If the stairs are located in the center of the house, it will seem to "usurp the role of the master." Stairs are used to walk far away, and people go up and down, making this place noisy and uneasy, which not only wastes the precious area of "holes", but also shows disrespect for "trampling", and naturally will not bring good luck to the owner.
The so-called "center" here does not refer to the area where you started to step into the stairs on the first floor, but refers to the position where you climbed to the second floor or the platform on the third and fourth floors. In other words, make sure this place is the center of the first floor. The point is here. Even if you step into the stairs, or the center of the house is below half of the stairs, there will be no problem.