sorry, i did not mean to put "Downstairs bedroom" in the post, i have now edited it. Basically, my sisters room is upstairs but in her room is the only entrance to the basement. I dont know for sure, but i suspect there was an entrance to the basement downstairs that she covered up because her room
would have been closest to that supposed entrance. i was on a business trip for a week around the time when we first moved in, and when i came back i saw construction workers leaving the home. when i asked her what it was about she gave me a vague answer that had something to do with something on the patio being broken. but now im pretty sure she hired them to build an entrance to the basement in her room.