Conflicting Expert Opinions for My Humid Basement

13 years ago

Hello everyone. We bought a house with a very humid basement in Central, PA. We were typically at 80-90% humidity without a dehumidifier in the summer. A portable dehumidifier would bring it down to 60% running nearly constantly. The house has supposedly never had water in the basement. It's partially (80%) finished.

The back of the house is level for about 20 feet until the property slopes up at about 15-20% grade for an acre. The front of the house continues the grade down, down, down. So, we're on a hill.

A "wet basement" pro came out and said that our sump pump hole from 1974 needed to be improved with a closed system sump pump (we have nothing now) that would suck out ground water from our gravel base under the concrete slab. In addition, he recommended we buy a whole house dehumidifier (not ducted into the furnace) for the basement. Total cost $2500.

An energy auditor came out and said that sealing up the house is going to trap moisture and that we need to regrade the rear of our house to have a slight slope down meeting the opposite slope in a drain canal that would wrap to the side of the house.

He felt that water was likely accumulating on the rear basement wall. He did not agree with the basement guy who felt that the water was coming up from the stone base. He said we would be fine with our portable dehumidifier.

Honestly, I don't know who to believe. Both makes sense. Both are quite a bit of money to remedy. One will mess up my landscaping. However, the energy auditor didn't seem to understand the concept of a whole house dehumidifier beyond the ducted kind. They are also more energy efficient.

Comments (3)

worthy
13 years ago
Wet and humid are two different things.

If I left all my basement windows open in the summer the air would be humid down there, but there wouldn't be any liquid water.

Basement windows should all be closed in the summer. If that's the case and your portable dehumidifier already brings down rh to 60%, you're almost down sufficiently to avoid moisture problems. You may need nothing more than a larger capacity dehumidifier. Or just an additional one.

Whole house dehumidifiers are more often used in really hot humid climates. Think New Orleans.

Regrading to avoid future water leakage problems is always a good idea. But I don't think it will affect your humidity concerns.
jtabler
Original Author
13 years ago
Thanks. I see where they were going with this. I think I'm going to get a Santa Fe RX whole house dehumidifier. Having read all the information, it's definitely overkill for 70% of the year, but those humid days from June until September are mold growth periods if I can't get the humidity below 50% consistently. I was planning on keeping a very valuable hobby collection down there -- heavy humidity is not its friend!
worthy
13 years ago
I'd try the cheapest approach first--another or higher-capacity stand-alone dehumidifier. As Building Science points out, it can do the job for a fraction of the price of whole house systems. And they're talking about homes in the Deep South.

Here is a link that might be useful: Supplemental Humidity Control for Hot Humid Climates