One of this year’s Angel Projects took place at San Miguel Chapel (sometimes also called the San Miguel Mission) in Santa Fe. Avigail Charnov, architectural conservator at Jablonksi Building Conservation and ASG member who organized the project, wanted AIC member’s to get involved and help in the restoration of this important historic structure. The restoration project of the chapel is being undertaken by Cornerstones Community Partnerships, a non-profit organization which works with communities to restore important historic monuments and structures in New Mexico. The projects they work on are those requested by communites and they are committed to involving the community in the work that takes place.They work primarily on adobe structures and incorporate traditional materials and methods in the restoration of the places they preserve.
This year’s all female team of Angels, made up of architectural, paper, paintings and objects conservators, worked with Cornerstone’s project members to make mud bricks that will be used in the repair of the historic walls of the church and re-plastered previously repaired walls.
History of San Miguel Chapel
San Miguel Chapel plays an important role in the history of Santa Fe. It is one of the oldest structures in the city and was originally built when the Spanish came into the area in 1610 (or 1620, the records are not so clear). The Franciscans who came to the area at that time brought with them Tlaxcalan Indians from Mexico, who had helped them conquer the Aztecs, to build the church. The church was in use until 1640 when it was destroyed but then rebuilt. It was destroyed again in 1680 during the Pueblo Revolt when the local indigenous people turned against the Spanish and colonization, as well as the imposition of the Catholic religion. The Spanish were pushed out of the area until 1692. When they reconquered the area, they saw that the local people had torn down the church as part of their rejection of Catholicism and the Spanish. But the Spanish were not deterred and rebuilt the church in 1710 (a date confirmed using dendrochronological dating of the timbers used to construct the church). This 18th century layout is the basic church layout we see today.
The mission became a school, St Michael’s High School, in the 1850’s. In the 1880’s, an earthquake caused structural damage to the church and it was going to be torn down, but the building was important to the community and the city and so it was saved. It was rebuilt in the Mission Style, which is what we see in most of the building today. The front however is in the Santa Fe style (modified in this style in 1955). One of the main changes that occurred at this time was to replace the mud plastered adobe with a cement stucco layer. Cement was also used to reinforce some of the adobe bricks. Areas of the roof that were flat were also altereed to have a pitch and drain into a courtyard on the southside of the church. These changes would cause problems in the future, but more about that in a bit.
In 1968, the high school grew too large for the chapel and associated buildings and moved to a different site. Over the years, the building was not maintained, though is still held church services, and was in need of repair. That’s when the community contacted Cornerstones for help.
Condition of the Chapel
The Chapel suffered damage primarily due to repairs done in the 1950’s which used materials with poor ageing and that were incompatible with the adobe. The stucco applied at this time covered up the adobe bricks so their condition could not be monitored for any maintenance to take place. Changes to the pitch of the roof also caused problems, as did poor drainage in the courtyard off the north side of the church and run off of rain water toward the front side of the chapel. Cornerstones worked with the Getty Conservation Institute who came out to conduct a condition assessment of the chapel. They found damage due to moisture and deterioration of wooden supports in the wall in addition to the items mentioned above.
The work Cornerstones has undertaken has mainly focused on removing all the stucco applied in the 1950’s, replacing any damaged/deteriorated adobe bricks, reinforcing and replacing the wooden beam supports and replastering the walls with mud. As part of the committment to community involvement they allow people to volunteer in the restoration process. That’s where this year’s Angels got to contribute and also learn about traditional building techniques.
The day started off by learning how to make mud bricks that will be used in the repair of the walls. The bricks are made by mixing alluvial soil (made of silt, clay and fine sand) with coarser sand and straw. The soil and coarse sand are mixed in a 2:1 ratio of soil:sand.
Straw is added after the soil and sand have been mixed a bit and some water has been added. The straw acts as a binder and helps to hold the mud together. The amount of straw added is a basket ball sized clump to each batch of 30:15 shovel-fulls of soil:sand.
Once mixed, the mud is taken in a wheel barrow over to the sidewalk where we’ll be making the mud bricks. The wooden brick molds are prewet first to make sure the mud doesn’t stick to them. The mud is then added to the mold (which makes 2 bricks at a time) and tamped into the mold by hand. When both sides of the mold have been filled, the mold is lifted and voila, you have mud bricks!
After making mud bricks, we learned how to make mud plaster and how to plaster the walls. Mud plaster is applied over the walls to create a protective layer over the bricks and to act as a sacrificial layer to the elements so the bricks don’t deteriorate so readily and don’t need to be replaced so often. The smooth plaster layer needs to be maintained and requires re-plastering about every 2 years.
To make the mud plaster, we first need some very fine and pure clay. The clay Cornerstones is using comes from Nambe. This clay dries to a color very similar to the 1950’s facade. The clay is first screened to remove large pieces and create a fine texture. The lumps of clay are broken up with a pick and then tossed against an upright screen.
The fine clay that comes through on the other side is added to water and mechanically mixed to make mud. The mud is then taken and mixed with sand and chopped straw. The mud to sand ratio for the plaster is 3:1. The amount of straw that is added is a few handfuls.
To apply the plaster, the wall is prewet first and then the plaster is applied with a large trowel. Not much smoothing or working is required, and too much smoothing can cause the plaster to fall off. The plaster is applied across the wall to create a layer about 1/8″ thick. We managed to replaster the lower half of a wall of the facade of the chapel and we did a pretty good job for the first time. But that’s no surprise since we’re all conservators and therefore perfectionists!
I had a great time volunteering for this project and loved learning how mud bricks are made. It was great to work with such an enthusiastic team of conservators and members of the Cornerstones project. It was also really satisfying to know that while we were having so much fun, we were also helping to restore an important historic structure and that the bricks we made that day, would some day be placed into the newly repaired walls of San Miguel Chapel. If you’re in the Santa Fe area and want to volunteer with Cornerstones at San Miguel Chapel, you can find more information here.