My opinion if the walls have not been painted, I would use Xypex v a paint or sealant.

 

I'll look into that as soon as I see if the walls were painted or not.

Btw, this is one of those questions where I kept wondering if it belonged here or in the "paint" forum. 🤔

 

Water proof anything on the inside of a concrete/block wall is a waste of time.
If you have no water then paint with your choice of paint. If you have water intrusion then fix it from the outside before going any farther.

 

Unpainted block look best if they are first coated with either a block filler or drylok. Just using regular latex paint won't fill in all the pores. I'd rather a block wall look painted than just colored. Below grade I use drylok. Drylok is formulated to be applied over bare masonry [or itself] and not over paint. Drylok is a good insurance policy but ultimately all waterproofing needs to be done on the exterior side!

 

Waterproofing is done outside with gutters, downspout extensions and grading. It also sounds like this may have been done well on your home. Anything on the inside is water mitigation and, IMO, a coat of paint after any water has made its way all the way through is going to accomplish nothing other than to waste your time and money applying it.

 

Well, got the drywall down and the yucky insulation out and the cinder block walls are already painted on the inside. Had a huge rainstorm blow through and no signs of water coming through at all.

Btw, the yucky insulation was due to a previous homeowner insulating the basement by putting up batt insulation, then stapling plastic sheeing over that. Sure enough, over time moisture got trapped between the plastic sheeting and the paper face of the insulation, and mildew found a nice comfy home and food.

So next step is to clean the walls and insulate with XPS sheets.