CHC study reveals decay on Alamo’s iconic west facade

The iconic west facade of the [Alamo] (http://www.thealamo.org/) , Texas’ historic shrine to liberty, is slowly wearing down.

In a Texas A&M University [Center for Heritage Conservation] (http://chc.arch.tamu.edu/) study of the facade, center director Robert Warden found that the base of a decorative column flanking the Alamo’s main entrance has lost from 5 to 7 centimeters, or approximately 2 – 2.7 inches, of its limestone surface since 1960.

“Some might say that doesn’t sound like a whole lot, but over time, it adds up to a significant amount, especially if that rate increases in the future,” he said.

Warden will present his finding at the CHC’s 14 ^th Annual Historic Preservation Symposium, “ [The Alamo: Structure of History] (http://one.arch.tamu.edu/news/2015/1/15/heritage-symposium/) ,” which is set for Feb. 20 – 21 at the Langford Architecture Center on Texas A&M’s College Station campus. Warden will lecture 3:15 p.m. Feb. 21 in the Preston Geren Auditorium. Symposium [registration] (https://secure.touchnet.com/C21490_ustoresmobile/web/store_main.jsp?STOREID=20) is open through Feb 18.

The decorative accents on the old Spanish mission that today sits in the center of bustling downtown San Antonio have been subject to the elements since they were built in the mid-18th century.

“The bases were originally rectangular solids adorned with medallions or floral patterns that, if you look at them from the side, now look scooped, rather than straight,” said Warden. “It’s clear from photos of the building in the 1930s that material loss was already well under way.”

To determine the extent of the column base’s material loss, Warden created two virtual 3-D models of the west facade’s entrance — one, from a 1960 [Historic American Buildings Survey] (http://www.loc.gov/pictures/collection/hh/) , and another with current data gathered by the CHC’s digital laser scanning and recording equipment.

He created the models with assistance from Samer Al-Ratrout, then a Ph.D. architecture student and now vice dean of the School of Architecture of the Built Environment at German Jordanian University in Amman, Jordan.

Warden and Al-Ratrout used software to merge the models by registering their common points, then measured their differences.

“In the future, a deeper understanding of the rate and cause of the column base’s material loss could be gained from comparisons of additional 3-D models to the 1960 and 2014 models,” said Warden.

The project also analyzed changes to the facade that have occurred through the years from various causes, including repairs and alterations. That study, comparing and analyzing photographs of the Alamo taken in 1934, 1960 and 2014, was undertaken by Julie Rogers, associate director of the CHC and a senior architecture lecturer at Texas A&M, and Micaela Allen, an environmental design student.

The study was part of a larger CHC effort, funded by [Ewing Halsell Foundation] (http://www.ewinghalsell.org/includes/index.php) and administered by the Texas General Land Office, to create a database of highly-detailed 2- and 3-D models of the Alamo’s exterior and interior using the CHC’s digital scanning equipment.

The database will help Pam Rosser, the Alamo’s conservator, keep track of preservation work and maintenance issues at the site, where a small group of revolutionaries garrisoned in the former Spanish mission were defeated in 1836 by a much larger Mexican army unit.