Need Advice!

I have about a 1900 sqft. crawlspace that had 80% humidity with fungi growth. I expected a dehumidifier to be delivered today, so yesterday I prepared the crawlspace and sealed of all openings. Dehumidifier will not be shipped until 5-7 days.

Data log today reads 90.1% and is slowly rising.

Should I open crawlspace door and direct a fan to pull the humid air out, or will that spread more fundi spores around?

I gotta do something.

Call a professional. What do think one dehumidifier is going to do?

I would consider sealing and insulating the perimeter walls and floor area and HVAC conditioning it.

A couple of methods:


You will need to access where the moisture is coming from.

Look at the roof first - Is the gutter system getting the roof run off away from your foundation?

Next your grade - is it away from the house?

You can’t (easily) change the soil composition but that can have an effect.

You can pull outside air through the crawlspace with a fan but if the humidity outside is no less that the humidity in the crawlspace, that becomes a waste of time/resources.

Start with the roof/gutter/grade then get some plastic down. Overlap and seal seams with tape.

One last item I see here in Northern Michigan is high efficiency furnaces discharging condensate into the crawl. In the heating season that can easily be 5 gallons in a 24 hour period. Add a condensate pump or the proper drain to get any condensate out of the crawlspace.

Bradley Toye “CPI”:

Pot calling the kettle.

You’d be surprised what one correctly sized humidifier would do that’s set up right with duct, etc. Where do you get yours, Lowes? Haha

Appreciate everyone’s input. I know all the corrective measures. Just need a temporary solution in get humidity down until the dehumidifier gets here. One fan at access isn’t working, probably because all other areas are sealed off. Hate to open back up a couple of vents to draw in air to circulate. But if that’s my only temporary solution???

Bradley Toye “CPI”:

Pot calling the kettle.

You’d be surprised what one correctly sized dehumidifier would do that’s set up right with duct, etc. Where do you get yours, Lowes? Haha

Do you have central AC? Are your AC ducts in the crawlspace? AC removes humidity. Can you HVAC condition the crawlspace?

Licensed Mold Assessor, Water damage restoration technician WRT-IICRC, Certified Master Inspector, Building Contractor. Any other questions… Do you actually know what one dehumidifier can handle on a 1900sf crawlspace?:roll:

An Air Conditioner IS a dehumidifier.
Do not connect the crawlspace to the HVAC. It is a common code requirement here and I’m making a $$$$ on this issue. Unless you want to become a client, don’t try to fix this yourself when you don’t know what your doing.

A dehumidifier will not address the “source” of the moisture.
When it removes humidity, it pulls a greater volume in through the building. This causes more problems than “Mold”.

OP: why are you so freaked out about a few days of high humidity?

You are freaking out about rh (Relative Humidity).
Do you know what “relative humidity” is?
It has nothing to do with the amount of moisture in the air, as your probably assuming.
This is a measurement that everyone uses that just screws up everyone’s perception of what is happening.
I can tell you why you have a rise with the CS now closed. It most likely has nothing to do with increased moisture (I can only tell you if you give me the right measurements).

Post or send me your data logger information.

If you want to move a large amount of air to facilitate drying, go to your local tool rental shop and rent a high capacity air mover. I would use it to exhaust air from the damp space and open the crawl space vents. Once set up, have a mold remediation contractor out to give you an estimate on the repair and cleanup job. You do not want to tangle with mold if you are not trained to do so. It can really mess up your health.

Also, stop using your A/C.
Turn on the heat.

Also hire an HVAC contractor, weatherization contractor, soil specialist, gutter contractor, storm water contractor, thermographer, and industrial hygienist to further evaluate and repair anything they deem necessary to make money to take their family on vacation this fall.

Experience the real effect of asking a Home Inspector something about your house…