"What is panel roofing?" you ask. Panel roofing is made with large sheets of material. This material can be metal, fiberglass or even some types of plastic (polycarbonate is of the more common plastic types and is often used in greenhouses). Panel roofs differ from shingle roofs in their appearance and how they are installed. The purpose of all roofs, whether made of roof panels or shingles, is to protect the structure below from the elements. Some roofs are better than others in the protection that they provide. Older styles of asphalt shingles had life-spans of 15 to 20 years. New higher-grade asphalt shingles may have life-spans of up to 40 years. New metal panel roofs, by comparison, have life-spans that start around 40 years and may reach up to 60 years or more.
Material Choices and Colors
The most common panel roof material by far is metal: steel, aluminum, copper or stainless steel. Aluminum and steel roofs need to be painted or have a coating applied (galvanized) to protect them from corrosion. Painted roof panels can be had in a rainbow of colors to complement the structure they are protecting, and they can add some great architectural style. Copper and stainless steel do not need anti-corrosion coatings due to their natural resistance, but these materials are very expensive.
Superior Fire Protection
Where I live in the Rocky Mountain West, wildfires are an ever-present concern. Steel roof panels by their very nature provide some of the best fire protection available. Aluminum roof panels will often need some special under-layment to obtain a "Class A" fire rating, but even without this added treatment, aluminum is much safer against wildfires that conventional asphalt roofing.
Lightweight and Green
Metal roofs also have a few other great things going for them. Compared to an asphalt roof, metal roof panels are typically about 50% lighter. They also may have a recycled component. While it varies by manufacturer, the recycled component can be as high as 30% or more. When the time comes to retire a metal roof, the metal can be recycled again and again. The rates of recycling for asphalt roofs are sadly far below that of metal.
More Architectural Variety
Another great advantage of panel roofing is the multitude of styles that are available. Panel roofing can be found in many profiles, from a basic standing seam to a whole host of other profiles. Corrugated panel roofing can bring a modern industrial style and are common in some urban areas that have undergone renovations.
Whether you are thinking about replacing an existing roof or are in the process of designing a new home, putting panel roofing over your head makes sense for many reasons. Metal roof panels may cost more than a basic asphalt shingle roof, but by the time you factor in the life-span and the environmental advantages, things balance out. Some manufacturers are even incorporating solar cells into their roof panels - but that is a whole different story.