https://screenrant.com/full-house-two-staircases-plot-hole-explained/

The iconic home of the main characters in Full House notably has two staircases. Here's why this particular detail doesn't make any sense.

The house that we see during the Step By Step show had two sets of stairs and so did the home that was shown during Mary-Kate and Ashley's Full House follow up named Two Of A Kind.

God bless you and the girls always!!!

Holly (a day one fan of them)