Wondering about how far I should pursue cleanup and/or stabilization of loose and crumbling parging in the basement of my 1910 Colonial, possibly including application of Drylock to exclude exterior damp (basement has never had a sump, we have redirected two downspout drains outside which dumped against the foundation, and the plot is fairly well sloped for drainage) before building an interior studwall for a full bathroom. This appears to be the only part of the basement where dampness has occurred for an extended time. Thanks and have a Happy New Year//Dave