Missouri State Parks, a division of the Department of Natural Resources, recently commissioned an assessment of the masonry conditions of the gray sandstone ruins which were all that were left of the circa 1922 castle after a fire gutted the mansion in 1942. More than 20 years after stabilization projects in the late 1980s, the ruins are seeing the failure of some mortar and stone as well as the potential beginning of collapse in new areas - most notably around some of the archways, according to the recently completed assessment report from STRATA Architecture Inc. and Pishny Restoration Services.

The ruins of Ha Ha Tonka castle - arguably the most recognizable landmark of Lake of the Ozarks and among the most popular state parks in Missouri and indeed in the country - appears to be in need of some TLC with years of buffeting by winds and rain along with temperature extremes causing deterioration of the stone walls that have overlooked the Niangua waterway since before the lake itself came into being.
Missouri State Parks, a division of the Department of Natural Resources, recently commissioned an assessment of the masonry conditions of the gray sandstone ruins which were all that were left of the circa 1922 castle after a fire gutted the mansion in 1942. Abandoned for decades, the castle ruins and 2,697-acre estate were purchased and opened as a state park in 1978.
Now more than 20 years after stabilization projects in the late 1980s, the ruins are seeing the failure of some mortar and stone as well as the potential beginning of collapse in new areas - most notably around some of the archways, according to the recently completed assessment report from STRATA Architecture Inc. and Pishny Restoration Services.
With loose stones in certain areas, the park system fenced off two areas to protect visitors from potential hazards this spring and commissioned the assessment.
“Missouri State Parks believes safety is our top priority, so we have taken steps to protect the public. Our secondary concern is the stewardship of this important cultural resource so we are taking steps to fund and make the necessary repairs as quickly as possible. The division is examining contracts and options available to state parks to address the current situation,” commented MDNR Director of Communications Tom Bastian.
There was apparently some concern that the chimney extension on the east elevation may have been struck by lightning (this is an area now fenced off) after some stones were displaced following spring storms. The assessment, however, states that it is unclear if this movement at the chimneys was due to natural weathering or a lightning strike. Recently displaced stones were found at both the southern and northern chimneys on the east elevation during the April field visit for the assessment.
With the report completed on the castle and water tower ruins, Missouri State Parks is currently reviewing the recommendations for stabilization, according to Bastian.
STRATA assessed conditions and made recommendations for immediate repairs that need to be done within one year and short term repairs needed in two to five years.
The review of the condition of the east elevation of the ruins perhaps sums up the situation best, saying that the ruins are in “fair to good condition for a free-standing masonry wall fully exposed to weathering at both faces.”
The ruins have been exposed to the elements for nearly 75 years and are in fair overall condition considering, the report stated in its conclusion.
Mortar deterioration and loss is the “most predominant” repair needed, but two areas of structural instability at the north carriage entrance and the southeast corner chimney should be the focus of the most immediate repairs, according to the report’s concluding statement, in order to ensure safety and future stability of the surrounding wall sections. Miscellaneous repairs, the conclusion noted, are required on every wall but are not a potential for imminent failure.
Another overall issue appears to be uncertainty over what was actually done to the ruins during the 1980s stabilizations designed by Theiss Engineers, Inc. of St. Louis - which now appears to be defunct. The extent of reinforcing and the mortar that was used in those repairs is unclear.
While it is uncertain what mortar mix was used at that time, the assessment stated that replacement mortar is “too hard for the compressive strength of the stone” with the stone face being compromised before the mortar joint is.
According to the report, an attempt to remove a small section of mortar for testing at one location resulted in the stone failing and cracking.
“The mortar had been lapped onto the face of the stone and with the stone being the weaker material, water is forced through the face of the stone in lieu of the mortar joint and leading to erosion of the stones at the intersection of the mortar,” the report stated.
The report recommended that a supplemental field analysis be performed by a qualified structural engineer to determine the existing reinforcement and how the structure is vertically braced before moving forward with a final solution for repairs. A review of existing documentation of previous repairs in comparison to current code requirements, testing to identify the extent of steel reinforcing and masonry reinforcing ties installed in the 1980s stabilization and calculating structural strength based on previous stabilizations to determine validity of design were also recommended. Materials testing of stone and mortar was advised as well.
Immediate repairs recommended by STRATA for both the castle ruins and the water tower total $500,000 with another $165,000 in short term repairs advised.
“The division is currently reviewing all recommendations that were presented in the Comprehensive Assessment. These recommendations, and other improvements throughout the system, will be considered as the division works through its Capital Investment budget planning process,” said Bastian.
The primary source of funding for the state park system is half of the dedicated one-tenth-of-one-percent parks, soils and water sales tax, which provides about three-fourths of the division's budget for operation and development of state parks, according to Bastian. All additional funding comes from revenues generated in the state park system and some federal funds.
The tax was first approved by voters in 1984, and has since been reapproved by voters three times in 1988, 1996 and 2006. Two-thirds of voters approved the tax the last three times.

Ha Ha Tonka State Park saw 528,771 visitors in 2015 - the eighth most visited state park in the Missouri system. In 2015, the park also placed fourth in the country in a USA TODAY Best State Parks survey, being beaten out only by two state parks in New York and one in Michigan.
Exterior Walls
The overall assessment of the exterior of the ruins notes that the perimeter walls are in various stages of decline. In addition to displaced stones, there are several structurally defective stones within the exterior walls as well as delaminated stones.
In its recommendations for immediate repairs needed for the north elevation (another area that has been fenced off), the report indicated temporary wood shoring should be installed, and the section of wall with failing stones at the center archways above the carriage entrance should be downstacked and reconstructed with defective stones being replaced.
The report advised reconstruction in other spots as well, such as the eastern gable peak, and the west elevation has damaged and missing stone from key support locations in both of the buttress archways.
It should be noted though that there is a sandstone stockpile at the site that can be used as replacements to minimize the change in appearance.
From the south wall, three of four ventilation shafts at grade have also fully or partially collapsed and present a hazard to the public, according to the report. This area too has been fenced off and two of the collapsed areas have been infilled with stones by the parks department.

Interior Walls
The interior walls are in slightly worse condition than the exterior with the sandstone used there being softer and of poorer quality as these stones were never expected to be exposed to weathering and exterior temperature extremes.
According to the report, the interior condition is “poor to fair with the internal archways and bracing walls exhibiting higher level of breakdown … Deterioration is primarily located at the masonry opening surrounds including arches and lintels, at the tops of the walls, and throughout at the mortar joints.”
A high level of loss in structural integrity was found at the north carriage entrance where structural movement from the exterior wall has translated to the interior and at the southeast corner of the perimeter walls where the south wall has seen significant mortar loss and settlement cracking.

Water Tower
With the assessment of the castle ruins, the Parks division had an assessment done on the water tower and its roof.
There is a structural crack along the east and west elevations and has at least four loose and displaced stones. There is also a projection of five stones above the roof at the base of the north chimney elevation.
A large opening in the roof finishes at the southeast corner is baring the interior frame to the elements, and several shingles are missing on both the west and south elevations of the roof.

Immediate Repairs for Castle Ruins: $245,000
1. Stabilize mortar and mortar joints - repointing using a new mortar formula than used in the 1980s stabilization
2. Stabilize stones at the tops of the walls and at masonry opening surrounds
•Reset displaced stones and repoint
•Pin and epoxy any stones exhibiting movement
•Replace damaged, deteriorated and structurally unsound stones and wall caps
•Install grout and hydraulic lime injections at areas of significant cracking
•Replace intermediate stones with deterioration due to nature of the stone
3. Stabilize areas with structural settlement or movement cracking. Provide temporary shoring as required for repairs.
4. Repoint low height site walls with gray pointing mortar
5. Infill and repair ventilation shafts at south elevation

Immediate Repairs for Water Tower: $255,000
1. Replace tower roof in its entirety.
2. Reconstruct and repoint stone chimney.

Short-Term Repairs for Castle Ruins & Water Tower: $165,000
1. Address site grading for improved drainage away from the structures. Remove brush and overgrown vegetation.
2. Repoint mortar (ongoing) at the castle ruin interior walls.
3. Complete testing of sandstone samples to verify compressive strength and presence of consolidation or water repellant treatment (the 1980s project scope of work included this treatment but it is unclear if it was actually done).
4. Minor stabilization work at the water tower masonry to address spalling and surface delamination.

Long-Term Treatment: $150,000-$250,000
1. Wayfinding and story-telling signage throughout the site.
2. Fountain area reconstruction
3. Framework reconstruction at Carriage House/Stable to illustrate original form