Are you in the market for a new roof? If so, then you will find there are many options available in the roofing industry. These options can range from multiple variations of asphalt shingle types to many variations of metal panels.
One of the many questions that are presented to a professional contractor is: “can metal roofing be installed over shingles?”. The simple answer is yes. The dichotomous nature of installing metal over an existing shingle roof requires many steps. We will examine these steps in greater detail to help determine if retrofitting a metal roof over and existing asphalt shingle roof is an innovative idea.
There are several things you must consider before deciding to install a metal panel roof over an existing asphalt shingle roof. The first thing that must be determined is if the roof plywood or plank board decking is secure and solid underneath the existing roof. Essentially, the roof decking should not be damaged from water entering the old roof at any pinhole or any other penetration within the field of the roof. This will require a little investigative work prior to installing the new metal roof.
It is highly recommended, to inspect all roof decking and framing from the attic side of the roof. One must look for dark spots, moldy spots, water trails on plywood or roof decking, and or any cracked or split rafters. This should be done with great care, for one mistake can damage your ceilings or cause significant injury to oneself. After these things have been validated to be okay, then, the next step is to start preparing the roof.
New 1×4 wood strips must be installed vertically and horizontally every 24 inches throughout the roof plane on the horizontal from bottom to top. It is highly recommended to use wood screws to attach the new 1 x 4 wood strips. After this is complete and a holistic approach to the entire roof, then, it is time to install the roofing panels. Be mindful that all roof penetrations will have to be flashed with flashing boots that will work with the metal panel chosen for the roofing application.
In this step, choosing the metal panel is critical to the longevity of roof life. There are metal panels that screw through to that would on the face of the metal that are simply nothing more than fancy barn tin. The problem with fancy barn tin panels is that the rubber washers overtime will dry rot and fail, thus, creating a roof leak that can undermine all the reason a metal roof was chosen to begin with.
A straightforward way to avoid the face screwed roofing material is to use a hidden fastener metal panel. These types of panels are called standing metal seam. It is highly recommended when choosing a metal roof to think about longevity. Succinctly expressed, a hidden fastener panel is going to last the entire life of the metal with minimal chance of leaks other than failing roof penetrations over time.This is normal to all roof types.