By Mark James
The Lafayette, Louisiana Regional Airport, recently underwent a retrofit metal-over-metal re-roof and energy upgrade on their 114 Borman hangar building. The project was out of the ordinary for a typical roof replacement application due to the existing roof being a barreled/curved metal roof. All roof system types will eventually need replacing, even metal roofing is no exception to this. The roof coatings/paint and design standards of years past are inferior to the high performance systems offered today. Recently completed research funded by the Metal Construction Association, MCA, determined that Galvalume® coated steel roofing can last over 60 years.
The metal-over-metal re-roofing technique used on this project has been practiced for over 25 years, largely because the existing roof typically is not removed, which would otherwise expose the interior of the building to the elements. Since the old roof remains, the new metal roof installation is extremely safe and enables the building owner to upgrade its thermal resistance and upgrade the new roof’s resistance to wind and snow loads based on current building code specifications.
The metal-over-metal application requires steel sub-framing that is structurally attached to the existing roof’s support system before the new metal roof can be installed. In this case, the sub-framing was manufactured by Roof Hugger, Inc. of Odessa, FL, which has provided their products on over 60 million square feet of building roofs since 1991. For this project, seven-thousand lineal feet of new 16-gauge factory-notched steel sub-purlins were engineered to comply with the new 130-MPH wind speed for the Lafayette area. The sub-purlin depth was 5-inches to accommodate full thickness fiberglass rolled insulation with a thermal resistance value of R-13 to be installed in the cavity between the old and new roofs. Roof Hugger’s sub-framing systems can manufacture depths up to 12-inches.
The project’s roofing contractor, Roofing Solutions of Louisiana of Prairieville, LA, stated that 120-foot long metal roof panels were roll-formed on site, curved at ground level and then lifted to the existing roof. According to the contractor, this length made it very time consuming and challenging, taking up to 15 workers at a time to pre-stage the panels for installation atop the old roof. All other work went as expected, completing the 31,500 square foot re-roof in a matter of weeks. The new 24-gauge standing seam metal roof in a Regal White color was provided by McElroy Metal of Bossier City, LA. Metal-over-metal retrofit roofing is cost-effective both from a materials and labor standpoint.
To find out more about Roof Hugger, Inc. and McElroy Metal, Inc., visit their websites at