New Roofing System Helps Historic New Mexico Building
by Carter Slusher, Modified Bitumen and Insulation Systems Engineer, Firestone Building Products Co.
From Western Roofing Nov/Dec ’09
After serving primarily as an unoccupied storage facility for nearly 15 years, the historic Lister Building in Lovington, New Mexico, began its road to renovation with a new roofing system specified to replace an aged, badly damaged, and leaking built-up roofing (BUR) system.
Identify Building Needs
Built in 1931 by I.W. Lister, the two-story building is owned today by the Lea County Museum. Constructed with a unique slip-form concrete method of the early 20th century, the building’s exterior features a decorative façade that includes parapet walls ranging from three feet high along the back and sides to more than seven feet high in the front. Over the years, the existing 7,000-sq.ft. roof was repaired and patched several times. Multiple layers of built-up roofing materials formed a rigid and heavy covering over a wood-plank deck.
Additionally, two peaked, triangular-shaped saddles had been constructed on the rooftop to help move water toward scuppers. Both 130’-long structures, which were covered with shingles, are about ten feet wide at the building’s rear and narrow to a point at the front. Combined, they represent about 30% of the roof surface. Reroofing the local landmark presented several challenges:
- Remote location – Lovington is a small town located about 300 miles southeast of Albuquerque, New Mexico, and 200 miles southwest of Amarillo, Texas, making the coordination of materials, equipment, and installation crews difficult.
- Limited access – The building is adjacent to a movie theater and sits directly across the street from the county courthouse. Proximity to these public facilities and surrounding areas created concerns about fumes, odors, and smoke.
- Tight quarters – Improving drainage around the two unusual rooftop saddles was further complicated by three skylights set between them on the relatively small roof.
According to Vickie Crenshaw, president of Crenshaw Consulting Group in Hobbs, New Mexico, reroofing the Lister Building was a challenging, yet rewarding project because the goal was to design a long-term maintainable roof system while improving drainage and addressing the aging parapet walls without modifying the building’s exterior architecture.
Due to the poor condition of the old BUR system, a complete tear-off was required. Seeking a balance of high performance and cost effectiveness, a two-ply, cold-applied Firestone SBS modified bitumen system was specified. The total system offers the sustainable, maintainable, and reliable protection needed on the nearly 80-year-old building.
“A cold-applied SBS system was a great fit for this project because fumes, odors, and smoke from a traditional built-up roofing system application would have affected the nearby public facilities and activities held in the area,” Crenshaw said. “Plus, using a kettle to pump hot asphalt up two stories with another facility adjacent to the Lister Building would have been a difficult process.”
Tear-off and Replace
Amarillo, Texas-based Construction Services, a Tecta America Company, handled all aspects of the complete tear-off and roof replacement project. After removing the existing system down to the wood deck, Construction Services nailed a Firestone MB base sheet over the deck to establish a good installation surface.
Next, a layer of 2.5” Firestone ISO 95+(TM) polyiso was mechanically fastened to the deck. Where needed, tapered insulation was used to add slope and ensure positive drainage. Using multi-purpose cold adhesive, Construction Services then adhered a half-inch-thick, high-density polyiso cover board to the insulation, followed by a Firestone SBS modified bitumen base sheet and a white, granule-surfaced Firestone SBS FR cap sheet.
According to Tracy Honea, project manager/estimator for Construction Services, keeping the roof surface clean and not letting the adhesive get too cold or too warm is among the biggest challenges encountered when working with cold adhesives. “It is not a big problem; you just have to be aware of it,” he explained. “We installed the cold-applied system over a two and a half week period and the adhesive cured out very well.”
To avoid potential slippage of the membrane on the two peaked roofs at the center of the building, Construction Services saddled an entire roll of SBS modified bitumen over each ridge to ensure both sides had the same amount of material. Since the rooftop can be seen from a nearby building, this procedure ensured no sheet ended at either ridge, making it a more visually appealing roof surface.
Cold-applied systems use asphalt more efficiently. There has also been an increase in the FM and UL approvals with cold-applied systems in recent years.
To assist the Lea County Museum in making this project a reality, Firestone Building Products donated all roofing materials and provided specification direction and on-site technical support; Construction Services supplied the new skylights and roof hatch; and Steve Gendron, principal of Albuquerque-based Upland Corporation, Firestone representatives for New Mexico and Vickie Crenshaw donated much of their time and expertise.
“Restoring the Lister Building was an urgent need for the Lovington community, and it would not have been possible without the outstanding support of everyone involved,” Harris said. “Working together, the team showed a great commitment to southeastern New Mexico and helped preserve a piece of our history. Best of all, the roof is performing great and we couldn’t be happier.”