Notice of Intent: Documentation and Implementation of Treatment Plans at Casa Grande Ruins

archived

Prehistoric finish plasters are clay-based, leanly bound, and soot deposits between individual layers have resulted in relatively weak interlayer bonds. In recent months, the rate of loss of these plasters appears to have increased; delamination between layers and at the substrate results in frequent losses, and fragments are routinely found on the floor at the bases of walls, indicating an active deterioration condition. The principal goals of plaster treatment are to a) preserve the archaeological, architectural, technological, and iconographic value of the finishes for future study; b) preserve the plasters in situ in their architectural context; and, c) retain, as much as possible, their physical integrity by using minimally invasive conservation materials and techniques. Both the contextual and material integrity of the plasters are critical for future study. Localized delamination can be treated successfully with various natural and/or synthetic adhesives. Care should be taken when treating sooted surfaces because the soot is highly soluble and can easily stain the plaster in the treatment area. Facsimiles will be prepared to test for staining and bond strength prior to in situ application.

High