After initial excavation work started, a foundation inspection was required. The geotechnical engineer reevaluated the soil conditions, and it was found that an additional 18" was required to be excavated under the upper level of the house, due to poor soil conditions. Unfortunately, the lower level elevation was already close to the elevation of the septic field, so we could not just drop the whole house down. The best solution was to take 18" out from the building.
Problem solving time! If we increased the footing walls by 18" to regain the difference, that would have not been an economical solution, for the amount of structural fill that would need to be brought in, and the additional concrete work. The best solution was to drop the upper portion of the building by 12", and increasing the footing wall at the upper level by 6" to make up for the difference. This sounds simple, but a change like this sets off a chain reaction of adjustments.
First, the 12" was taken from the ceiling cavity. This also meant that we had to lose the upper level of the back deck. It also meant that the celling heights in the basement had to be strategically lowered, to allow the basement ductwork to be concealed above the ceiling, and windows in the basement would be shortened. The retaining wall adjacent to the garage was lowered by 12" (savings!), and the interior and exterior stair tread counts had to be adjusted. A step had to be introduced coming off of the deck at the garage, and a step needed to be added to the rear of the garage to make up for the difference (not pictured in the diagram above).
Because the upper level footings increased by 6", while the building elevation dropped by 12", the backfill at the footing walls exceeded the maximum of 24". Our solution was to drop the grade around the house, increase a step at the front porch, and to drop the siding material at the front so that visually the house looked the same.
We require reengineering at the footing between the garage and rest of the house because of the weight of the slab leaning against the footing wall and the crawl space, as well as the detail at the deck, and will have to submit this revision to the county.
This is an ongoing process, but we can say that we are lucky to have dedicated team to solve these issues together, step by step.
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