Performing reroofs on old historical buildings can be fun and challenging. In late 2017, Progressive Roofing- Dallas began the process of removing an older existing roof and replacing it with a more modern-made system that would somewhat reflect the old.
The Gregg County courthouse is located at 101 East Methvin, Longview, Texas. Built between 1931 and 1932 by C S Lambie & Company and designed by Architects Voelcker and Dixon. It is in an Art Deco style typical of the era with a mix of concrete and brick construction.
The original building had a coal-tar pitch BUR (Built Up Roof) system which still existed until it was removed by Progressive Roofing. Coal-tar pitch is the bitumen of a BUR system which is not often used in today’s roofing environment. Asphalt has become the bitumen of choice by roofers and manufacturers today. Asphalt is less expensive, widely available and easier to apply. However, the new roofing system would be neither coal-tar nor asphalt (BUR), but modified bitumen.
What is modified bitumen?
“(1) A bitumen modified by including one or more polymers (e.g., atactic polypropylene, styrene butadiene styrene); (2) composite sheets consisting of a polymer-modified bitumen often reinforced with various types of mats or films and sometimes surfaced with films, foils or mineral granules. “ -From NRCA (National Roofing Contractor Association.
Modified bitumen is a cost effective alternative to BUR. Since modified bitumen comes in the form of sheets versus separated components like BUR it is less expensive to install. Modified bitumen system is a very good alternative for the preservation efforts of historical buildings.
The deck of the old Gregg County courthouse is solid concrete with a lightweight concrete insulation with coal-tar pitch BUR. Progressive Roofing removed this system down to the solid concrete deck, installed new lightweight concrete with EPS foam panels, Siplast Parabase base sheet, Siplast Paradiene20 TG with a Siplast Paradiene 30 FR TG in bone white.