15th Century Miniature, The Cathedral Builders


“There is an old story of how the cathedral of Chartres was struck by lightning and burned to the ground. Then thousands of people came from all points of the compass, like a giant procession of ants, and together they began to rebuild the cathedral on its old site. They worked until the building was completed–master builders, artists, laborers, clowns, noblemen, priests, and burghers. But they all remained anonymous, and no one knows to this day who built the cathedral of Chartres….”

Elevation, Church of the St. Louis Abbey


This story, recounted in an essay on the relationship between art and spirituality by the Swedish filmmaker Igmar Bergman, is what comes to mind when I am given access to a collection of color photographs, made between 1960 and 1962. They show the construction of the Church of the St. Louis Abbey. The photographs are a complete visual record of the work on a building designed by architect Gyo Obata and engineered by Paul Weidlinger. Complementing the photographs are a set of working drawings produced by Weidlinger Associates from the architect’s design. Weidlinger and Obata are known, but the laborers who helped realize their design are forgotten.   The video below, which animates both the photos and the drawings, honors them.

Father Timothy Horner, also featured in the video, was one of the four Benedictine monks who met with the architect in the late 1950s to decide on a design for the church.   The radical approach that Father Timothy and Gyo Obata favored was almost rejected by the Abbey Prior. Then Obata asked for a consultation with Pier Luigi Nervi, the world renowned Italian architect and engineer of concrete shell structures. Nervi gave his blessing and the project went forward.

Floor Plan
In the floor plan the pews and choir surround the altar.

The unusual choice of a circular floor plan was driven by the monk’s desire to keep the congregation as close to the altar as possible; as participants in the Catholic ritual rather than spectators.

Another unusual characteristic was how the church was built. Several contractors bid on the job.   The low bid was from McCarthy Brothers Construction Company, a St. Louis, Missouri firm. Francis “Paddy” McCarthy recalled that among the bidders there was a “considerable difference of opinion as to what would constitute the most economical method of construction… There is no reason to be critical of any of the estimators who prepared bids on this project since each was compelled to rely upon his imagination to a great extent, rather than upon past experience…” The high bidders all anticipated using hollow wooden forms into which wet concrete would be poured. Only McCarthy suggested using the gunite or shotcrete method in which a relatively stiff (dry mix) is shot out of a high-pressure gun and adheres to a single-surface form. You can see this process in the video.

Some early mistakes were made. According to Father Timothy the consistency of the concrete was carefully vetted at the facility from which the cement trucks were dispatched but disbelieving drivers, unused to dry loads, added water to the mix en-route to the construction site. When the mixture was shot onto the forms it slid right off and the loads had to be dumped.

Autosave-File vom d-lab2/3 der AgfaPhoto GmbH
A crane was used to reposition the concrete forms.

Once the issue of was resolved the church was poured in sections. There are twenty parabolic arch sections in the first tiers of the circular church but only five adjacent sections were poured at once. Once the concrete set the forms could be re-used and repositioned with a crane, leapfrogging around the circle.

Architectural Forum waxed rapshodic about the structure calling it “the most elaborate example yet on the North American continent of a circular building in a convoluted shell form. It’s three circling, pyramidal tiers of arches, which front the radiating vaults and a bellfry, look like some artfully folded and stacked-up white napkin.”


Completed in 1962, the Saint Louis Priory Chapel was a career-defining project for Gyo Obata and earned his firm, Helmuth, Obata & Kassabaum (HOK) its first national recognition. The McCarthy Brothers made a profit of $33,000 on its low bid of $538,000. Weidlinger Associates added another completely unique shell structure to it’s list of engineering accomplishments. Key to the success of the project was the extraordinary cooperation between client, architect, engineer, and contractor.