Re: Interior door is fractured around the kob
You'll want to get a replacement door "blank" -- that is, there are no holes bored for the lockset, and no mortises for the hinge. Use the existing door as a template for lockset placement and hinge mortises.
If the replacement door has an internal bottom rail of sufficient height, you can cut off an inch off the bottom. Or have the guy with the orange aprons do it on their panel saw. On the other hand, you might cut off an inch and discover that you've cut off the entire bottom rail and now you have a gaping hole on the bottom edge of the door. To fix that you'll need to cut a board to appropriate thickness and length to glue in there -- and it's not going to be a stock size.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.