Ultrasonic Investigation for the Characterization and Evaluation of Guastavino Tile Vaults: A Pilot Study

The third biennial meeting of The Construction History Society of America was held at Massachusetts Institute of Technology in Cambridge MA November 2-3, 2012. This scholarly forum is a venue for professionals from a wide range of construction related disciplines to come together to exchange ideas and research findings about their passions for design, engineering, and preservation.

This year, in conjunction with the opening of the exhibit, Palaces for the People: Guastavino and America’s Great Public Spaces at Boston Public Library, all of Saturday’s agenda was devoted to the exploration of  topics pertaining to his work.

VA’s presentation, Evaluation of In-Service Tile Vaults, was based on findings from a pilot study performed on a mockup of a Guastavino vault with simulated faults, such as voids and delaminations, built into the vault as it was being constructed.  The abstract and full report are included below.


Presentation by Kelly Streeter, P.E. and Kent Diebolt
3rd Biennial Meeting of the Construction History Society of America
Cambridge, MA | November 3, 2012

In response to aging infrastructure in the United States, nondestructive evaluation (NDE) is increasingly used as a monitoring tool, a method of investigation and in a quality control capacity.  The adaptation of existing NDE techniques to the evaluation of historic architectural and structural materials provides great potential for increasing the information available to professionals evaluating historic structures.

Guastavino ceiling tiles on the south arcade of the Manhattan Municipal Building

Guastavino ceiling tiles on the south arcade of the Manhattan Municipal Building

The process of addressing the significant public safety concerns of aging tile assemblies, such as Guastavino tile vaults, can be complicated by the difficulty of access – the undersides of the tiles often soar over heavily-used public spaces commonly filled with pews and other structures which make temporary scaffolding problematic.  The proposed sounding method examines the feasibility of evaluating Guastavino tile vaults from the top, which would allow architects and engineers to evaluate the vaults from the often easily-accessible attic spaces, thereby reducing the need for expensive and disruptive scaffolding systems for evaluation.  This could also facilitate more frequent periodic inspections.

Engineers evaluating the structural condition of existing tile vaults often need to determine construction details, including combined wythe and mortar bed thicknesses, in order to model vaults. Hammer sounding is frequently employed to qualitatively evaluate the condition of the soffit layer of Guastavino tile.  The ultimate goal of this research path and the basis of this pilot study on the ultrasonic investigation of Guastavino tile vaults was the removal of the aural subjectivity inherent in hammersounding by the quantification of this same phenomenon: the differing acoustic quality of delaminated and bonded tiles.  By capturing and quantifying the impact response of steel hammer taps with an ultrasonic transducer and data acquisition system, the raw signals can be analyzed in the frequency domain using modern computational methods in an effort to characterize vault construction and condition.

Download the full report

Building a Vault in the Style of Rafael Guastavino


Kent Diebolt, founder of Vertical Access, recently spent two days in July working at the Massachusetts Institute of Technology (MIT) with John Ochsendorf, a group of his students and two masons from the International Masonry Institute (IMI), building a mock-up of a vault in the Guastavino style for the upcoming exhibition, Palaces for the People. Years since its first conception, John was recently successful in getting funding for a major exhibition that opens this fall at the Boston Public Library and will travel to the Museum of the City of New York and The National Building Museum in Washington, DC.

Our interest in the mock-up project was to construct portions of the vault with known faults (primarily delaminations between tile wythes). VA Partner Kelly Streeter has done some preliminary NDT testing using ultrasound to evaluate the structural integrity of multi-wythe tile vaults that has been promising. The MIT vault, constructed with known delaminations at varying depths will allow for more empirical testing of the technology. Kelly and Kent will be presenting the results of this ongoing research at the Construction History Society of America (CHSA) meeting at MIT this fall.

We’d like to say thank you to John for including us in this effort. It was another great learning experience and a pleasure to share in the group’s enthusiasm for the work.

Additional Information:

The Guastavino Project at the Massachusetts Institute of Technology

VA Research, The Guastavino Timeline 1842 – 1968

Vertical Access Top 10 of 2010: Project 9 – Union Station, Toronto, ON

Toronto Union Station Great Hall

The Toronto Union Station is a grand monument to the age of railroad travel, which continues to serve as a major transportation hub both for local commuting lines and international inter-city travel. Located in Toronto city center, the railroad station was designed by Ross & Macdonald, a Montreal architecture firm with connections to Carrière and Hastings. Construction commenced in 1914 and the station was officially opened in 1927. Incorporated into the Beaux-Arts building are barrel vault ceilings by the Guastavino Company, including the coffered vault of the “Great Hall,” which measures 250 feet long by 84 feet wide and rises 88 feet above the floor at its apex. In 2009, the City of Toronto began a wide-reaching revitalization project that includes improvements to the railroad services, pedestrian traffic and retail facilities in the building.

Toronto Union Station coffered ceiling

Working with NORR and the Montreal-based architecture firm of Fournier, Gersovitz & Moss Architectes Associés, Derek Trelstad of Robert Silman Associates, Eric Jokinen of Jokinen Engineering Services and Kent Diebolt of Vertical Access were on-site in November 2010 for a close-up examination of a section of the Guastavino barrel vault in the Great Hall. The team examined the coffered face of the ceiling as well as the barrel vault exposed in the attic of the structure. The purpose of the investigation was to better understand the construction of the barrel vault and identify any fault patterns and conditions, at the small representative area, that should be planned for as part of the station revitalization.

Coffered ceiling detail

Read about Project 1: Union Theological Seminary Brown Tower
Read about Project 2: University of Buffalo Alumni Arena
Read about Project 3: United States Capitol Dome
Read about Project 4: Boston College Burns Library Tower
Read about Project 5: Mayo Clinic Gonda Building
Read about Project 6: Convent of the Sacred Heart School
Read about Project 7: The Galleria
Read about Project 8: Milwaukee Federal Building

Guastavino Biennial 2010 Final Lecture, by Kent Diebolt

Megan Reese with Rafael Guastavino

In the middle of February, I was in Barcelona, to attend the final lecture in the Guastavino Biennial lecture series at La Massa Theater in Vilassar de Dalt. The lecture was given by the Guastavino Prize winner, Megan Reese, an engineer working with Wiss Janney Elstner Associates, in New York City. Megan’s lecture was a report on her graduate work with Professor John Ochsendorf, at MIT. Megan’s was one of seven submissions for the prize, which included a trip to Vilassar de Dalt, an opportunity to present the final lecture in the inaugural series, a cash prize and publication of her work, in English, Spanish and Catalan.

This is taken from the Announcement of the Competition Results:

Guastavino Biennial Prize 2010: Megan Reese
First Distinction: Jillian Andrews
Second Distinction: Carlos Alberto Rodríguez Galván

STRUCTURAL ANALYSIS AND ASSESSMENT OF GUASTAVINO VAULTING, the work of Megan Reese is an excellent piece of work valuable in that if accomplishes its goal of developing, trough analysis and “real-world” case studies, a practical methodology for analyzing existing Guastavino structures. It progresses through more academic discussions into actual practice, to provide a framework for those practicing building conservation and historic preservation.

GUASTAVINO’S RELEVANCE IN MODERN ENGINEERING, the paper of Jillian Andrews offers a brief, succinct and cogent methodology for analyzing and considering another “real-world” Guastavino dome, in this case, a very significant and critically important piece of American architecture

ANALYSIS ON THE CO2 EMISSION IN THE ARCHITECTURE, the paper of Carlos Alberto Rodríguez Galván is interesting for his contribution in using Catalan vaults in new sustainable constructions.

A link to a lot more information on the Lecture and the competition may be found here:


The competition and celebratory program, honoring Guastavino’s life and his last project in Spain, the La Massa Theater in Vilassar de Dalt was conceived by the Mayor of the village, Llorenc Artigas, Director of Cultural Affairs, Xavier Yelo-Blat, and Secretary of the Jury, Agapit Boras, whom I have come to affectionately know as “The Three Musketeers”. The lectures, which took place between December, 2009 and December 2010, were attended by both Catalan architects and engineers, as well as village residents and other interested parties.

I served on this first competition jury, along with four Spanish colleagues, including the Jury Chair, Agapite Borras, Professors Mar Loren (Seville), Manuel Fortea (Badajoa), Jose Luis Gonzalez (Barcelona), and MIT Professor John Ochsendorf (Cambridge, MA).

Serving on this jury was an honor and an unique opportunity to learn more about ongoing international research on Catalan, or timbrel vaulting. Plans to undertake similar competitions on a biennial basis are in the works, so stay tuned for an announcement of the 2012 competition late in 2011.

The announcement for the 2010 Biennial Competition may be found here:

Guastavino Bienniale Announcement 2010 (English)

Site Visit to the Hospital de Sant Pau in Barcelona

by Kent Diebolt

In  mid-December of  2010, I travelled to Barcelona where Derek Trelstad, of Robert Silman Associates and I  were given a tour of the Hospital de la Santa Creu i Sant Pau in the Eixample, near Gaudi’s Sagrada Familia. We were hosted by Jose Luis Gonzalez and Gloria Riba, both of whom I first met in 2004 when I was invited to speak at a conference on masonry vaulting sponsored by COAC, the Catalan equivalent of our AIA.

Hospital de la Santa Creu i Sant Pau

Hospital de la Santa Creu i Sant Pau, main entrance to World Heritage Site campus.

The Hospital de la Santa Creu i Sant Pau is one of two UNESCO World Heritage Sites in Barcelona designed by Lluís Domènech i Montaner, whom the New York Times recently described as  “Barcelona’s Other Architect”.  The article, which coincidentally ran a week after my return from Spain, can be found here. NYTimes 12/19/10

The historic, modernist hospital complex has become redundant due to construction of a new building to the north of the site. The entire historic campus is currently either under renovation or scheduled for restoration. Jose Luis was selected to undertake investigations of the Sant Manuel pavilion, which will house the new United Nations University Alliance of Civilizations campus. At the time of our visit, the Sant Manuel pavilion project was nearing completion of the demolition phase of work, with structural investigations scheduled to begin in early 2011.

There are abundant examples of Catalan/timbrel (Guastavino) vaulting throughout the hospital campus, including a very curious detail that forms the surface of the gabled roof. Neither Derek nor I had seen this previously, and it’s not clear what the rest of the roof deck assembly that supports the tile roof surface looks like. Probes of this location will be undertaken this winter under the direction of Jose Luis and Gloria, so more will be known shortly. Continue reading Site Visit to the Hospital de Sant Pau in Barcelona