P and D entered into a lease agreement for the construction and occupancy of a building. The major portion of the building was occupied by P, and the remainder was sublet by P to various satellite enterprises. Ten years later in 1967-8, the roof started to leak. Repairs were made, but eventually, it was determined that a new roof had to be installed. P sought and obtained competitive bids and awarded the job to the lowest bidder. The lease provided in part that the Lessors agreed to make repairs to the roof and exterior walls provided that they did not have any obligation to make repairs made necessary by the negligence or improper use by the Lessees, their sublessees, agents, or employees. The Lessees were required to keep the leased premises in good order and condition. Prior to the repairs, P did not review the lease to determine who had responsibility to fix the roof problem. By 1971, P knew that D was responsible for the roof problem and asked for reimbursement. P sued D. D claimed prejudice by P's required failure to notify them. It was established that P did not ask the roofing contractor regarding the cost of repair, nor did they inquire that for an extra $1200 they could have gotten a roof with a 20-year life expectancy rather than a 15 year one, nor was the cause of damage to the roof determined but that it may have been caused by improper servicing of the air conditioning equipment. D testified that as a contractor himself he might have been able to make the repairs at a lower cost. The trial court determined that P breached the contract to notify but that D was unjustly enriched and allowed P to recover $5,867. P appealed; the recovery should have been under the lease contract. D appealed as well.