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3.0 CONCLUSIONS It is BCI's professional opinion that the distress to the subject building is the result of a combination of factors, including possible sinkhole activity. Based on the results of our investigation, the minor distress to the building is primarily due to minor differential settlement of the foundation and interior floor slab related to long-term densification of variably loose sandy soils that support the structure. Relict tree root systems within the shallow soils near Unit 4622 may have contributed to the distress to the northwestern portion of the building. In addition, we found evidence of sinkhole activity in two of the four SPT borings completed at the site. Given these subsurface conditions and the apparent ongoing cracking distress to the building, a minor component of the differential settlement may be the result of ground settlement associated with developing sinkhole conditions. The analysis described in this report is of sufficient scope to identify sinkhole activity as a possible contributing factor to the damage within a reasonable, professional probability, as defined by §627.706-707 Florida Statutes. Primary factors in our conclusions include the following: • Evidence of sinkhole activity was encountered in borings SPT-1 and SPT-2 Multiple narrow intervals of very soft (weight-of-rod/hammer) soils were encountered from 43%z to 45'/2 feet and 53'/2 to 55 feet below grade in boring SPT-1, and 33'/z to 35 feet, 43'/2 to 46'/2 feet, and 47'/2 to 50 feet below grade in boring SPT-2. In addition, losses of drilling fluid circulation were associated with the very soft soil zones in these borings. Borings SPT-1 and SPT-2 were located near Unit 4622, which contained a greater concentration and magnitude of settlement distress than the other units. • Based on observations in our test pit excavations, the building foundation is embedded approximately 22 inches below grade. The hand cone penetrometer probes indicate the surficial sandy soils around the perimeter of the building and enclosed porches are variably loose to depths locally up to 102 inches below grade. These data indicate the foundation for the building is locally bearing on very loose to loose sandy soils, which are susceptible to the effects of long-term densification. Given these conditions, some minor differential settlement of the foundation structures and associated minor cracking may occur. • We observed two tree stumps on the west and northwest sides of Unit 4622. According to Mr. Yapple, two large trees with canopies extending over the building were removed in these locations. Typically, large trees will have root systems similar in width to the tree canopy. It is likely the root systems extend below the building foundation,potentially causing ground settlement as the wood material decays. • The cracks observed in the exterior concrete flatwork (sidewalks;� are related to drying shrinkage of the concrete mass and relief of generated tensile stress. In general, this condition is managed with properly spaced and constructed crack control joints and/or expansion joints. However, following their formation the cracks may widen or experience minor vertical offset resulting from minor differential settlement. ��;E;stde:3c�� ►��;,;�,rs�ati�,�-, F3C3 1';ajUct 1`�lc�. Q;_;�b13 C�i`c1114^C,' ��C}5S0!YS I��?Il<'3't f't`SCCIctiOli !Il;`C?';�;01"�l�(;C� /��1RI 7��. l i:�lli ��i?. i t�()(i,'.;�y� 1�<F�E �