My wife and I are about to start work on our basement and actually turn one of the rooms in the house into a room that I can use, imagine that. One challenge, or obstacle really, is that every wall in the basement is knotty pine. Do we need to try sanding down these walls first or is there a good primer that we can put over the pine. Currently, the knotty pine has what looks like a glossy finish over it. Thanks in advance for the help!