October 29, 2019
6:00pm - 7:30pm
Quinn Evans Architects
2121 Ward Place NW
Washington, DC 20037
Closest Metro Stop: Dupont Circle (red line)
Renovation of the Lincoln Memorial Roof
Presented by: Charles Thompson, Associate at Quinn Evans Architects
Dedicated in May 1922, the Lincoln Memorial is a major tourist attraction and a symbolic center of positive race relations. The architect was Henry Bacon; the designer of the 1920 Abraham Lincoln statue was Daniel Chester French, and the painter of the interior murals was Jules Guerin. Keeping this significant and valuable marble structure secure meant the repair of the roof and its supporting structure. The roof replacement on the Lincoln Memorial was precipitated by four primary conditions: the presence of heaving in isolated locations, ponding of water around roof drains, the need to replace existing drains, and the bulging of flashing around perimeter walls.
The design process for the new roof consisted of, first, exploratory probes to examine different areas the failing roof. After a better understanding of the underlying conditions, the design team determined that replacing the roof with a new PRMA system and the entire replacement of the existing concrete topping slab was the most appropriate solution.
Replacing the existing PRMA roof required the removal of slate pavers on pedestals, foam insulation, polyethylene sheet, hot applied rubberized asphalt, polyester sheet, concrete slab, and limited portions of terra cotta block infill. Through this process, unforeseen conditions were encountered (as is typical with historic structures of this nature) resulting in updates to the original design. One example of this was in the installation of roof vents into the new PRMA roof to allow for the terra cotta infill beneath the assembly to dry. Another concern throughout the project was limiting the removal of historic material. Much of the copper flashing found on the roof was original to the construction of the memorial and thus was required to be reinstalled in place as much as possible.
This presentation will explore the replacement process, associated projects and the intricacies of working with such a monumental structure.
After attending this course, participants will be able to:
Describe the history of the Lincoln Memorial’s previous roofing systems;
Discuss the roof analysis process;
Explore ways to combine new and old materials effectively to create a roof that's technically sound and historically appropriate; and
Determine a reliable construction process for extremely valuable building types.
Charles Thompson is an associate at Quinn Evans Architects. He served as project architect for the Lincoln Memorial roof renovation.
Event is free for members and $25 for non-members. Please click here to register.
AIA credits: 1.5 HSW|LUs (credits pending)