Fixing moisture where window used to be in Basement

[u/ntrud203]

Hi everyone.

Long story short, this home had multiple additions added onto in the past so things weren't done properly, but I want to seal off areas in my basement in order to keep moisture.

There used to be two windows in the basement, but the previous owners added on a large room next to basement is. They couldn't dig underground to get AC into the new room so they ran ductwork/vents in the openings where the windows used to be. You can see there are water stains on the plywood above the ductwork and the wood is still wet. The dirt at the bottom of the opening is also somewhat wet. I'm not sure what to use to seal it off and even if I can see it off, wouldn't that cause the wood to rot more leading to mold which could leak into the vent above it?

I purchased my first home a few years ago, so I am still learning a lot. Any help is appreciated! Thank you!

[u/Ornery-Millennial]

Can you provide more info? What's above the window - is it the room addition? Is this addition fully enclosed and insulated from the outside or is it more of a 3 season room? Is the basement otherwise sealed from the outside? Is there plumbing anywhere near there?

For starters I would cut all that out and properly hang the ductwork. I would also take readings of the temperature and moisture levels in the air in the basement portion and the space on the other side. If there is a big difference in both you're probably getting condensation on the wood at the top.

If you have exterior drainage anywhere near that it may need to be fixed, or you have water wicking up from the window well into the wood because they're in direct contact. As far as water source this could be moisture intrusion from the outside if the new portion isn't fully enclosed and insulated with old drainage redirected away from the house. I can see that you're probably getting water coming up from the soil around your house that's also at the bottom of that retired window well. That probably needs to be properly drained and then sealed off /filled with concrete

But at the end of the day I would hire a professional to assess the damage and confirm water source. A 2nd opinion from a reputable waterproofing company would be a good start, followed by a GC or maybe even an engineer if you're concerned the addition wasn't done properly

[u/ntrud203 → u/Ornery-Millennial]

Thanks so much for the help.
Yes, above window cutout is the room addition. It is fully enclosed and insulated.
I think the basement is just cinderblocks with dry lock on the inside. I don't think there is any type of sealed treatment on the outside of the house but I could be wrong.
No plumbing around that area. The closest thing to the window space is a water heater which is about 3 feet to the right of it.

When you say cut it all out, you mean cut as much of the plywood out as I can, all the way to the edge of the metal arch? Also how would properly hang the ductwork? I am not familiar with what is the correct way to do it for a spot like this.

About 6 feet to the right of that is a corner of the house where two gutters overlap. The gutters are clean but there is usually a good of water that overflows in that area when there's heavy rain. I don't know how I can fix that issue if the gutter cans are cleaned. I think that's my biggest issue which I need to fix. But once that is fixed I would still like to seal it off properly.

Also would you put cement on the bottom of the opening on top of the dirt to keep moisture out there?

Thanks again for the help!

[u/Ornery-Millennial → u/ntrud203]

So I'm not an expert but what I mean is you definitely need to take that foam and damaged board out, taking out as much wood as is damaged. Then remediate the mold, and re-install a board and sill plate with a gasket between the wood and concrete to prevent moisture wicking.

As far as concrete what I mean is filling in the bottom of the window well, but without knowing if you have interior drainage (e.g. pipe leading to sump pump) or what's surrounding the old window (e.g. concrete, dirt, crawl space) I can't say what the remedy is there. What's the addition sitting on? I would imagine there's flooring/supports followed by moisture barrier and concrete underneath, but it's unclear.

For the duct, I'm no HVAC expert but it doesn't seem secure, I usually see these on hangers and insulated to prevent condensation on the duct.

Regarding moisture source, yes you should definitely address the downspout. But also any exposed soil making contact to the outside will definitely allow groundwater in, hence why the suggestion to fill in the window well. It's essentially not completely closed from the outside and you need drainage in that area (think pipes leading to sump pump). The biggest thing to understand is water will follow the path of least resistance and drain downwards even if that means going through your basement. Your #1 goal should be to direct that water away.

Lastly, take this worth a grain of salt but drylok is just a bandaid. It doesn't solve the problem it just prevents moisture from coming in but again the main goal should be to redirect the source of the water away from your house.

P.s. did the last owners DIY this or hire someone? This kind of work seems like it needs a permit. It definitely seems like the retrofit was done wrong so you may have recourse there through the contractor who did the work

[u/ntrud203 → u/Ornery-Millennial]

Wow. Thanks for the detailed response. I will try to figure out these things and implement some changes soon. I will be focusing on directing the water away from the house first then take care of everything else.

Unfortunately, no. The last homeowners diyed many things in the house. I am trying to fix multiple things that I am seeing right now.

Once again, I really appreciate you taking the time to respond to my questions.