I am refinishing the basement in my 1936 house which has had water infiltration due to exterior factors--bad grading, filled window well, clogged gutters. All of these have been fixed as far as I can tell, but I assume my walls are holding water: the basement has always had a musty odor, there is evidence of efflorescence on the walls and what looks like a tiny stream of water that came down at some point from mid wall. These issues, though, only affect about half of the the basement; the other half looks okay, and the foundation is solid all around. I am considering installing an interior perimeter drain around only the obviously affected area of the basement (which is the same area I am refinishing) as an insurance policy for the refinish work. Is this (1) truly effective? (2) effective enough but shortsighted? or (3) foolish? It seems weird not to take the drain all the way around the perimeter, but the contractor who proposed it obviously thought it made good sense, suggesting that it would also relieve hydrostatic pressure from other areas around the foundation. It's cheaper to do fewer linear feet, of course, but it also spares messing up an already finished bathroom and dealing with the boiler/water heater/washer/dryer which are all right up against the additional walls in tight spaces. Thanks for your thoughts.