921 Main Historic Structure Assessment

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DAA JDESIGN ARCH ITECTURE+INTER IORS 3.2 STRUCTURAL SYSTEM FOUNDATION SYSTEMS Description: The foundation walls are visible above grade at the outside perimeter of the building as well as visible from within a dug -out basement space. However, there are some areas of the foundation that are not entirely visible for analysis including in the southeast corner where the covered porch is located and those parts of the foundation that sit below grade. v�Access to the basement is through an exterior hatch on the west side of the building and the basement sits below the north -central and west parts of the building. There is a crawlspace along the east and south sides of the building. The foundation walls are constructed of concrete masonry block. A concrete masonry block foundation type is likely not original based on the date of construction, but it can be seen in the earliest photograph of the building in 1948. It is likely that there was originally a stone or brick foundation of crawlspace depth that was later replaced. There are three courses of CMU visible within the basement and from the exterior on the east side of the building. Some areas visible in the basement appear to either have a fourth course beneath grade or possibly a concrete footing. It could not be determined if a footing exists or if the block is grouted solid, as such analysis would require further destructive investigation. The basement space is stepped in from the CMU foundation as the foundation only goes to a crawlspace depth. It is likely that the basement portion is not original and was dug out to accommodate a coal furnace. There is a coal storage room on the north side of the basement with walls constructed primarily of CMU, but the exterior wall has layers of stacked stone beneath three layers of CMU. The stairs accessing the basement space are located on the west side of the building and this is the only area with poured concrete walls. Where the basement transitions to crawlspace, the grade cut is unsupported. The crawlspace areas approximately 2'/z feet deep whereas the basement is approximately 6'h feet deep, meaning that the grade cut is four feet of vertical, unsupported soil. The north side grade cut does not step in more than a couple of feet from the north foundation wall, which undermines the support of the north foundation. Additionally, there is a brick chimney visibly in the basement and it sits within the crawlspace area at the edge of one of the unsupported soil cuts. The crawlspace areas are primarily open to the basement area and therefore visible for analysis. However, there is a CMU wall between the basement and the crawlspace in the southeast and southwest corners of the building. The crawlspace of the southwest corner is still mostly visible from an opening within one of the CMU walls but the crawlspace in the southeast corner is not visible. It appears that this area sits beneath the covered front porch. Inside the basement looking towards the access hatch. Interior of the coal room. 921 MAIN PAGE - 18