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Discussion Starter · #1 ·
Raised house approx 2000 sq feet raised 3 feet. Subfloor is soaking wet in the summer when the rain and humidity comes along. I ripped out all the insulation because it was holding water up against the subfloor. You can see in pictures it drips off nails and there are water droplets all over the subfloor right now.

I cannot find a leak. There's no smoking gun. I've checked all the windows, pipes, and chimney. The chimney does have a small amount of water leakage around the flu, but not enough to cause the subfloor to be completely saturated like this.

Could a subfloor be this soaked because of the temperature difference inside the home vs outside? We keep the ac around 68-70 and it's been super humid in the 90s outside.

The house was insulated improperly to begin with. Closed cell foam would have been the way to go. I could wait until winter when it's dry, spray with boracare and mold treatment, and dry foam. My concern is: if there is a mystery leak and I foam insulate this winter, that seems like it will cause bigger issues in remediation later. not sure where to go with this
 

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retired framer
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How well did the insulation fit, if air could get to the the subfloor that might cause condensation but I would suspect a leak anywhere with in 15 ft.
 

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How old is the home? Do you have neighbors with similar homes with out the water?

It is possible that the insulation did not have a vapor barrier so it allowed the moisture to collect.
Having the floor cool and the moisture of the out side might be the issue.

The moisture looks like it has been doing this for a long time. More than one season.
 

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Could a subfloor be this soaked because of the temperature difference inside the home vs outside? We keep the ac around 68-70 and it's been super humid in the 90s outside.
Its possible.
If you keep the room at 68 and under the house its 90, lets say the bottom of the subfloor is at 80F. I'm just estimating numbers -- really just guessing what temperature the underside of your subfloor would be. But according to THIS CHART, anything above 75% relative humidity and you are going to have condensation on the underside surface of your subfloor.

You must be in the Southeast -- I couldn't handle 68 F.
 

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Discussion Starter · #6 ·
I'm in Louisiana. 30 year old home. Noone around me has a raised home. It has been doing it likey for 6 years . The previous owner has r30 bag insulation near the subfloor and foam boarding under that. Problem is, the foam boards werent sealed at joints and it just became a pocket for condensation with hot air meeting cold air.

I ripped all that out to at least allow some ventilation.

I've had contractors say they could bring fancy humidity machines to detect moisture and I'm not sure how that would be helpful at this point. It's all soaked and it's all humid.

My plan, I guess, is to change the subfloor where I can, let the rest dry out over the winter, spray boracare and mold preventative, and then spray the whole roof line/chimney with the hose for a few hours. If i don't get any wet spots, I'll dry foam. That's the best plan I can come up with, unless someone suggests otherwise.
 

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Is there a vapor barrier below the floor?
 
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Jim Port may have nailed the nail on the head!
There should have been a 6 Mil, vapor barrer over the ground in that crawl space!
I also see where people cheap out then building a home and have none automatic opening vents, and if they have regular cheap vents there left closed.
 

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It absolutely could be condensation. In the summer my crawlspace humidity pegs out at 99% unless I run a dehumidifier down there. The warm humid air from outside comes in and condenses on all the cool surfaces, that includes your nice air conditioned floor. In my house water would drip from the floor joists and down the walls and almost rusted out one of my gas lines, caught it just in time. A vapor barrier on the ground will help, but any amount of outside air getting under there will cause this dampness.
 

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On the ground, or under the joists? Seems you could still have pretty high humidity under the house, even with a vapor barrier on the ground.
Depends on location, climate, and the condition of the crawlspace. Up here in New England the problem with putting a vapor barrier under the floor joists is that the crawlspace is still cold, so any trace of moisture that makes it past the vapor barrier will get trapped and condense on top of it, soaking the insulation and floor framing.
They always say to put the vapor barrier on the warm side of the insulation, but that's problematic when both sides are cool or when it changes seasonally.
I personally would let the insulation breathe to the crawlspace and aim to dry out the crawlspace as much as possible. Vapor barrier on the ground and up the sides, with a dehumidifier.
 
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