Hello,
I am considering purchasing said house in title from my uncle.

What I know:
-built in 1898’ish 1680 sqft. pointed roof with eaves and attic

-not insulated. I’m thinking its a mix of fieldstone some granite. The stones are a reddish brown rust color. The walls I’d guess are at least 12-14″ So it’s stone framing with plaster and lathe. That’s it. House is also 500 ft from the beach, in mostly shade.

-It was pointed with cement. Not sure if the cement was used from the get go or reapplied at some point. (this is what worries me)

So before I dive into this I’m trying to line up my game plan and see if it is worthwhile my questions in regards to options would be two part solution or I’m hoping there may be one solution. let’s see:

I want to stop water from entering the house from the outside. Since there are tenants occupying the house, I haven’t had a chance to get behind any walls. I do know from past tenants that there was mold on the second floor wall and the bottom living room walls were gutted and sheet rocked. The carpenter said there was moisture and rot present.

This would leave me to believe there was water coming through the cracked cement pointing  or some spalling of the stones. if this is the case is repointing way too costly would there be an option to live with the moisture and work from the interior or venting.
The little I know is that you want to be careful with any type of sealing whether it be spray or plastic barriers, since you don’t want to trap any moisture in.

Long story short everytime I do research and find what seems to be a viable solution I then continue to research the subject and plenty of contradicting advice on this solution 
for example I thought closed cell poly spray foam would be the silver bullet, then I read you don’t that especially in stone foundations because of cracks that will be concealed during settling. and and also doesn’t breathe

I’m afraid I’m going to have to address the moisture first and then gut, frame, insulate
I’m concerned that finding and fixing the moisture issue may be too costly. Perhaps I have to gut everything and then look to see exactly where the water is entering?

Any help would be greatly appreciated. Be safe, Jeff