Self-Adhesive Underlayments Waterproof Buildings While Waiting for New Roofs

Oct. 17, 2005

Delays in roof renovations are increasing in many areas - particularly in Florida, where towns such as Ft. Myers (one of Lee County’s biggest cities) are expanding rapidly and new construction is using up resources. According to figures from Realty Executives, close to 10 million people, or three-quarters of Florida’s population, reside within a 150-mile radius of Ft. Myers. The numbers continue to grow each year.

Roof renovations have also been delayed by the rainfall that Florida is experiencing and the growing need in many established towns to maintain systems. But a growing concern in the roofing industry is that the low availability of roofing supplies is at the heart of many delayed projects. No matter the reason, many contractors are turning to self-adhesive underlayments to protect roof decks and to give the contractors some flexibility when things don’t go as planned.

Although many buildings are in need of a new roof, many are enduring “blue tarp syndrome” while they wait months to have a new roof installed because they are not getting immediate attention due to reduced product availability. Though some contractors are biting their nails, others are reassured by the ability of some underlayments to protect the roof before tiles can be installed.

Fairway Woods II, Ft. Myers, FL-based condominiums, is one of the many housing complexes that has jumped on the self-adhesive bandwagon to renovate its 12-building facility. “There is a considerable shift in roofers using self-adhered underlayments to waterproof buildings,” said Ken Kelly, owner of Naples, FL-based Kelly Roofing, a roofing company serving southwestern Florida. “The improvements that have been made to the self-adhesive underlayments make them more durable and reliable, but also more useful in delayed situations.”

One of the most valuable qualities of the improved self-adhesive membranes is that they can be exposed to the elements for up to 180 days without damage to the membrane or the substructure. “That timeframe gives roofers the opportunity to install the membrane on all buildings and then go back - sometimes months later - to install the roof tiles. Using the membrane gives us flexibility with construction schedules and unpredictable weather,” Kelly said.

Although neither weather nor product availability can be controlled by roofing contractors, they (unfortunately) take the blame for the situation. Kelly has been delayed in finishing the roof of Fairway Woods II by consecutive days of heavy rain and the challenge of finding new concrete tiles for the project because the roofing tile manufacturer discontinued the tiles he had ordered for the renovation.

But this delay did not concern Kelly - even though the underlayment had already been installed on the roof decks while waiting to be covered with tiles. Typically, this would be an issue, but Kelly knows that self-adhesive underlayments are now strong enough to remain watertight even if left uncovered for months.

While Floridians hope for the best but tend to expect the worst after last year’s storms, manufacturers are taking the lead to make underlayments stronger for whatever weather lies ahead. “We have lived and learned from our experiences,” said Kelly. “After the string of hurricanes last year, people want to make sure we are using a strong underlayment; and as a roofer, I want to be reassured by the manufacturers that I’m installing a dependable product.”

Though underlayment manufacturers support their products with the standard 10- and 20-year warranties, only exceptional products offer insurance premium discounts. Bloomington, IL-based State Farm Insurance, the nation’s largest insurance provider, offers insurance premium discounts for certain underlayments, including Polyglass’ Polystick TU Plus.

This underlayment was used for the Fairway Woods II condominiums and saved the homeowners hundreds of dollars in roof renovation costs. Minimizing this expense was a major benefit for owners, but they also received the benefit of the new roof not being compromised by a delay.

Prior to the installation of the self-adhesive underlayment, the existing roof had a tile roof, two layers of 30-pound felt paper, and wood battens securing it to the roof deck. Although the existing roof did not leak when it was first applied, it had begun to leak in several areas, which initially prompted the renovation.

In selecting the new roof underlayment, one major consideration was its ability to resist punctures prior to installation of the roof tiles. A variety of factors at the jobsite can result in damaged roof materials: wind, rain, traffic, heat, carelessness, or a combination of all these. “Membranes can puncture when installing them, but depending on the product, it can be even easier to puncture them at the jobsite prior to tile installation,” said Kelly, who has been in the roofing industry since 1993. “Just having the underlayment sit on the roof can cause its surface to become soft when exposed to the heat, creating holes before tile installation with some membranes.”

That problem has become an issue with crews and multiple trades working together.  The underlayment needs to be able to withstand the abuse from general construction traffic, as well as the elements. While Kelly admits that it doesn’t happen often, he says it’s a problem that can be avoided by using a product that can resist punctures.

According to tests conducted by the Washington, D.C.-based National Bureau of Standards, roof temperatures in Florida can rise as high as 171 degrees F. at 3 p.m., with a 95 degrees F. ambient. Some underlayments are not well-suited for extreme temperatures and can expand and contract, but a select few manufacturers in the roofing industry have developed specially formulated underlayments that can withstand heat up to 260 degrees F.

Another hazard involved with membranes is that the tile lugs, which are on the bottom of the tiles or barrel, can dig into the membrane, also causing punctures. “Roofers need to consider the pressure that heat puts on the underlayment before they even install it,” Kelly said. “That was a major factor in our choosing the POLYSTCKTU Plus’ top layer of fabric mesh that lies on top of the adhesive. It’s puncture resistant, so it does not melt or become susceptible to degradation.” The product is a homogenous rubberized asphalt waterproofing membrane, glass-fiber reinforced, with a high-strength polyester fabric on the upper surface [that] protects the membrane from pressure.

Equally important, the POLYSTICK TU Plus features a SealLap strip, an adhesive surface located at the edge of the membrane that allows the membrane to easily adhere at the overlaps. Many adhesive membranes do not have the strip around the perimeter, so when laying the overlapped systems into place, the granular adhesive sticks to granular. The granular surfaces do not adhere as tenaciously as the adhesive strips.

Three crews installed 3,000 squares of Polystick TU Plus on the 6-unit buildings that featured a 5:12 roof. Even though the underlayment was used under tile roofing, it can also be used as a metal roofing underlayment and on chimney flashings, skylight flashings, pipe penetrations, application at ridges and eaves, valley underlayments, and certain below-grade waterproofing applications.

Two other product features were beneficial on this project: its skid resistance and its split release feature, which allows contractors to pull one piece at a time, install it, and then pull the next piece and install it. “When long pieces of underlayment are involved in an application, you risk it buckling and leaving voids on the roof,” states Kelly.

Contractors are figuratively blown away by underlayments’ ability to withstand wind.  The underlayment on the 2-story stucco buildings of Fairway Woods II, for example, was not secured with batten system. Instead, the contractor relied on the underlayment to fully adhere to the roof for a maximum of 180 days.

Dick Foster, a Fairway Woods II board member responsible for maintenance of the buildings, says, “I liked Kelly Roofing’s recommendation because it was reliable. It was time to redo the roofs and we wanted a roofing system that would take care of the leakage problems.”

Although the roof renovation at Fairway Woods II involved a self-adhesive underlayment, many other roofs in Florida and other parts of the country continue to suffer from “blue tarp syndrome” because they aren’t covered by underlayments that have strong characteristics that can meet and exceed the expectations of many roofing contractors and building owners.

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