Nonwovens Help Construction Go Green
demand for more energy efficient buildings increases the role of nonwovens in roofing and construction applications
By Karen McIntyre, Editor
Published March 20, 2008
Nonwovens are nothing new in the roofing and construction market. DuPont has been selling its Tyvek brand housewrap material there for decades and the use of spunbond polyester mats in roofing applications has steadily been replacing paper and other organic materials thanks to their ability to inhibit mold and mildew growth. As the construction market—like many markets—has become more eco-aware, nonwovens’ usage in this area has escalated.
Able to offer strength, durability, heat retention, moisture management and flexibility, nonwovens are used in many areas of the building envelope to help keep interiors cool in the summer and warm in the winter. In fact, according to a study from The Department of Energy, the use of a housewrap can lead to a 25-40% savings in energy costs. It’s benefits like these that have made the addition of a wrap basically standard in new home builds around the world.
“Nonwovens are being more and more used in construction applications,” said Arturo Horta, roofing market manager at DuPont Building Products. “Twenty five years ago, there were no nonwovens in the building industry. The default was black paper, heavy paper saturated with asphalt or tar, but these are being replaced by nonwovens. Nonwovens are important because they are flexible and versatile.”
After striking gold with its Tyvek housewrap product, which has become nearly synonymous with new construction, DuPont has during the last several years added to this product line to help seal other parts of the building envelope, like flashing for placement around windows and doors and most recently the roof with its new Sealed Attic System.
First introduced in Europe a decade ago, Tyvek Attic System was launched last year in North America. Based on DuPont’s proprietary flashspun technology, this product is designed to seal the attic to improve the air tightness of construction and reduce energy consumption.
“This product completes the building envelope we are talking about by building tight—air tight. Tyvek housewrap has been a key component for many years but it only seals around the walls. What has been missing is sealing the top of the house or the attic. It is the final component,” Mr. Horta explained.
Through a combination of air tightness and radiant heat, this system, which contains a metal coating and an aluminized layer, can reap an energy savings in the region of 10-15%. “Not only does it stop escaping energy, it also radiates heat into the house in the winter and out of the house in the summer,” Mr. Horta added.
While DuPont has been manufacturing its proprietary Tyvek nonwovens, based on its flashspun process, for more than 25 years, recent innovations, such as metallization, have allowed the material to offer even more benefits. This new technology has in fact become so important to DuPont that recent investments in Tyvek, like the one currently underway in Luxembourg, are largely centered on metallization, according to reports.
Also focusing on its housewrap product line is Fiberweb, which launched the next generation of its Typar product last month at the International Builders’ Show in Orlando. To demonstrate the effectiveness of Typar StormWrap, Fiberweb/Typar’s booth simulated the Miami-Dade County large missile impact criteria previously performed at Texas Tech University, and for Miami–Dade County approval, where a two-by-four is propelled at 34 mph toward several housewrap products to test their resistance to flying debris penetration. With the help of a pitching machine, visitors had the ability to launch baseballs at StormWrap and other leading housewraps to understand which product will meet this stringent code requirement and provide extra protection in extreme weather environments.
Housewrap, in general, is not usually top-of-mind when builders specify impact resistant products, but according to Bob Dahl, business director of Typar Construction Products, StormWrap is a revolutionary product that will help protect against the penetration of flying debris during hurricanes, tornadoes and high winds.
“We have tested StormWrap against one of the harshest building product impact resistance tests in the country and it meets the challenge. In fact, it’s so revolutionary it is the only weather-resistive barrier of its kind to meet this Miami-Dade County requirement as well as Florida building codes, the strictest building codes in the nation for extreme weather,” said Mr. Dahl.
Last year, Johns Manville, a major player in the roofing market, threw its hat into the ring that is the housewrap market with the launch of Gorilla Wrap, which replaced an existing housewrap product. According to JM’s market leader for roofing, Mark Clawson, this product was really built around the green concept and the result is a product that offers energy efficiency, clean air and reduces the spread of mold and moisture. Following the success of GorillaWrap, JM is looking at other wrap applications, particularly of the peel-and-stick variety. “We supply the nonwovens as substrates for peel-and-stick applications for window wraps, ice and water wraps—all of the areas where you would expect to find wrap,” he said.
The peel-and-stick products allow builders to get away from using open flames and asphalt on rooftops, and they are among the many innovations that roofing and construction companies have come to expect from their nonwovens suppliers.
“Like a lot of new products, once they become standardized, the customers come to expect them as standard equipment,” Mr. Clawson explained. “It’s like electric windows in a car or upgraded features in home. Housewrap is becoming expected from homeowners.”
Insulating From The Inside Out
The push to be “green” is certainly a major one at Freudenberg Politex and Freudenberg Texbond, according to Rederico Pallini. “As vertically integrated suppliers producing polyester mat from 100% post consumer PET (soft drink bottles) for the roofing industry, we are committed to improving the environmental impact of our operations, as well as offering our customers an environmentally friendly product that can be marketed as ‘green’,” he said.
In the U.S., local, state and federal mandates, along with incentives, will continue to push “green” products into the construction industry. “We see new opportunities combining ‘green’ with energy efficient products, which will result in reduced usage of oil, save money and reduce greenhouse gas emissions,” Mr. Pallini added.
Like housewrap is protecting the building from the outside, insulation, also a nonwovens application, is keeping it warm, or cool, from the inside. As building insulation grows globally, particularly in connection with the growing attention paid to the environment and the necessity to reduce energy consumption. In recent years, Freudenberg Politex and Freudenberg Texbond have launched the new Building Materials division, offering the construction market a wide range of products for thermo acoustic insulation and building protection in a broad sense. “The environmentally friendly Ecozero panels have been joined by the products of the PAR family (PhonoPAR, ReflexPAR, AcquaPAR and others), able not only to satisfy technical specifications, but also to give added value thanks to their contribution to environmental issues,” Mr. Pallini said. “The insulating products successfully contribute to energy savings and most of them are furthermore manufactured with recycled raw materials (PET obtained from post consumer bottles).”
Also focusing on nonwovens insulation is Germany’s J.H. Ziegler. According to general manager Peter Hartwig, growth in this segment is being driven by increased heating costs. “Polyester nonwovens have advantages compared to other insulation techniques due to weight, light permeation and handling,” he said.
Up On the Roof
As the rate of new home builds in North America continues to decline, nonwovens manufacturers supplying the roofing and construction market have had to work hard to create innovative new products that can increase the value of existing homes to find growth. For roofing and construction specialist Johns Manville, true growth is occurring in underlayment products where polyester and fiberglass maps are replacing paper and organic-type products. “Nonwovens are offering strength, durability, flexibility and low costs,” said JM’s Mr. Clawson. “You can even take it one step further in saying that paper is a source of mold growth and as mold becomes more and more of a concern for homeowners and builders, the synthetics are becoming more attractive.”
Last year, JM launched its Durabase product, which uses spunbond technology and asphalt to offer a more durable underlayment product in mainly residential applications. Residential roofing is basically a recession-proof market, driven by needs. “The residential roofing market is weighted more heavily (80%) toward reroofing than new construction,” Mr. Clawson said. “While the new housing construction piece is definitely holding the industry back, the other part continues forward. Typically roofs need to be replaced every 18-20 years so there is always a market for these materials.”
Recent roofing market entry DuPont is applying its Advanced Composite Technology, which combines a number of polymers and initially targeted medical applications, to develop DuPont Roofliner with Elvaloy, a new underlayment product launched just three months ago.
DuPont’s Elvaloy polymer has been used in roofing for a long time where it adds strength, stability and flexibility to roofing substrates. When combined with DuPont’s ACT, the result is a strong, tractable product that is thermally and UV stable with water barrier attributes.
One roll of DuPont roofliner can replace five rolls of felt because of its strength, according to Mr. Horta. Additionally, the product is much more efficient and easier to install. “The roofers like it. Once they use it once they don’t want to go back. It’s also cleaner and offers a more professional look. Felt tends to curl so it doesn’t look that neat when the shingles are placed on it.”
Outside The Box
New products and examination of new markets has been a strategy for manufacturers looking to make up for a declining construction market, which some experts say has been down as much as 10% during the past two years.
“We try to offer our customers increased value to better differentiate themselves,” Mr. Horta said. “We have also implemented an installer program. We have 190 specialists that work with our builders and our roofers to make sure they understand how to use our product to get the most out of them.”
When talking about roofing in particular, Freudenberg Texbond’s Richard Shaw explained how in North America, the low slope modified bitumen (MB) roll roofing market declined 10%-15% in 2007 compared to 2006. Although Freudenberg Texbond realized a slight gain in 2007, there was a sales volume decline in certain regions and with roofing manufacturers who declined to participate in low price promotions to move volume, he added. “ With raw material cost increasing and volume declining, some manufactures chose to reduce operating schedules, while other manufacturers tried to move more product by offering low price promotions. Low slope has not declined to the magnitude of steep/residential roofing, where regional decline has been reported in the 50% range. The decline in residential roofing is due to a 50% reduction in new housing starts as well as the lack of named hurricanes in the gulf coast. In addition, many residential roofs that would need to be replaced in 2007 and 2008 were replaced in 2005 after the many hurricanes that hit Florida and the gulf coast.”
However, the real potential of the North American residential construction market will not be realized in the short term due to the depressed housing market as well as problems associated with sub prime lending and the weak economic forecast, he predicted.
In the meantime, Freudenberg Politex has been able to develop new composites and laminated products based on nonwovens, thus taking advantage of both the unique performances of nonwovens and the additional features granted by the other layers, such as heat reflecting aluminum or breathable films.
Also benefiting the company is a recent investment in Russia, which will help it respond to increased living standards in the emerging countries of Eastern Europe, the Middle East and Asia. “The upgrading of buildings and infrastructures is naturally accompanied by the need for more advanced technologies and materials. In this scenario, insulation materials encounter growing interest and advanced waterproofing materials are gradually replacing poor backings used in the past,” Mr. Shaw continued.
That said, the roofing and construction market—although hurt to some degree by troubles in North America—will continue to increase its use of nonwoven materials to help its customers build homes to keep their residents safe and sound.