In the meantime, preparatory masonry work has begun in other parts of the cellar as well.
Masonry Probes
The Preservation team conducted masonry probes to understand the extent of deterioration within the cellar. By doing so, the team can determine whether particular stones require replacement or if a stone veneer is a viable restoration option. Understanding the depth of deterioration allows the Preservation team to develop an informed repair plan.
In some cases, the probing process is akin to taking dendrochronological samples, where the probe penetrates the stone to gauge its condition and depth. The team also collected mortar samples, which will aid in understanding the overall integrity and composition of the masonry.
The Preservation team also probed the brick and mortar around the Mansion’s north and south chimney stacks, located in the cellar. This will allow experts to assess the depth of the modern brick and mortar and determine how much of the original material remains.
The Veneering Process
With that information in hand, historic masonry specialists with Dominion Traditional Building Group began applying sandstone veneers to partially deteriorated stones in the cellar passageway. The process of veneering involves attaching a thinner piece of stone to the front of the existing stone, thereby maintaining aesthetic continuity while ensuring structural integrity.
Mortar and Brick Removal
Historically, mortar is sacrificial material, intended to deteriorate over time to protect the masonry. Modern hard mortars such as Portland cement, when combined with porous 18th-century materials, can lead to unintended damage, as the moisture penetrates the stone or brick instead of the mortar.
Experts with Dominion Traditional Building Group began removing modern cement from the brick wall along the passage. Eventually, the cement will be replaced with a soft, lime mortar, like that used in the original construction. They also began removing some modern brick and concrete around the Mansion’s north and south chimney stacks.
