sandstone basement stabilization: roughcasting or sealants?
I have a home built in the 1880's in Western PA with a sandstone wall basement with parts that have been parged and others that have painted over with a white material (drylock?) and parts that were either left alone or the white coating has disintegrated. All sometime before I bought the house 5 years ago. A french drain system was installed 4 years ago. I have had 2 basement waterproofing agencies out for suggestions for moisture control and to help stabilize the walls. There is sediment from the walls on the ground and areas will crumble when touched. There is an active water leak entering from the outside that we are trying to find. The floor...well is either thin concrete or another absorbent material. We are not looking to change that
We will be addressing the exterior issues: 1. the above ground basement needs repointing and is also crumbling; we are going to have to regrade around the house and replace the pavement that is cracked and sloping; AND see if there is another source of water entry. Should the exposed above ground basement walls then also be sealed?
After that, what seems the most appropriate to decrease the degradation of the walls? The walls are crumbling even where there is not obvious water infiltration. One company has suggested thurosealing and the other rough casting.
Our goal is really just for stabilization/decrease the crumbling and moisture/mold control. The space would be used for storage.
The basement spans the entire length and width of the house. Each company has made it a point to say that it is a "big basement." Perhaps to emphasize it is a big job.
I was unable to upload photos, but can try again if that would be helpful.
I look forward to your advice