Advice requested [View all]

The people who owned our condo prior to us were diy'rs of a sort. Mostly of the "I have a cousin who can do that" sort.

They decided to tile the space in front of the door. As it happens, that space is not 100% flat, but it is somewhat flexible. Which means by the time we arrived, most of the tiles were rather cracked.

Recently we decided to rip the tiles up and replace them with.. something. And I finally got around to starting that process. Only to find a spot about 2 inches along and extending 1/2 inch out from the threshold where the underfloor has been water damaged. In actuality, the whole edge shows signs of water damage, with the composite have that telltale swelling that happens when the stuff gets wet. But it appears to be solid, long prior dried. Except for that one little section, which is black and easily poked through. the bottom of the painted wooden threshhold also looks to be black.

Whats my best option for fixing this? Obviously I cant just cover it over. But its a tiny spot, And with no income at the moment, I find it hard to justify the idea of pulling up the flooring around the area to remove the whole subfloor section and replace it all. For a little 1 square inch section.

All I can think is to pull up the door threshold and replace that with a metal one, and hope that theres not worse hidden. Maybe carve out the little damaged section, use some spray foam, since its not a spot where anyone will be stepping, Find some way to seal the join of the threshold to floor and waterproof the subfloor away from that?