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Mr. and Mrs. Tatum March 16, 1995 Page 6 Poor Drainage Other investigators have commented on poor drainage in the area around the residence. They remark on conditions, especially in the garden area south of the residence, where the fall of the ground is very small and may be locally towards the structure. A location where we observed poor drainage is towards the wcst end of the south wall near the porch. However, there are no roof downspouts that discharge in this area, and we did not observe indications of water accumulation. In our opinion poor drainage cannot explain the recent settlement damage, because it appears that the drainage is essentially unchanged from the time the structure was built in the 1930's. It has been suggested that the poor drainage in conjunction with the clayey upper soils could be producing seasonal movements. However, this would not be a changed condition that could explain the recent distress. The poor drainage could have contributed to some of the on-going normal aging described earlier. 6. Foundation Deterioration Were the foundations to deteriorate or rot away, support would be lost to portions of the structure and distress could result. It has been suggested that water infiltration due to the poor drainage maybe weakening the adobe. However, as noted above, the drainage conditions appear unchanged for many years. Therefore, adobe softening is not likely to be the reason for the recent distress. To the extent we could observe it, the wooden elements bearing on the foundation were sound. No rotten lumber was observed in the foundation area. Mine Subsidence Previous investigators have discounted mine subsidence as the cause of the recent distress because they considered the workings to be too far away from the structure. However, we understand that the mining could have been within 200 to 300 feet of the structure. Thus, depending on the theory used for analysis, the residence could be at or within the potential subsidence zone. Mine subsidence has also been discounted because damage to the residence is centered at the front of the house, whereas the mining was to the south. In this regard we note that the angle of draw concept is a simplification of what actually happens. Theories relating to coal mine subsidence are based on empirical evidence and statistical analysis of data obtained over known mining conditions. In most mining situations actual subsidence can be quite erratic and is governed by many factors including the types of rock strata that exist over the roof of the mine, the orientation r:aro~.tzso t eo t .n.