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My ranch home in Ohio was built in 2020. It has a 2300 sq ft unfinished basement with 1 sump.

I want to finish the basement, so I had a few companies review the moisture levels since I noticed the humidity stays high with a dehumidifier running 24/7. Two different companies recommended improved drain tiles and another sump pump. This would cost over $20k.

My basement walls currently have fiberglass that runs about 4 feet from the ceiling, which would cover the frost line of my walls compared to the earth outside. Under that, the wall is bare.

I have decided to build frame the TOP half of my basement wall, leaving the bottom half exposed. I am replacing the fiberglass with rigid foam and using pressure treated wood ramset to the poured concrete wall.

Finishing just the top half will keep the bottom exposed and quickly present any problems that might arise in the future, instead of hiding potentially damaging hydrostatic pressure behind drywall.

With all that said, has anyone every seen anything like this? Any points of failure I should be concerned about.

EDIT - Added More Details

  • Currently we have no moisture in the basement. We are being cautious by exposing the bottom part of the interior walls.

  • In summer, humidity will stand around 55 with a single dehumidifier running 24x7.

  • Externally, the basement walls have damp proofing spray and some type of insulation wrapping the house.

front view side cut out

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    where does the water comes from? how much is the sump pump pumping
    – Traveler
    Nov 8, 2022 at 2:36
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    Why replace fiberglass with foam? Large amounts of foam raises potential fire safety issues. Nov 8, 2022 at 2:48
  • What damp proofing is on the outside of your basement walls? damp proofing spray / damp proofing roll on?
    – Traveler
    Nov 8, 2022 at 4:12
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    Quite common historically in areas prone to flooding to make the whole lower level "finished" with tile, so you can haul the furniture upstairs, endure the flood, and hose/mop out the downstairs. You could adopt a similar approach "halfway" in your basement.
    – Ecnerwal
    Nov 8, 2022 at 18:22
  • 55RH doesn't mean much without your normal basement temperature. 55RH at 10C is a relatively low RH. Do you heat your basement? Nov 27, 2022 at 21:39

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You should do continuous XPS or EPS with taped seams and 2x4 on flat 24" oc on top (top bottom/plates secured to floor/ceiling). Tape the xps/eps joints to prevent convective currents. Use another layer of 1.5" foam in between the 2x4 on flat. I recommend against vapour barrier in the basement allow drying potential through the drywall.

What damp proofing is on the outside of your basement walls? dimple board / damp proofing spray / damp proofing roll on?

What is your RH when your dehumidifier is running / temperature? RH will tend to be high in low temp areas so not too surprising the dehumidifier would run all the time. What is your below grade r-value? do you have exterior insulation on your basement foundation walls?

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  • Hi, I added the details I can to my original post
    – deftoneYo
    Nov 13, 2022 at 16:55

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