Hi all, first post.

I own a pier and beam house and the floor is 2x5 pine tounge and grove. The pine boards are installed over the flooring joists with no plywood or other subflooring. When they installed the french doors they set the bottom sill on top of the pine boards.

My question is: I have had some problems with water ingress at this door and want to improve the water resistance. If need be I can remove the door and reinstall but I need to know what the proper method would be. I have included a sketch up for reference.

If anything, it will be easier to remove your doors as there is no finished flooring that is butted up against the threshold. If needed, you can remove your door just like any other - remove trim, cut or remove any nails or screws holding the jamb in place and remove the door.

Beyond that, it's a matter of why it's leaking and what to do about it. It could be you can solve your leak simply by adding a bead of silicon caulk to the outside threshold. Or, if there was never any caulk under the threshold or it's dried out, then you may need to remove the door just son you can reseal under the threshold with silicon.

http://www.epa.gov/iaplus01/te...al/moisture/1_6.html

Most of the time it's because someone built the deck, stoop, patio level with the threshold on the door. That's 100% sure way to get water in the house. It needed to be at least 4" below the threshold.
If someone did not take the time to flash it correctly, or whatever they used under the threshold to support is sticking out behond the threshold. It sticks out to far it acts like a funnel to direct water under it and can do major damage.

If there's a way to angle whatever is on the outside of the door to help deflect the water away from it, that might be easier then taking the door off and re-doing the installation.