I feel really proud of myself for getting a internal staircase built in my firestation base

Steps that I took:

• Built a half-staircase on the ground floor

• Used a grappling hook and dragged equipment for another half-staircase directly above onto the roof

• Used a sledge hammer to destroy the half stair on the roof, which left a wooden floor tile

• Used sledge hammer to destroy wooden floor tile on the roof

• This leaves a dirt tile , which I brought the tools to dig down with

• When finished, left with a staircase on top, and a ladder on the ground floor

I am sure you can use any object that overwrites the roof tile to achieve the dirt tile, hope anyone that plans to build on more than one z-level finds it helpful