The timer is supposedly random and the info I was given was that houses can go back on sale at any point between 30 minutes up to 24 hours after being demolished. But like 100% of the houses I've sat and waited for ended up falling in the long end of it. I've never seen the random timer stop under five hours, and many hit 15+. I honestly wish the random timer was shorter, even if it meant that I would have less of a chance to buy it. Losing it to someone who clicked faster doesn't feel as bad as not even getting a chance because you couldn't sit around the placard 24/7 until it became available for sale.