The piece of wood along where the bottom of the doorway meets the floor is rotten in parts - as in I can press it in and it's soft. There's a very thin gap underneath between the bottom of the door and the 'threshold' that must have been letting moisture in over since the house was built four years ago. The gap is so thin you can't really see it, but you can see light through it and feel cold air.
My question is, can I just rip the strip out and put a new one it? Is it a straightforward job? The main question is, how do I fix the almost invisible gap? Raise the 'threshold' piece of wood somehow? - get a professional in?
Thanks!