Strong winds are believed to have brought down the five storey scaffold at The Royal Beach Hotel.
The scaffold was in place for the hotel to be repainted.
Hampshire Police said no-one was in the vehicles when the scaffolding fell and there were no injuries.
Driver Barry Fleming, who owned one of the cars crushed by the falling scaffolding, told the BBC: “Thank goodness nobody was killed, that’s the main thing.
“But I’m a bit upset about the car. I haven’t been allowed to get under there to have a good look but I think it’s a write-off.”