trouble-shooting water-soaked crawlspace insualtion

[ncstan]

I noticed my carpet was moist in a spot in my house. So I knew something was not right. I went into my crawlspace and saw where the insulation was soaked especially near the center of the house near where plumbing pipes are. There were some small puddles of water. In the past I have had a leak in my condensation line from my air conditioner that caused the same problems. I first went to check my water meter to see if there was a property-side leak in my plumbing system...no indication of that. There was no smell to indicate drainage leak from sewer discharge. Plus, most of the water was in the insulation...just some water puddle. I heard no dripping. I called the on-call plumber and he suggested it was more likely the AC based on the conditions I described. I had the AC repair come and they determined it was not the condensation line or refrigeration line. He told me that he didn't think it was plumbing or Id have a lot more water in the crawlspace and would have noticed wet areas in areas of the house where plumbing is.

He told me it was probably moisture build-up from humidity. Since it was in the center of the crawlspace and was dry near the crawlspace entrance. Does this sound plausible? The insulation is soaked, I have foundation vents and plastic on the crawlspace soil floor.

Any ideas on what is going on? remedies??

[Harry K]

Yes, pull out the soaked insulation for starters. It is now useless, actually will damage whatever it is in contact with. Get rid of it then find out where the water is coming from. I find it highly unlikely that it is from humidity. It would have to be almost a sauna in order to 'soak' insulation.

Harry K

[ncstan]

Would it be a good idea to have the plumber look...I dont know much at all about home repair.

[ncstan]

Im in North Carolina, it is presently 90 degrees F with 60% humidity. There has been highs in the 90s with lots of rain past days.

[Pop]

Get the insulation pulled out, locate the source of the water, and fix it. If the handyman can't handle it, then it's time for the big bucks for a specialist. It's highly likely a general contractor can handle that.

Assuming no one buried a dryer vent etc. in there somewhere:

My assumption is that you have a plumbing leak (supply or drain) which is running along pipes/beams/joists to a low spot where it finally falls thru into the insulation. To trace it might mean removing more insulation to see just where it's coming from and the source could be a long ways from where the water is being found.

HTH, Pop

[Paul Franklin]

As others have said, pull out all the wet insulation and rule out plumbing leaks and the A/C drain.

But it certainly is possilble for the condition you describe to be caused by moisure in the air. Because you are running the A/C, the floor is cool. Warm moist air rising in the crawlspace, if not sealed out by a perfect vapor barrier, will condense on the underside of the cool flooring. Note: this does not mean you should staple plastic to the underside of the joists, this will just cause the problem to switch seasons.

There was an excellent article in the Journal of Light Construction sometime in the last year or two about ways to deal with this. Don't know if it's available online or not. They had lots of pictures of houses with rotted framing where the only source of moisture was the crawlspace air.

A first step is to make sure the plastic covering the crawlspace floor is sealed to the walls, all the seams are overlapped and taped, and there are no tears or uncovered areas. If there is any moisture in the ground, you want to keep it there. Likewise, if moisure is wicking through the crawlspace walls, you need to fix that.

But even with those steps, if you live in an area where the humidity is high, there can be enough water in the air to cause the problem you are seeing.

HTH,

Paul

[ncstan]

Were the effects seen at the same time as the rain or was it delayed a day.

I did have a new roof put on in November

[EXT]

Had a similar problem a few years ago. I was having water drip into my finished basement through an access door in the ceiling. We matched the dripping to times of rain and had eliminated all plumbing leaks, as a bathroom was very near the access door.

The final source of the water was a split in a fibreglass shingle. The water followed the plywood roof sheathing to the next seam, dripped onto the insulation and down to the ceiling vapour barrier. It then followed an opening in the vapour barrier where a plumbing vent pipe went down within a wall. The vent pipe made a 90 degree turn just above the access door in the basement. The water followed the pipe down to the elbow and then dripped through the door edges. This all took about 3 days of rainy weather to trace the source of the water.

On the first dry day, a tube of silicone caulk plugged the split (along with a number of others that were starting to crack) and elimininated any more water gaining access.

Water can come through anywhere. In my opinion soaked insulation would not occur with high humidity, but can be caused by a rain leak, supply or drain plumbing leak or condensation on cold water pipes or condensation lines. Keep looking for the source it is somewhere.

[joe]

similar problem here. the rubber vent pipe gasket where it goes thru the roof and roof flange cracked and when it rained water followed the vent pipe thru the wall to the crawl space flooding an area of the crawl and insulation.

[EXT]

Since it dripped on our heads and onto a carpet it was quickly noticed. The delay in a real bad summer thunderstorm was not delayed much, probably less than an hour. If you just had a new roof you may want to go up there and check it out. It doesn't take much to let some rain in. Mine was a crack less than an inch in length in a shingle hidden inside the space between two tabs which let water trickle through the roof. It was hard to find, but obvious once I found it. I also noticed some other cracks forming. In a new roof there may be a bad flashing or other seal on something that penetrates the roof, or something similar.