In the weeks following Hurricane Katrina, Roofing pros were ordering synthetic underlayments rather than the standard protective blue tarps to cover damaged roofs.
Synthetic roofing underlayments, like LinerLock LL-140 can remain exposed to sun and rain for up to six months without wrinkling or tearing that allowed workers to start re-roofing jobs with the plan to finish the job months later when post-hurricane shingle shortages are expected to have abated. Since then, synthetic roofing underlayment began to receive its awareness and acceptance.
Although some roofers have already turned to asphalt/fiberglass blends since the late 1990s. The fiberglass lends strength to the paper, and was intended to address pros' concerns about traditional felt being slippery and prone to wrinkling when exposed to moisture, but still cannot satisfy increasing demands on efficiency and economic for modern building industries . A number of roofing companies have gone beyond blends to synthetic underlayments; although introduced more than a decade ago, synthetic underlayment use in the United States began swelling just in the past five years.
For new commercial or residential developments, non-asphalt synthetics are worth the added expense on material cost because saving costs in installation and work often can be delayed for up to 180 days for leaving the LL-140 dangerously exposed to the elements. Builders and pros are now experienced that synthetic underlayments are more durable, more resistant to ultraviolet radiation and sunlight, and more dimensionally stable that means paying more than for traditional felt will find the expense worthwhile. "There's becoming more and more demand for the higher-end products because people are seeing that the initial outlay can be more than justified over time," says Architect Magazine.
Synthetic roofing underlayment is created with a mix of polymers rather than asphalt, synthetic underlayments do not absorb water, which causes wrinkling and tearing in standard felt paper. Synthetics are more wind-resistant, lightweight, and longer lasting than traditional felt paper. Additionally, it was developed to be UL Class A fire rated.
In the meantime, weather-resistant fully adhered underlayments have taken the product category to a whole new level. Similar to LinerLock LL-IW series (Ice & Water self-adhesive), which are designed to protect against wind-driven rain and ice damming; whereas, the non-synthetic ice and water barriers are particularly valuable in northern climes. Additionally, LL-IW can be used in protecting in vulnerable areas, such as the eaves or lower edges of the roof.
Nevertheless, the biggest saving and benefit are recognized for using synthetic is saving on labor in installation. For instance, a 5000 square foot job requires 25 rolls of 30 lb felt compared to only 5 rolls of LL-140 that means extra time and labor to transport and carry the rolls onto the roof deck. The estimation also take into account the additional laps required to complete a job using felt paper, for instance, a rectangular roof deck that is 22 feet in height requires 8 laps (with a 3" overlap) of 36" wide felt paper whereas the same 22 feet can be covered with just 6 laps of 48" wide LL-140. As felt paper requires more laps to complete, it also requires more anchoring devices which adds time and additional costs. Furthermore, LL-140 is certified in using crown staples that means pros can really speed up the installation and cut down labor costs 30~50%.