A witness says it happened at a housewarming party. Ten people were standing on the rear porch deck when it suddenly collapsed.
But one partygoer says the porch was not overloaded with people.
"It seemed like, for the size of the porch, it really--there weren't enough people on there for it to be dangerous. It was a really, like, laid back party. There's no music, there's no dancing, there's just people standing talking, and all of a sudden the porch just came down," said Gilad Shanan.
Two people were hospitalized in fair condition. A third person is in serious to critical condition.
Four others were treated at the scene.
Building inspectors plan to visit the porch to try to determine why it collapsed.