I'm amazed by the preparations you make for Halloween. It's a cultural thing for you, indeed. Anyhow, we did make a haunted house back in college during the school fair. We used cardboards from used carton boxes. We just didn't paint them though. We made real artwork out of them by creating layers of cardboards to create 3D impressions.
Since it was a fair, we made use of real people to act as statues that suddenly move and scare the kids. We made some money from it