This is regarding the deck threshold on my trex deck. I was told this was first generation trex. 1950s but I don’t know when deck was added. Threshold/transition to deck from living room is what looks like concrete and hasn’t weathered the years well. I don’t know if it is attached to foundation or how it was created. I would like to know how to redo it. Replace it or at the least smooth and repaint it. I will send more pics if needed. Thanks