^^^^^

First, analyze.

Then, among a couple of choices, consider.

See Building Science Corp. on basements.

A neighbor spent 20k and did a tyvek wrap.

Now, that's a new one on me!

The biggest proponents of "waterproof" paints are the manufacturers of waterproof paints. Spray-on crystalline waterproofing is another thing entirely. And is now usually a pro only application.

Building on the other comments here, you need to stop the moisture from getting in through the wall...not just try to block it from the inside. I suggest you speak to a couple of companies that specialize in waterproofing foundations. You may need a better drainage system around the house and/or applied waterproofing to the foundation exterior. Do this before you start any interior work.

I live in Maryland, zone 7. I added new downspouts in case it was from the water not draining away. The house is 70 years old and it's brick and block. I think it's condensation from the insulation that touched the concrete cinder blocks. I have several returns but may need to add another one. I bought a new dehumidifier and that seems to be helping. I also have a French drain around the perimeter. There is no water that comes in when it rains. I am trying to monitor that but have seen nothing so far.

If I used the foam board, do I still need to "treat" the cinder blocks? Also, how clean do those blocks need to be? Doesn't the foam board go directly on the cinder blocks? I read if they are not glued on perfectly, it could once again build up condensation like what I am dealing with now.

This house actually has an underground spring. We are very close to Rock Creek Park. There is a high water table on my property.

The combination of high ground water and a porous foundation wall that is probably not waterproofed or insulated means you need to have an experienced waterproofing company look at the basement and make a proposal.

First, get the exterior water under control.

I read if [foam boards] are not glued on perfectly, it could once again build up condensation like what I am dealing with now.

If gluing, use grid pattern glue lines. If using concrete nails or screws, still add glue lines top and bottom. See here.

Well, I have some people here today ripping the rest of the drywall. There is only water from the corners of the basement. I think the water was not exiting the gutters correctly. It's really weird that this is the only place that shows any water damage. This is good news. There is also a place where someone painted waterproof paint and it looks perfect. Wild. I guess the only way to know if something is wrong is by getting to the bare bones of the build.

Okay, more information is revealed. There is one area with a huge amount of mold we just uncovered. I think we should dig out the side of the house their and see what is happening. Question: Is it dangerous to do this with a 70 year old house? I don't want to put too much pressure on the wall. I guess you do it in small sections right?

That is why several of us have said you should talk to a foundation specialist. If it's necessary to waterproof the exterior they will excavate around the outside perimeter and take care of that. I doubt that you will endanger anything by digging there yourself, but I also don't know how informative it will be to a lay person...and it could confuse an examination by a professional if you have it dug up in advance.

Please explain to me how someone paid $20K wrapping a basement in Tyvek when a 9' x 150' roll just cost $150.

6 Rolls will cover the entire outer boundary lines of a football field. That is just $900 plus tax. That leaves around $19,000 in labor..

Man am I in the wrong business..

Well, I am sure there was more involved than just the Tyvek. This was just something she stressed.

Holly, if they dug the entire foundation up and put used Tyvet to act as a water seal. Those people wasted the entire $20K. Tyvet is not suppose to be used below ground level as a water barrier on basements.

Tyvek on basement walls.

Yep, this brilliant advice crops up frequently on the net.

Usually, a corrective reference follows from Building Science Corp. or Martin Holladay. (But not always.)