^^ I agree with Ritual. Even if you don't have a challenge to offer at that very moment, you can always come back and post one later that evening, or something. We do want to keep it a challenge and avoid just throwing something up from your old photo collection that may not be a hard mode challenge.
I know the house type tying and the floor you speak of... and I honestly didn't try hard enough to get down there, even though I've been in similar underground 'blocked' spaces in the past. Absolutely kicking myself now!! +rep when I can for the challenge... had me stumped for sure.