College freshmen may already be familiar with the laundry list of things not to do when attending a Collegetown party: Don’t vomit on the carpet. Don’t break windows. Also, try not to punch walls.

But after a porch collapsed in the middle of a party at 208 Williams Street on Sunday, a representative from Pam Johnston Apartments added another precaution: Avoid “rhythmic vibration.”

“Please exercise caution if you are going to have a party on your porch. Another very important piece of information that we have become aware of due to this incident is that rhythmic vibration, such as dancing, can be even more damaging than jumping up and down on a structure,” the representative, Grant Wilder, wrote in an email obtained by The Sun.

Citing a “structural expert,” Wilder said the porch was structurally sound and that the cause of the collapse was “weight overload.” From eyewitness testimony, staff at Pam Johnston Apartments have estimated that there were more than 50 people “crammed shoulder to shoulder” on the 12 ft. by 12 ft. porch.

“All of the lumber and supporting structure were inspected and there was no evidence of rot or decay,” Wilder wrote. “In fact, the fractures of the floor joists splintered in a fashion which is indicative of overstress from excessive weight.”

Despite the collapse, Wilder ensured tenants that the house had been fully approved for occupancy by the City of Ithaca and had even undergone a major structural reinforcement this summer during a “high quality, major renovation of house.”

“As each of the three apartments in the building were completed, the building department inspected all of this work,” he wrote. “During each of these phases, the inspector has been to the building on multiple occasions.”

The porch is being rebuilt; it is expected to be fully operational by Thursday.