Does that reduce/remove the smell? We also were considering replacing all the basement windows so that we could open them up during the summer and air it out (currently none of the windows are operable and a few even buried).

Yes, I do not notice the musty smell.

Patton air circulator, currently using a ~20”, a smaller size might work, depends on your basement.

You may need to fix the windows.

I am the new owner of an older home with a basement. The seller used a de humidifier, it was expensive to use, if your dehumidifier is not working, it may be undersized for your basement.

I live in a CA redwood forest.

I met a local who said he worked on the property, drainage, they moved runoff about 20’ away from the cabin about 5 years ago.

Anyone else have any ideas?! I’m so worried that we’re not going to be able to fix these issues and/or my family may suffer because of them. HELP PLEASE??

What is the level of water in the old dug well? What kind of soil do you have? You could consider the well as a French drain and put a sump pump in it.

" Is it ok to have an open drain of water in the basement?"

Is there water standing in it at all times? If so you will never get rid of the musty smell completely.

@seabornman...there is a considerable amount of water in the well. We’re not sure how deep it goes. We have clay soil. And we did have one person mention that the well could be helping take some of the water that would be going into the basement, but another person tell us that we should fill it in and it might be causing issues...sooo I dunno!

@millworkman...we haven’t completely dried out the basement yet, so there is water in it, but we’re hoping that it does eventually dry out. We may be looking at putting a sump pump in too, just to help with that. I’m reallllly hoping we can get rid of the smell, I’m not sure I can live with it.

The only cellar waterproofing that works is done from the outside. Excavate around the foundation down to the bottom. Coat with sealer and bond a waterproof membrane to the sealer. Lay footer drains in the bottom of the trench below cellar floor level and route to a sump, adding a sump pump. Sump pump discharge downhill of the house.

Add swales to route the surface water around the house. Fill and/or grade so the ground slopes away from the foundation. Good gutters and downspouts, kept clear (clean at least twice a year), that drain downhill of the house.

Unfortunately, all that is expensive. It also works. Anything less is a waste of money.

If that's too much money or effort, your safest and best course is to put the house on the market, and let the next buyer do the necessary work.

Or give up keeping the cellar dry, decide that you just won't use it for anything, and ventilate it well.

Running a fan to reduce the musty smell is going to be less effective than spraying perfume to cover up BO.

The musty smell is coming from rank building materials that have been subjected to moisture and humidity for decades. A fan ain't gonna do nothing.

You need in no particular order:

- Fix gutters and downspouts if needed. Direct water away from house.

- French Drain.

- Waterproof the outside of the basement walls.

Does the basement have a concrete floor?

If so, you'll need to have the floor sealed to prevent moisture from migrating up.

And a de humidifier.

@DavidR I don’t know if we can waterproof from the outside. It’s an old stone foundation and the addition (with only a crawl space underneath) butts right up to the back of the house where we would want to dig. We are fine not using the basement, what’s the best way to ventilate it?

I don't think it's impossible to waterproof a stone foundation. I haven't researched it, and maybe someone else here has experience. My guess is that you'd probably have to parge the stone from the outside with cement or something similar, then add the usual sealer and membrane over that. I suppose you'd have to excavate inside the crawl space to get to that part of the foundation, which doesn't sound like any fun at all.

If you just can't do a proper exterior waterproofing, I'd suggest doing all the other (exterior) steps on the list - gutters, downspouts, grading, swales. That will at least reduce the amount of water entering the cellar.

If it's still too damp, then you need to remedy that. To consider crawl spaces, ventilating them used to be the standard practice. Today there is a trend toward sealing and conditioning them. Personally, I raise an eyebrow at the idea of heating and air conditioning a space that nobody but mice is living in, but who am I to say?

In your case, that's all moot. If your cellar is going to be damp, you have to get rid of the excess humidity somehow.

You can run up a big power bill with multiple dehumidifiers. Others may disagree, but IMO, it's more economical to ventilate the cellar. You can replace your cellar windows with crawl space vents, and make one or two of them exhaust fans. Fans cost around $100-150 each, and use considerably less electricity than dehumidifiers.

I'll be interested to see what others suggest.

The French drain can be routed where the addition is. And the water in the soil will be diverted around the house.

If you decide to excavate the exterior walls to waterproof, You might consider a gunite application on the stone wall. This will provide a smooth surface to apply the waterproofing.

Here's how Dr. Lstiburek, one of the leading building scientists in North America, handled waterproofing his own rubble foundation basement from the inside. Not a simple or inexpensive proposition that may not be economical in your location.

Fans and open windows are not the way to reduce humidity in a basement during the summer.

As noted above, the musty odour is likely embedded in building materials after years of neglect.

I bought a house that was vacant for some time and not cared for in the years leading up to that. My basement had issues something like yours and I know that musty smell. I started by running a dehumidifier which helped with humidity, but the odor remained. Then I bought an air purifier (the ionizer kind) and that made all the difference in killing the odor! I also found a good mason (after a bad mason. lol!) and had necessary repairs done, gutters installed, and buried drains put in to run water away from the house.

ETA: I also had a small addition with a crawlspace at the back which had no insulation. I hired a guy to install insulation under the floor and it made a huge difference in comfort and the heating bill! When the mason dug around for repairs and drainage he also laid plastic on the crawlspace dirt floor.

@worthy wow. That article and the corresponding crawl space one is scary! Literally talking to my husband about selling this house now because I don’t know if we can do something like that. But thank you...it’s good info to know...just wish I knew all of this before we bought this house...I would’ve never considered it.

@party_music50 thank you for your input! That’s making me feel a little better...been filled with anxiety and dread over all of this. We have a baby and I just want to do what’s best for him, my family, so we can live a comfortable and happy life. Did your musty odor go away completely??

A combo of 1&5. Which will likely cost almost as much, or more, than the cost of the house. Who inspected this and advised you that this was a wise purchase?