"The strong shield that the synthetic underlayment puts on the roof translates into a lot of benefits to the builder," says Leonard. In addition to protecting the quality of the home, synthetic underlayment is a lot lighter, so it takes a smaller crew to install it. It only takes one worker to lift a 1,000-square-foot roll of synthetic, which weighs about the same as a felt roll of only 300-square-feet. The weight and ease of working with it cuts some time and money off the whole process."
"The nice thing is that installing synthetic roof underlayment is really the same as installing felt. You use the same overlap patterns and the same nailing pattern, so there is no training involved. In fact, it goes up a little bit quicker than felt, because it's not as slick and workers can stand on it more easily. If you have some dew outside, you don't have to wait until the sun comes out to dry up all water for the roof to be safe to work on. In the end, it saves time and helps prevent injuries from workers slipping and falling. We probably have about one injury a year on the felt. Considering that, the synthetic roofing underlayment pays for itself pretty quickly."
"The final result is a product that benefits both the builder and the homebuyer. There are a lot of reasons to use it that certainly justify the minimal extra expense."
Synthetic roof underlayments mimic the attributes of housewraps, serving as a secondary weather barrier with better resistance to tearing, moisture, and ultraviolet rays than traditional roofing felt.
Synthetic underlayments typically weigh less than felt building paper, can be manufactured with an anti-slip surface, and can withstand exposure to the elements for six months.
After hurricanes ravaged the South in 2005, many homes required quick roof repair and "drying in" to minimize further damage due to water intrusion. With limited resources, contractors triaged homes, repairing the critical components and installing synthetic underlayments as temporary roofing. The underlayments performed better than the blue tarps handed out by the Federal Emergency Management Agency. In addition, the underlayment didn't require replacement when a roofing crew eventually arrived to install shingles.
Two manufacturers, Elk and Grace, offer a Class A or B fire-rated synthetic underlayment.