As with many new construction projects, the original metal standing seam roof on the Luling High School, in the Luling Independent School District of Texas, was given short shrift during the building’s original construction in 1987.

The building’s design put aesthetics before functionality. The roof included many valleys, ridges and tips, and an internal gutter system that proved inadequate to accommodate drainage for its challenging design. As a result of ponding water, the building was never completely leak-free during its 23-year service life.

Things came to a head in 2008, during an especially heavy rainfall that cost the district $40,000 in damages and clean up. For a solution that would resolve the design flaws of the original assembly, the district turned to Sam Heffernan, locally based representative of high-performance roofing materials manufacturer, The Garland Company, which has been working with the district since the late 1980’s.

A thorough inspection revealed a combination of inadequate slope in some critical areas of the roof and an open seam design that failed to adequately protect against ponding water, were the two factors most responsible for the poor performance of the roof.

“The original design was asking too much of a standing seam roof,” Heffernan says. “There was no way to properly waterproof the internal gutters and valleys.”

Several alternative solutions were proposed to the school board, including a complete metal restoration assembly using urethane technology; a retrofit assembly using a metal overlay; and a new standing seam roof assembly.

Once these options were competitively bid, the school board opted for an insulated steel metal roofing retrofit with a sealed seam design that could provide additional waterproofing at crucial flashing junctures while simplifying flashing installation.

The specified solution, Garland’s R‑Mer Lite II insulated steel roofing system, made it inexpensive for the district to add tapered insulation and build up slope, allowing the installation contractor to fill the internal gutters with insulation before roofing over them. Since metal retrofits require a thorough evaluation by a structural engineer, the district requested the services of Pat Sullivan of QS Tech LLP to calculate the additional weight to the underlying system.

“Since the replacement roof chosen did not require a framing system and the overall system weight is less than one pound per square foot installed, the retrofit proved to be a perfect solution for this difficult design,” Sullivan says.

Contractor for the project, Mark Rusch of Tri-Lam Roofing and Waterproofing, first filled the 2‑7/8‑inch high metal standing seam flutes of the existing metal roof assembly with one layer of Dens-Deck sheet rock and one layer of Expanded Poly Styrene insulation. By filling the space between the metal flutes, the EPS insulation significantly improved the thermal resistance value, in comparison with the original design.

The roofing assembly itself consists of a 22-gauge metal grid system, to which the roofing panels are attached. The entire assembly was engineered specifically to meet all local building codes, including IBC 2006 as well as Factory Mutual 4471 – Class 1. In addition, the Dens Deck material has allowed the assembly to achieve its coveted Class A fire rating.

“The replacement roof is a deceptively light system that is easy and safe to work with,” Rusch says. “It goes down like a metal single ply, and is easy to cut, making it ideal for a job like this one where there are lots of angles, variations and levels. There is a big transition from the upper to the lower roof. The trapezoidal shape, combined with the minimal slope and all these angles coming into the roof made it a real challenge. With the temperature fluctuations we get here in Texas, there is a lot of movement in a metal roof.”

A complementary stucco-embossed, extra-strength R-Mer wall system was installed around the building’s four-foot fascia, with custom-engineered gutters and downspouts made of matching, pre-painted R‑Mer metal fascia to complete the project.

In addition to the energy saving benefits of the added insulation, the roof came with a highly reflective Energy Star qualified coating. “The white surface combined with the added insulation can save the owner up to $50,000 in energy costs annually,” Sullivan says. “It’s very hot in Texas. This year (2009) alone we had 65 days in a row over 100 degrees.”

Since the installation of the metal retrofit, the district has seen a significant reduction in air conditioning requirements. More importantly, for the first time in more than two decades, the facility is 100 percent leak free.

According to the high school’s business manager, Stephanie Timms, the retrofit solution is expected to provide waterproofing integrity for 30 years or longer. The warranty applies to the entire assembly, including all base flashings, gutters as well as the vertical wall panels.

Ironically, the replacement system has been able to provide the functionality the building’s architect had hoped for, without sacrificing the beautiful aesthetics of the facility’s design.