Last year I bought a 70yr old house with a French drain installed in the basement. Both my parents and in-laws have had terrible water problems over the years so I was VERY happy to see it.
There are no real problems, but I am concerned because it is an older 'open back' design. There is a gap between the new concrete and the wall from 1 to almost 2 inches along the perimeter of the basement. It seems this would be nice for drainage, but I never get any water that would enter the system through the gap. I've done a little research lately and it seems that nearly all new systems are closed. This would prevent bugs and more importantly in my area - radon, from entering the basement.
Does anyone have DIY suggestions for filling this gap? Does it make sense? My inclination is hydraulic cement, but I am hoping someone else can either back me up or make another suggestion.
The basement will not be finished so the solution does not need to be elegant.
I appreciate any help you can offer and promise to offer up advice in the future (this is my 1st post, but I'm a HUGE fan of TOH). Thank you.