I finished cleaning out the rotted wood on the porch today. When all was said and done, the only damage was confined to a 33″ x 4″ strip along one edge. It strikes me as safer and easier to square-cut the hole and drop a replacement board in than to pull up the remaining 4 foot by 5 foot by 1″ board—especially now that I realize it’s (a) got the railings nailed into it and (b) is tongue-and-groove mated to the adjacent piece of decking.
So it’s off to get my jigsaw to cut the board out and then some nails and I should be done.