.. Since we're being pedantic, the first is a house of cards. A stack of cards can be a deck but a deck is only when it has a complete set of 52 cards. You also don't 'fold' a house of cards, it 'falls' or 'comes down' to denote it's instability. 'folding' is either literally as in creasing the center and making two ends meet or metaphorically as in poker where you just.. Put them aside.
Since you can't fold a house of cards and the other meaning wouldn't make sense, the only possible take away from this sentence is literally folding a stack (but not a deck) of cards. I don't know why you made me do this.