So you think you are all prepared for demo day. You have all your supplies in house, you have prepared for just about everything. Then the demo crew arrives. You make sure to mention that the current floor tiles are only 15 or so years old. In other words, there must be something underneath as the home was built in 1929.
However, I was warned that there might be concrete, and if it is, I can expect a large additional cost for all the extra labor to remove the concrete and add new flooring. So I prayed for no concrete.
And guess what was under the 15 year old tile?