Faulty Workmanship and Completed Operations

My question has to do with faulty workmanship. I know that the CGL form covers the risk of defective work of subcontractors for completed operations, but does this apply to ongoing work? In this case, the building owner sues a general contractor for damage due to defective work of one of the subcontractors that results in damage to additional components of the building. The subcontractor negligently installed a foundation which then shifted, causing floor slabs to become uneven and damage to the wood flooring that was installed over the slabs. Is exclusion j(6) applicable here?

In connection with this, what defines when an insured's work is put to its intended purpose for purposes of triggering the completed operations coverage? Would the issuance of a temporary certificate of occupancy demonstrate that the work is completed?