Waterproofing a Basement - What to Do When a Mortar Won’t Stay in Place
For the really big cracks, you’re going to need to fill them in with mortar when waterproofing a basement. In some cases, the cracks are so big or irregular that when the mortar dries it instantly falls out. This is no good. To avoid this from happening, you will have to create a dovetail group that runs the entire length of the area where seepage is occurring.
Chip this groove out with care. Then simply fill it with the mortar. You will know if you have done right after the mortar dries. If it doesn’t set properly, just redo it again. Try this method and see if it doesn’t help in preventing water in your basement.