels, the area’s most trusted roofing expert, discusses them here.
One of the many structural details you should consider when replacing or installing a new roof are the valleys. You have two options on how to seal this area, namely either via a closed or open valley method. How a valley is sealed depends on certain factors, including how the contractor you’re working with installs the roofing underlayment and shingles.