We recently moved in to a wonderful old house whose basement fieldstone walls are in desperate need of repointing.

Initially I just wanted to find a contractor that would repoint the now sand-like mortar. I have a very reputable contractor that wants to waterproof the walls. Waterproofing is not something I necessarily wanted to do.

After almost half a year in the house, the basement seems generally dry - maybe some dampness occurs in the warmer months.

It seems to me by sealing from the inside that this could trap moisture in the walls and cause issues akin to a spalling brick. I definitely don't want to apply a solution that does not have a problem.

Am I right to be concerned about the stability of a sealed foundation?