If our concrete floor cracks, we're doing this to it! It's concrete with liquid gold to fill the cracks! (What the crap who thinks "hmmmm concrete cracked. I'll fill it in with gold!" What even kinda Scrooge mcduck lunatic is this?
For the basement stairs: cabinets, stairs with flip up steps and very narrow stairs. Each step goes up one at a time for each foot. It is sort of spaced so you are putting one foot per step with a steeper step. Very space-saving.