This section of the house is slab on grade. There is a concrete step just in front of the door. The rotted wood riser fits between the house and the concrete step. I'm going to attempt replacing it. I think that the band joist and floor joists are ok. The door threshold itself is firm. When I replace the riser, should I caulk any or all of the highlighted seams? Is there anything else I should do besides attaching the new riser?