Theses (Historic Preservation)

Document Type

Thesis or dissertation

Date of this Version



Suggested Citation:

Reynolds, Elizabeth Henley (2018). Non-Destructive Evaluation of George Nakashima's Modernist Thin-Shell Plywood Structure (Masters Thesis). University of Pennsylvania, Philadelphia, PA.


The purpose of this thesis is two-fold: to understand the construction and vulnerability of an open thin-shell plywood structure, and to propose a holistic and efficient program for assessment of thin-shell buildings using Non-Destructive Evaluation (NDE). This project focuses on the Pool House George Nakashima built in 1960, on his estate in New Hope, Pennsylvania. The structure is noteworthy for its conoid thin-shell roof, as part of a series of experimental roofs extant on the Nakashima Complex. While several other buildings on site employ these warped roofs, the rate of deterioration of the plywood assemblies is not fully understood.

This thesis complements a growing base of research for the George Nakashima Woodworker Complex and the Nakashima Foundation for Peace, including the Getty Foundation funded “George Nakashima Arts Building and Cloister Conservation and Management Plan” by PennPraxis (2017). This project utilizes Non-Destructive and Semi-Destructive Evaluation to ascertain the current condition of the Pool House thin-shell roof. This information can be used in conjunction with future research to understand the rate of deterioration and to serve as a catalyst for a long-term maintenance plan. This thesis includes an overview of George Nakashima and his career, a history of the Nakashima complex, a summary of thin-shell structures, and the use of plywood as a building material, both broadly and in the context of the George Nakashima Woodworker Complex. The methodology for the project is delineated, including procedures for implementing NDE through careful study of the building. The employed NDE methodology identifies the optimal approaches for meeting project objectives while working within a defined budget and expertise level. The intention of this methodology is to create a model for NDE that can be implemented in future building assessment projects. Eight methods for evaluation were selected and employed on the Pool House, including: visual examination, moisture content data collection, physical measurement, species identification, visual grading, sounding, infrared thermography, and coring. This thesis ultimately presents a series of findings, based on NDE, related to the composition and construction, changes in geometry, and material vulnerabilities of the Pool House roof. Lastly, the effectiveness of the employed NDE methods is presented.


NDE, building assessment, warped roofs, structural capacity, building material vulnerability



Date Posted: 11 June 2018