Some manufacturers of synthetic roof underlayment include Owens-Corning, DuPont and Tamco. While synthetic underlayment is more expensive than the asphalt-saturated felt of the past, it provides a more durable second plane of protection for the roof.
Synthetic roof underlayment must protect the surfaces underneath the material from moisture, while still allowing them to breathe. Their design allows the escape of the moisture the home occupants produce in their normal daily activities. These materials add less weight to the roof than traditional felt and resist exposure to the elements for up to six months. Manufacturers use materials including fiberglass, polypropylene and polyester in making them.