We've decided to install a new toilet in our main bathroom, which has also lead to "Well honey while your at it why don't you replace the flooring as well." So here's the task, we currently have Hardwood flooring from our kitchen that runs into the bathroom as well. The boards are perpendicular to the door. I am trying to figure out the best method of cutting a straight line in the doorframe to transition from hardwood to tile. My first thought was a circular saw cut to the correct depth (on wood subfloor) but the saw will obviously come up short when it runs into the doorframe on each side. I'm looking for any suggestions to make a nice clean straight cut for a smooth transition from the wood in the kitchen to the newly installed tile in the bathroom. Thanks everyone!

Hey all, I moved into a place back in March and a couple months in, I decided to get a new couch. After moving the old one, I found a pretty gnarly plank on the floor (and yes someone tried to nail it down). I don’t plant on moving out soon but I would prefer to deal with it sooner than later. Does anyone know 1. What kind of flooring this is, 2. How to repair individual planks and 3. If anyone recognizes this style? Here’s another photo. thanks!