I've seen a couple of houses for sale that are 3 storey detached - both are built on hills so are 2 storey at the front and 3 storey at the back (or vice versa). Apart from the obvious what are the negatives and positives? I'm thinking things like long way down to let the dog out for a wee / make a cuppa in the morning? Taller shadow over the garden? Carrying shopping in from the car to the kitchen? But more square footage / rooms than similar priced 2 storey houses.