FYI a house renovation would be stalled and further investigated if hidden rooms were found off-blueprint. I can't see any child falling into a dumb waiter down into a secret cellar without the room being thoroughly investigated... A door that cannot be opened upstairs is pure bait for any developer too.
There is so much wrong with this show. It should be begging my interest at this point but I'm more committed to seeing if the plot rent widens or just stays there gaping wilfully by the hand of its creator.