Guastavino tile is the "Tile Arch System" patented in the United States in 1885 by Valencian (Spanish) architect and builder Rafael Guastavino (1842–1908). It is a technique for constructing robust, self-supporting arches and architectural vaults using interlocking terracotta tiles and layers of mortar to form a thin skin, with the tiles following the curve of the roof as opposed to horizontally (corbelling), or perpendicular to the curve (as in Roman vaulting). This is known as timbrel vaulting, because of supposed likeness to the skin of a timbrel or tambourine, or "Catalan vaulting". Guastavino tile is found in some of New York’s most prominent Beaux-Arts landmarks and in major buildings across the United States.
The Guastavino terracotta tiles are standardized, less than an inch thick, and approximately 6 inches (150 mm) by 12 inches (300 mm) across. They are usually set in three herringbone-pattern courses with a sandwich of thin layers of Portland cement. Unlike heavier stone construction, these tile domes could be built without centering. Each tile was cantilevered out over the open space, relying only on the quick drying cements developed by the company. Akoustolith was one of several trade names used by Guastavino.
In 2012, a group of students under supervision of MIT professor John Ochsendorf built a full-scale reproduction of a small Guastavino vault. The resulting structure was exhibited, as well as a time lapse video documenting the construction process.
Guastavino tile has both structural and aesthetic significance.
Structurally, the timbrel vault was based on traditional vernacular vaulting techniques already very familiar to Mediterranean architects, but not well known in America. Terracotta free-span timbrel vaults were far more economical and structurally resilient than the ancient Roman vaulting alternatives.
Guastavino wrote extensively about his system of "Cohesive Construction". As the name suggests, he believed that these timbrel vaults represented an innovation in structural engineering. The tile system provided solutions that were impossible with traditional masonry arches and vaults. Subsequent research has shown the timbrel vault is simply a thinner masonry vault than with traditional arches that produces horizontal thrust also, simply to a lesser degree due to its lighter weight.
Archival sources 
The Guastavino company was headquartered in Woburn, Massachusetts, in a building of their own design which still stands. The records and drawings of the Guastavino Fireproof Construction Company are now preserved by the Department of Drawings & Archives in the Avery Architectural and Fine Arts Library at Columbia University in New York City.
See also 
- Boston Public Library — first major Guastavino building installation in the US
- Catalan vault
- Glazed architectural terra-cotta
- First Church of Christ, Scientist (Cambridge, Massachusetts)
- Ed Koch Queensboro Bridge
- Biltmore Estate
- The standard reference is Ochsendorf, John; Freeman, Michael (Photographer), Guastavino Vaulting: The Art of Structural Tile, Princeton Architectural Press; 1st edition (September 22, 2010). ISBN 978-1568987415
- Ochsendorf, John. "Construction of a vault". Guastavino.net. Massachusetts Institute of Technology. Retrieved 20 March 2013.
- Salvador Tarrago, Guastavino Co. (1885–1962): Catalogue of Works in Catalonia and America (ISBN 84-88258-65-8)
Further reading 
- Ochsendorf, John ; photographs by Michael Freeman (2010). Guastavino vaulting : the art of structural tile. New York: Princeton Architectural Press. ISBN 978-1568987415.
|Wikimedia Commons has media related to: Guastavino tile|
- Guastavino.net: documenting Guastavino's work in the Boston area. This page provides copies of writings and patents by the Guastavinos as well.
- Rafaelguastavino.com: documenting Guastavino's work in New York City
- "CONSTRUCTION OF A VAULT", Massachusetts Institute of Technology (shows method of construction)
- Palaces for the People: Guastavino and America’s Great Public Spaces, Boston Public Library, September 28, 2012–February 24, 2013 (exhibition)
- Guastavino - NYC Restaurant