At noon on Wednesday, May 12, 1869, tragedy struck. The Pittsburgh Post reported the story: "The walls of the handsome new Catholic church under course of erection at Sewickley gave way. The heavy roof crashed through to the floor beneath it. It was in turn covered by the walls, which fell inside, crushing the timbers to splinters. The entire side walls fell down, but the tower and the front wall, as well as the real wall, remained standing. The roof was composed of heavy timber, and was covered with slate.

Buildings in the immediate vicinity were shaken by the crash, but fortunately no additional damage was done and no one was injured. It was expected that the church would have been ready for occupancy within a few weeks. Arrangements were already in the making for the dedication ceremonies. The congregation will suffer considerable inconvenience from this unfortunate accident, and the disappointment occasioned thereby will be keenly felt."

A slight spreading of the walls had been noticed by workmen prior to the collapse, but it was not considered serious. Faulty construction was blamed for the calamity, until a brief mention was made several years later of a severe storm. The records at the Weather Bureau indicate that the weather on May 12th was unusual: unseasonably hot in the morning until clouds from the west began to cover the area at 10:00 a.m. bringing with them thundershowers. It is quite possible that the crude weather reporting system of that time had no way of knowing if locally severe storms or possibly tornadoes occurred, contributing to the collapse of the structure.

The loss was estimated between $15,000 and $20,000 ...a small fortune in that day. At this point the determination and faith of Father Zwickert and his small congregation faced its biggest test. We can imagine how they endured heated discussions as to why the church collapsed, and formed plans for beginning the job of clearing the debris and finishing the structure. A mortgage of $10,000 carrying 10% interest, and $10,000 more of floating debts was the situation in which the parish found itself. The Pittsburgh Catholic reported: "Father Zwickert will tour the diocese to solicit subscriptions to aid the poor people in their hour of need."

On Thanksgiving Day, November 24, 1870, a very thankful parish dedicated its new church. Saint Philomena's choir boarded the 8:30 a.m. train in Pittsburgh and traveled to Sewickley for the 11:00 a.m. ceremony. Bishop Domenec delivered the dedication sermon. A request in the Pittsburgh Catholic the previous week read: "Those who can make it convenient should not fail to attend and contribute their little mite toward defraying the expenses incurred. A dinner will be served up to those attending from a distance."