Carpet to carpet transition and carpet to tile transition

What is the subfloor to both areas? If it is floorboards/wood then 20mm ring shank nails. If it is concrete then use gripfill or fastest to glue the bars down. The bar ideally should be in line UNDER the door (so as not to see it). You just have to butt up the z edge to the tiles, hoping that the tiles have been fitted in mainly a straight line/edge. To cut the bars, either use a hacksaw or a pair of snips (not tin snips).

Always fit door bars when prepping (i.e. when putting down grippers and underlay), and not after fitting carpet. Check the subfloor. If it is floorboards then a 20mm ring shank nail would be ideal, however, if it's concrete then a fast stick grip fill/mastic. Measure the frame of the door or the actual width of the door. Cut the door bar to the measurement using a hacksaw. The door bar should be just inside the room/bathroom/toilet etc so you can’t see it from outside.

Echoing the above. The main objective it to get the the bars directly under the door whatever way they swing. They are installed the same way by snipping and slotting in to architraves. It’s pretty hard to explain in words. YouTube may be you best best to fully understand

Measure and cut door bar with a hacksaw. Check the subfloor to make sure of it can be nailed or needs to be stuck. Job done

Pull the carpet back check the subfloor to make sure it’s suitable for the door bars measure the size of the door way then cut them to size with a hacksaw once you have done that, just pin them with ring shanks and then put the carpet in if you have a stretcher I’d give them a little stretch into the door ways aswell 👍

Very good answer to the question obviously the floor layer who answered the question is a professional

Go on YouTube

The top rated comment unfortunately is wrong you do not but it up to the tile you must make sure it goes over the tile ( Z edge ) as if you but it up you might be able to see a gap once it moves a bit and if you but it you have nothing to stick to it… always make sure you go over so the bar have something to hold on to. Hope this helps.

Measure and cut the bars with steel cutter

I agree with glamour, I always fit door bars when prepping (i.e. when putting down grippers and underlay), and not after fitting carpet. It’s easy because if you have to adjust the door your not getting sawdust all over your new carpet.