Elevate the house and terrace in situ with additional fill placed under and around the house
From the Silman Report
Option A elevates the house and re-grades the landscape such that the house will be in its original location but above the flood levels. The work will involve exposing the existing foundations, temporarily jacking the entire structure so that the foundations can be demolished, and temporarily relocating the house off of its current footprint so the site can be re-graded. Nine additional feet of fill would be added to the site, new footings would be inserted to ensure an even bearing stratum beneath the building, and the house would be placed on top of these new foundations (at the new elevation).
The remaining land surrounding the house would be re-graded to properly transition the site lines, vegetation and walkways. The central utility shaft would also be lifted and altered. With this option, the house remains in its original location on the site and maintains its proximity to the Fox River. The majority of the work would revolve around landscaping with minimal work done on the structure. When completed, both the house and lower terrace will be raised above the assumed 100-year flood occurrence level, reducing (and most likely eliminating) their likelihood of being flooded in the future.
The major disadvantage to this option is that it completely transforms the structure’s interaction with the site and river. Re-grading will change how the structure and site were originally envisioned. As one stands in the house and looks southward, one will noticeably be elevated above the Fox River. Requiring an intense amount of fill soil, this higher elevation will also cut off visitors’ experiences with the boathouse and the feeling of physically interacting with the river.