Analysis of complete vs. selective demolition

Facility name: Memorial Health UMC Savannah

Lesson Learned/Best Practice

During the pre-construction and bidding process, selective demolition and pour back of an existing 4″ slab on grade was priced to account for plumbing and electrical underground systems. The process of selective demolition, as well as trenching for underground MEP systems, resulted in areas of cracked or unusable slab, which required additional demolition and pour back on a T&M basis. This additional work had minimal to no schedule impact, but did have a cost impact as described below.

5,000 SF of selective demolition and pour back was captured in the original scope of work at $17,242. The additional selective demolition and pour back totaled $23,752 for a cumulative scope cost of $41,476. Conversely, complete demolition and pour back of the entire slab (23,453 SF @ $3.55/SF) would total $83,258. While this cost analysis indicates that selective demolition and pour back is the most cost efficient process, we propose that an allowance be captured in the bidding phase to account for cracked and unusable slab following demolition and installation of MEP underground systems. Factoring such an allowance at the bidding phase will allow for competitive pricing to work in the Owner/GC favor, as T&M work may exceed competitive bidding costs.

Suggested Actions for Future Projects

Perform a cost analysis of complete versus selective demolition on existing slab on grades during the design/bidding process, and if selective demolition is found to be most cost efficient (as is the case here), include an allowance for additional selective demolition in the competitive bidding process.