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For many years, visitors and staff noticed cracks on the inner and outer walls of the Old State House Museum. In the summer of 1995, the Arkansas Historic Preservation Program awarded the Old State House Museum a grant to conduct a structural analysis of the building. The contract was awarded to the Witsell, Evans & Rasco architectural firm of Little Rock. Project architects Charles Witsell and John Greer subcontracted with the engineering firm John Milner & Associates, of Pennsylvania, to consult on this monumental project, with work beginning that fall.
The analysis revealed serious problems with the building's structural integrity, mostly due to an inadequate foundation. The original foundation, often repaired but never substantially improved, consisted mainly of local field stone, or rubble. This foundation is easily viewed on the west side of the lawn, where it rises above ground level.
The original foundation, which varied in depth from only 16 to 24 inches, was thought to be sufficient by 1830s construction standards. It also lacked spread footings, which serve as a stabilizing element to resist lateral and vertical forces. Today's standards require spread footings that extend below the frost line, which the original, narrowly laid foundation did not do. Laying these footings beneath the frost line protects them from the damaging effects of extreme temperature variations.
In addition, the original drainage system no longer worked, leaving standing water around the foundation. a small spring located near the west wing did not help, either. Another contributing factor to the foundation's deterioration was that the foundation stone was covered with an outer coat of Portland cement, which trapped moisture. The constant presence of water caused the field stones, held together with mud-based mortar, to shift. The exterior walls, made of soft clay bricks, soaked up the water along the foundation, which then evaporated during dry periods. Frequent wet-dry cycles eventually caused cracks to form in the bricks.
The extremes of Arkansas weather also took their toll. Outside walls are subjected to temperatures that range from freezing cold to blistering hot. Inside, a museum must try to keep constant the temperature and humidity to protect the artifacts and people by keeping windows shut and using modern heating and air cooling systems. These two opposing forces exacerbated cracking of the walls.
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