JAIC 2003, Volume 42, Number 1, Article 4 (pp. 39 to 58)
JAIC online
Journal of the American Institute for Conservation
JAIC 2003, Volume 42, Number 1, Article 4 (pp. 39 to 58)

MANAGING CHANGE: THE ROLE OF DOCUMENTATION AND CONDITION SURVEY AT MESA VERDE NATIONAL PARK

FRANK G. MATERO



5 ADDITIVE CONDITIONS


5.1 SOIL WASH AND RUNNELS

Soil wash occurs as a thin wash of tan-brown soil or deep runnels extending downward from the upper wall edges and banquette ledges. Soil wash flows down the surface according to divots and jogs in the upper masonry. The recording of variations in the soil wash patterns over two years within the same areas confirms an active condition of water runoff along the western edge of Kiva C, especially in the keyhole and to the north. Active loss and areas of detachment, delamination, and deformation along the upper plaster edge of the banquette walls are all found in association with soil wash and runnels above.


5.2 EFFLORESCENCE

Naturally occurring carbonates, and to a lesser degree sulfates, constitute the major soluble salts present at Mug House. Salts are clearly visible as discrete nodules in the bedding mortar and stone in areas of high moisture saturation both along the front and the rear, depending on the source of moisture. Salt cycling appears to be more severe along the front wall, where summer rains and melting winter snow cause dissolution and recrystallization within these materials. As a result, both stones and mortar in areas along the upper banquette walls to either side of the pilasters display considerable efflorescence and decay due to repetitive, prolonged wetting from melting snow and rain.


5.3 COLOR CHANGE

Color change is most characteristically observed as a localized reddening of the plaster, mortar, and stone, most intense on the surface and gradually diminishing with depth. This color change is caused by the calcination and oxidation of the iron-containing minerals in the clays. Fire reddening occurs exclusively along the upper half of the banquette walls and especially on exposed stones that were covered by plaster visible in the 1960 Rohn photographs and now missing. Burning may have embrittled the plasters (as in Kiva B), resulting in loss through weathering. The location of the fire reddening along the upper half of the banquette wall suggests burning may have occurred after abandonment and roof collapse that might have protected the lower walls.


5.4 CARBON SOOT

The location of carbon soot staining at Kiva C complements the locations of fire reddening. That is to say, carbon soot blackening occurs on the upper walls of in situ stone and plaster fragments above the fire-reddened areas and not on the last plaster layer along the lower banquette wall. Continuous thick overall carbon soot application has also been found on elements in some kivas and rooms that appear to have been selectively exposed in combination with the application of colored washes. These situations suggest the conscious application and/or manipulation of carbon-sooted surfaces as a design element.


5.5 VEGETATION AND BIOGROWTH

No active plant growth currently exists in Kiva C; however, ample evidence exists in the form of dead root masses between plaster layers along the rear lower wall. Root growth preference between the plaster surface and the fill is evident from mineral root pseudomorphs on the surface of the plaster. These are calcium deposits leached and redeposited by the plant over time, replicating the form of the original root. Evidence of both forms of growth along the rear wall can be attributed to the moist conditions along the rear alcove and the presence of a favorable growing medium from the deteriorated wet plaster. Biogrowth or microflora of fungi and lichens also occurs in limited and isolated locations in all cases associated with previous or current areas of moisture.


5.6 PREVIOUS REPAIRS

At least six repair campaigns were identified at Mug House, the first beginning in 1935 by Earl Morris and Al Lancaster. With the full excavation of Mug House by Arthur Rohn from 1960 to 1962, the site was stabilized for projected visitation. At Kiva C, repairs involved reconstructing the upper walls by laying new and recycled stones in Portland cement bedding mortar and pointing with a shallow, tan soil-cement mortar, stabilizing the deflector, and rebuilding and strengthening the ventilator with iron support rods. This pointing is cracked and loose, with areas of loss exposing the hard, gray bedding mortar underneath. No attempts were made to stabilize the painted plasters of Kiva C upon exposure; however, field descriptions of the plasters and hand drawings of the mural paintings were made, indicating areas of mural no longer extant.


Copyright 2003 American Institution for Conservation of Historic & Artistic Works