Ruins Stabilization in the Southwestern United States
Publications in Archeology 10
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Appendix 2E

The following records contain detailed ruins stabilization information for Kin Ya-a, a classic site in Chaco Canyon National Monument. Techniques for stabilizing prehistoric stone masonry are included (figs. 99-119).

A small sector of the plaza and northwest corner of West Ruin, Aztec Ruins National Monument, Aztec, New Mexico. Earl H. Morris restored the Great Kiva in 1934. The two most important preservational considerations involved are (1) the erosion and rotting of soft sandstone masonry, particularly the basal courses of walls, hastened by capillary action and, at various times in the past, by improper surfaced drainage, and (2) the preservation of 21 prehistoric ceilings and the maintenance of modern, concealed roofs which protect them.



Chaco Canyon National Monument. Date: Sept-Oct., 1956. Ruin: Kin Ya-a. Kiva: Tower; Wall (N. S. E. W.): (NESW).


Orientation, plan and type (situation, evidence of additional stories, period of construction relative to surrounding rooms, evidence of burning, etc.): This is a circular kiva set within four square retaining walls, located along the north wall of the house mound and approximately in the center. The Tower Kiva forms the nucleus for the pueblo. This unique round tower within a square one is impressive because portions of the north and east enclosing walls stand 4 stories high. On both the east and west sides of the tower there are at least 3 tiers of rooms. The main house block, however, is to the south and is quite mounded over but contains perhaps 4-5 tiers of rooms. All exposed masonry appears to be of the same type, indicating a single construction period. The third and fourth stories of the inner, circular kiva burned.

Floor (floor type; additional notes): Site is not excavated and there is no data on this.

Roof (roof type; additional notes): No data.

Details (notes on doorways, lintels, etc.): See additional pages for detailed notes pertaining to condition description, materials, construction, etc., with respect to each individual wall of the kiva.


Date: Sept-Oct., 1956; Ruin: Kin Ya-a; Kiva: Tower; Wall (N. S. E. W.): NSEW. Personnel of party on job: R. Richert and six Navajos.

Justification: The fragile tower Kiva remnant, a unique architectural development of the Chaco Culture, was reinforced and repaired to preserve it in nearly an "as found and as is" condition as possible and in such manner which will not impair any future, proposed excavations.

References: The site is unexcavated and most references are only general. However, a listing of tree-ring dates appears in the following publication: Smiley, T. L., A Summary of Tree-Ring Dates from Some Southwestern Archeological Sites. University of Arizona Bulletin, vol. XXII, no. 4, Oct. 1951. Laboratory Bulletin of Tree-Ring Research, No. 5, Tucson, Arizona.

Condition, description: The Tower Kiva, north wall exterior. In profile this is an L-shaped wall remnant, the vertical arm of the L forming a narrow section 8' wide, beginning at the second story and tapering at the top to an area only one stone wide. It is four stories high, measuring 32' 10" from the base at present surface level to the top stone. The exposed base of the wall at the top of the debris slope is 4' 6" higher than the surrounding ground level; hence the assumed base of the wall is at least that much lower, making the wall 37' 4" high, conservatively.

Three beam stubs are embedded in the masonry in the north-south direction, the ends projecting slightly beyond the exterior facing. They are nearly in line one above the other, at the first, second, and third stories. They are not roof supports as they extend into the thick kiva corner and stop there. It would appear that they were either reinforcing ties for the kiva corner, or their projecting ends served as a support for some sort of balcony, or perhaps scaffolding along the outside for construction of this high wall.

At the first story level, in a horizontal line with, and to the west of the lower beam stub mentioned in the preceding paragraph are two square openings. These formerly held beams as they still retain the molds. Spaced at 5' 8" intervals with the first beam, they may have served as projections to hold a scaffolding or catwalk. About two rows of stones beneath, and closest to west opening, is a third square opening which is a ventilator and largest of the three (15" wide, 16" high). In cleaning the top of the wall section above these openings, there was found the lower part of a fourth: a T-shaped ventilator 12" wide at the base and 16" in width above the shoulder. The two ventilators in this wall were open to the kiva.

Beginning at the second story level, the wall is inset 3" to the south; and at the second story elevation it is inset 6", presumably to insure better balance for such a high wall.

At a height of 39" above present surface level, the exterior facing contains one row of extraordinarily large, oblong blocks, the largest measuring 51" long, 6 to 9" thick, and 9" wide or deep. As a rule, the stones in the lower story are thicker and larger than those in the upper three stories. The north wall exterior is further characterized by considerable spalls between the courses of large stone blocks. This straight wall averages 22" wide. For the most part it is faced on both sides, and has a core of smaller flat stones with irregular edges set in thick amounts of soil mortar.

Considering its spectacular height, the wall is in good condition, but must be strengthened by repairing, reinforcing and capping to preserve its present condition.

The Tower Kiva, north wall interior. (For illustrations covering work on north and east wall interiors see figures 103-111.) The north wall interior contains the north arc of the kiva. The kiva wall is not perfectly circular as there are at least two somewhat angular surfaces evident in the facing where the prehistoric builders were unable to make the square or oblong stones form a circular surface. The kiva wall at this north side has two eccentric ledges or benches. The lower bench varies from 0" to 20" above fill level and varies 0" in width at the east where it merges with the facing to 27" wide at the north side. Another short ledge is 7-1/2" above the lower and extends for a distance of only 67" along the north wall. Whether these very narrow ledges were ceremonial or utilitarian is unknown. The kiva must have been extremely deep, as the wall at the northeast corner within the kiva measures 19' above present fill line, and it is possible that this deep chamber had several floors and ceilings. The eccentric ledges may have supported crossbeams for these ceilings. Excavation of the interior of this interesting structure might provide the answers to some questions regarding an aberrant architectural form.

Materials, construction, etc.: The Tower Kiva, north wall exterior. The high, sloping east and west wall stubs were capped, extending the east stub slightly eastward to provide a short but strong buttress section. Two integral members were placed in the west stub where it rises vertically, beginning at the second story level, the members extending to those rising from the east wall. The second and third story ledges or insets were repaired. The several openings including the two square beam holes, and the ventilator beneath them, and the beam holes at the east side were all repaired. The large hole at the base of the wall was filled with repair masonry in cement, the rough interior core being set in cement and the face stones laid in matching tinted cement. Following the above work, the entire wall face was grouted, pointed, and respalled. It was necessary to reset a few loose stones here and there in the facing.

The two eccentric, offset ledges along the north arc just above fill line were repaired. The lower half of a T-shaped ventilator in the center of the wall between the second and third story levels was repaired. East and west stubs were reinforced with paired integral members in connection with work on north wall exterior, already described. Within the upper kiva wall (includes the upper, spire-like fragment) considerable face stones were reset, and, where core was exposed, this was reset and pointed with soil-mortar. At the very top spire fragment itself, paired T-shaped integral members were in stalled.

The Tower Kiva, east wall, exterior. This wall rises at the north end to the same height as the north wall against which it is abutted. Parts of four stories are clearly visible as indicated by three rows of savino sockets. In profile, the wall top slopes up from south to north, to the spire in wavy fashion. In the first floor ceiling level there are 23 savino sockets; in the second story ceiling, 13 savino sockets remain, seven of which still contain stubs. In the third story ceiling there are four savino stubs. This exterior or east side of the wall formed the west side of the first room adjacent to the tower kiva on the east. Facing contrasts sharply with that of north wall. Where as the north wall was composed of nice oblong blocks dressed on one side, and rather large as a rule, the face stones in the east walls are generally smaller, less well selected and shaped.

The wall was in rather poor condition. It had several vertical cracks, one of severe proportions. The most serious condition, however, was a large hole extending through the midsection at first story level where eroding beam sockets were producing an ever increasing opening.

East wall, interior. The two narrow benches mentioned in connection with north wall interior merge with the wall, i. e., disappear along the east wall. The fill is banked higher along this wall and the south wall than elsewhere. The hole in midsection extending through the wall, caused by breakdown of beam sockets on the exterior side, is larger on this side. Broken and missing face stones need replacement, rough exposed core in upper sections should be reset, and the vertical wall stub forming northeast corner reinforced.

Materials, construction, etc.: The Tower Kiva, east wall, exterior. The three rows of savinos and/or savino sockets, the vertical cracks, and the large hole at midsection were repaired. Entire facing was respalled, grouted and pointed.

East wall, interior. The south half of the top was horizontally capped. The vertical or sharply sloping north half was reinforced with paired integral members which arch up and cross over near the top spire and are joined with those from the north wall. Circular wall facing grouted and pointed and stones reset as needed. Large hole in center at fill line patched.

Condition, description: The Tower Kiva, south wall. Fill was banked up all along the south wall and the top was obscured at central portion. Thick core was exposed at both southeast and southwest corners. The remaining portion of circular kiva wall is lower at this point than along the other three quadrants. This area needs cleaning to obtain a base on which to perform repair work in order to preserve and show original wall outlines.

Materials, construction, etc.: The Tower Kiva, south wall. The top was cleaned to reveal the straight, south wall enclosing the kiva. The thick kiva corners and the straight enclosing wall were capped. The exposed facing of the interior, circular wall was gone over by grouting, pointing and respalling.

Condition, description: The Tower Kiva, west wall. The straight wall here encloses the west portion of the circular kiva. The kiva corners enclosed are exposed to a height of 6' above present fill line. Exterior wall facing is either missing or pretty well covered by fill. A 4' thick section of rough core is exposed at the northwest corner. At the center of the west wall and level with fill both inside and outside the room, is a large U-shaped opening probably caused by breakdown to timbers embedded in this wall which provided support for the ceiling in the room to the west. The wall core at this U-shaped opening is thin, loose, and porous and is deteriorating rapidly. Visitors who climb to the Tower Kiva enter the circular chamber at this point. Note: visitation to this little known area may be infrequent but there were three or four visitor groups at the ruins during our project within a period of one month.

Materials, construction, etc.: The Tower Kiva, west wall. Both northwest and southwest kiva corners were cleared of surface debris, and capped. The northwest outside corner was excavated until good foundation was encountered, and then the exterior facing was reset to a depth of 18 to 20 courses at the north end, and to a depth of 4 to 5 courses at the south end. The exposed core and veneer around the U-shaped opening in the central section was reset (figs. 115-117).

Figures 118 and 119 illustrate some work in progress on the Tower Kiva. Note the use and adaptability of tubular steel scaffolding.

FIGURE 99. General view of Kin Ya-a from the north. Tower Kiva occupies central part, flanked by house mounds on each side. Ruins stabilization work and supply area in the foreground.

FIGURE 100. Close-up of north wall, Tower Kiva.

FIGURE 101. Tower Kiva, north wall exterior. Note large hole at base, and eroded insets (arrows) where second, third and fourth stories were slightly stepped back.

FIGURE 102. Hole at base, square openings (the two upper held beams, the lower was a ventilator) and insets repaired and wall stubs capped. Beam stub at left and two beam holes in the line above (arrows) either represent reinforcing ties for kiva corner of supports for some sort of prehistoric scaffolding used in construction or a balcony.

FIGURE 103. General view of northeast interior of Tower Kiva at start of project. The circular wall is stepped back or inset at two points: (1) at narrow ledge or bench where workman is beginning repairs, and (2) where facing is gone, exposing core (arrow).

FIGURE 104. Another view showing general condition of lower part of interior.

FIGURE 105. Detail of hole in Tower Kiva caused by breakdown of savino sockets. The beams for the sockets extended part way into this wall from the opposite side, and originally supported the ceiling of the adjacent room.

FIGURE 106. Lower portion of Tower Kiva, north and east segments, after stabilization. Offset ledges repaired, holes filled with repair masonry, facing reset (arrows A), top capped and inset core (arrow B) grouted.

FIGURE 107. Tower Kiva, interior northeast corner, during installation of integral members to strengthen the highest wall action.

FIGURE 108. Upper portion of Tower Kiva, northeast corner interior, after the integral members were anchored in masonry.

FIGURE 109. Beginning the vertical, reinforced capping (arrows).

FIGURE 110. Integral members in the form of a T were installed in this top fragment of core masonry after the lower wall section had been strengthened to that point.

FIGURE 111. The wall at completion of stabilization. The wall is considerably strengthened and tightened, without a serious or objectionable alteration of the original profile.

FIGURE 112. Tower Kiva, east wall exterior at juncture with north wall stub (at sign). Note the vertical cracks, eroded savino sockets (arrows) and loose, fragile spire. Portions of 4 stories are visible.

FIGURE 113. View of Tower Kiva showing vertical cap.

FIGURE 114. View of Tower Kiva showing north wall stub buttressed, cracks repaired, savino sockets remolded, and facing grouted.

FIGURE 115. Tower Kiva, northwest corner.

FIGURE 116. North wall stub capped (arrows A), lower portion of west wall facing reset (B), and exposed portion of thick core grouted (C).

FIGURE 117. Tower Kiva, west wall. This fragmentary of the square tower enclosing a round one was repaired by resetting the facing (arrow A), capping and grouting the thick core (B).

FIGURE 118. Work on the highest portion of the tower. The scaffolding completely surrounded the structure. To provide maximum safety for the workmen, the three sets of scaffolding were anchored at the bases and across the top and through midsections.

FIGURE 119. Tower Kiva. Scaffolding was anchored on firm and level bases built of heavy timbers.

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Last Updated: 16-Apr-2007