• Sunlight illuminates the top of historic Mission San José de Tumacácori church.

    Tumacácori

    National Historical Park Arizona

Working With Adobe and Plaster

“Tumacacori’s preservation will always depend more on a respect and knowledge of the building’s materials and for the place itself, than on a new technological breakthrough. This is the nature of the place and that is the nature of adobe.” - Historic Architect Anthony Crosby

Check out some details on preservation projects recently completed at Tumacácori:

Jesuit church foundation Convento Dome
Windows and door casings Storeroom (a.k.a. Granary) Lime kiln
Replacement adobes Melhok Ki


 
Applying lime plaster

Applying lime plaster to the west wall of the mission church.

NPS Photo by David Yubeta

With the passage of time the lime plaster, which protects the adobe blocks from moisture, deteriorates and falls away. It must be replaced on a regular basis as this aging process occurs to prevent loss of the adobe construction material.

 
Preparing the convento for lime plastering

Preparing the convento for the application of a new coat of lime plaster

NPS Photo by David Yubeta

So that the lime plaster properly adheres to the adobe, the surface of the blocks must be carefully cleaned and prepared before the lime plastering starts. All of the bits and pieces of the old lime plaster must be removed and the adobe blocks thoroughly cleaned of any outside debris before starting the process.
 
Lime plastering the convento
Applying a new coat of lime plaster to the east end of the convento
NPS Photo by David Yubeta
 
Ready for patinizing

The convento is now ready for the "patinizing," or antiquing of the lime plaster finish

NPS Photo by David Yubeta

Once the new coat of lime has been applied to the entire section of wall that needed the replacement plaster, it is ready for another process called "patinizing." This is an antiquing process applied to the finish that gives it the off-white color of aged lime plaster.

Did You Know?

San Cayetano de Calabazas

The mission name "San Cayetano de Calabazas" means Saint Cajetan of Squash (i.e. gourds, pumpkins) in English.