Answer:
The color is nonexistent
Step-by-step explanation:
As you did say before, "one story house" I can bravly assume that this isn't a 2 story house. Well, only houses with 2+ stories need stairs (unless you are a madman) so we can state with the information givin, that the stairs color would in fact be, "nonexistent" as the color. This is the same color as "nothing" or maybe the question "Did yu see that?!" when someone is infact tryng to distract you or get away from this colorless conversation.
thank you for your time.