Building products distributors are keenly aware that the roofing underlayment industry has undergone tremendous economic upheavals in the new millennium. For more than a century, asphalt-saturated organic felts dominated as the de facto standard for residential roofing. That is certainly no longer the case!

Today, by some estimates, more than 75 percent of the underlayment market share has been captured by synthetics and premium modified bitumen membranes, especially for use under tile and metal roofing.

In the closing years of the last century, traditional asphalt-saturated felts were still the mainstay of residential roofing. However, since then, strong forces have been at work in the underlayment marketplace. One of the main reasons is that traditional asphalt-saturated felt has weaknesses.

Drawbacks include the following:

• It tears easily.
• It exhibits wrinkles after being left exposed for a few days.
• It is prone to degradation from UV (ultraviolet) exposure.
• It cannot be left exposed for long periods after installation.

Additional factors leading to the decline of asphalt-saturated felts are 1) the introduction of new building code requirements to protect homes from severe storm damage, 2) better home designs, and 3) the need to prevent ice damming. Home builders and roofing contractors responded to these challenges remarkably fast and manufacturers have been quick to meet their demands for new types of underlayment products.

Dry felt is stocked in a warehouse before asphalt saturation. Prior to 2000, traditional asphalt-saturated felts were the dominant underlayment for residential roofing.

Severe Storm Seasons

Severe storm seasons affected the underlayment marketplace in more ways than one. The active hurricane seasons in the middle of the last decade created a demand for labor as well as a shortage in primary roofing materials such as tile and shingles in some markets. There were reports of roofing contractors waiting weeks or months for delivery of primary roof materials. Underlayment was left exposed for as long as six months or longer and, in some cases, underlayment material had to be torn off and re-installed. Asphalt saturated felts did not perform well and for all underlayments exposure limits came into focus.

After natural calamities such as the numerous hurricanes that wreaked havoc in Florida in the early 2000s, new building codes began to encourage and, in some cases, dictate the use of secondary water barriers. The extra cost of a secondary water barrier more than offsets potential losses from consequential damages.

Better Home Designs

New construction and a better understanding of ventilation allowed for the installation of residential roofs with a watertight secondary water barrier. Much new construction occurred in Southern regions where air-conditioning is more common than heating. These new home designs with modern roof venting systems favor alternative underlayment materials, including premium self-adhering underlayments as well as synthetic underlayments. Nowadays new homes are designed for optimal energy performance that is tailored to the regional climates.

Ice Damming

For Northern climates, protection against ice dams was addressed through the use of extra protection along the eaves. This extra protection was mandated in various building codes such as the International Building Code (IBC) and the International Residential Code (IRC).

The demand for protection against the harmful effects of ice damming spurred the development of modified bitumen membranes for residential roofing.

Another factor influencing the choice of underlayment is asphalt prices. As energy prices rose, oil refiners developed new, cost-effective ways to crack the heavier organic molecules found in crude oil to produce gasoline. Ironically, when used in roofing applications, asphalt is not a "fossil fuel" but the demand for fossil fuels affected the supply of asphalt and resulted in sharp increases in asphalt prices.

This new technology for cracking asphalt to make gasoline continues to place pricing pressure on asphalt. Synthetic underlayment does not contain asphalt, so it is not subject to the various factors that affect the crude oil industry. It should be noted, however, that synthetic underlayments are polyolefinic materials. These are also derived from petroleum and similar macro-economic factors have contributed to spikes in the prices of the synthetics. Ironically, polyolefin-based materials such as polyethylene and polypropylene raw material feed stocks for synthetics are typically manufactured in China and India so synthetic underlayment prices are subject to geopolitics such as global trade agreements.

Historical price data for one ton of liquid asphalt are tracked by the Maryland Asphalt Association Inc. Also, the U.S. Bureau of Labor Statistics (BLS) publishes a Product Price Index (PPI) for asphalt. (The BLS publishes only indexes, not actual or average prices as explained here.)

Specialty Underlayment

The emergence of specialty underlayment for residential roofing applications occurred over many years. Various modified bitumen-blends were developed in Europe in the 1960s and were eventually manufactured in the US in the 1980s.

Initially, modified bitumen membranes were intended for commercial roofing systems but, by the turn of the century, premium underlayment products made from modified bitumen were offered to residential roofing contractors.

In 2002 Tarco launched a comprehensive line of LeakBarrier® branded premium self-adhering underlayments. Since then the market experienced several years of double-digit growth. Contractors appreciated the labor savings, improved performance characteristics, longer exposure limits and durability of these products. Special underlayment products were developed for use under shingles, metal and tiles.

For residential roofing, Tarco developed no less than twelve types of premium underlayment products for various applications as outlined in its Quick Reference Product Guide. This new category of underlayment is now well established among residential roofing contractors.

Looking Backwards and Looking Ahead

One other major change that has occurred in the industry is the willingness of building materials distributors to assist residential contractors in choosing the product that is best for the customers. Good hindsight leads to good foresight. By understanding the past upheavals in the underlayment product category, building products distributors will be better prepared to service home builders and roofing contractors and in turn builders and contractors will be better prepared to service homeowners.

As we close the books on the second decade of the new millennium, I would like to extend our sincere thanks for all you do and all that we have accomplished so far in a tumultuous underlayment marketplace. I wish you a peaceful and prosperous new decade. All of us here at TARCO look forward to continuing to work with you in the "twenties" as we face new challenges together.