Basement Wall

[Petertaylor]

Our 125 year old house has basement walls of limestone. The stone and the mortar are in good shape, but there is a lot of effervescence and sand continually drops to the floor. We sweep up a quart of sand every few weeks. And bugs crawl out of the cracks. 

I want to hand-trowel on a new mortar surface. It won’t get painted as there is always moisture in the stone. So my QUESTION IS:  What kind of mortar?  Do I need to prep the stone with something so the new mortar adheres well?

Thanks for your help. —Peter

[EightFingers]

I had a basement with rubble stone walls and that did the same thing you’re experiencing. My problem was runoff from the roof. I ran pipes from all the downspouts to at least 20 feet from the house. It was a big job but it made a huge difference in the walls. I then scraped out the old mortar and repointed everything.
After that I painted the walls with UGL paint. It held up for many years until I moved.

[BrentDH]

Does this help?

https://www.youtube.com/watch?v=jgU245CbALc

[Petertaylor]

Thanks, Brent, for the YouTube link. It did provide a few hints: use Type S mortar and mix with bonding agent.

[Snipe Hunter]

The biggest causes of basement water intrusion are improper grading and downspouts terminating too close to the foundation and clogged gutters... or no gutters