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Crawl Space Humidity Help

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Hello everyone.

Firstly, let me apologize, because this post might be a bit long. I am starting to go crazy trying to figure out what is right and wrong when dealing with high humidity in a crawl space.

I live just outside the Philadelphia, PA area and just purchased my first home in the end of Sept. 2015. Shortly after moving in I installed a couple of wireless thermometer/hygrometers in the crawlspace so I could see what the temp and humidity was during the different seasons. The crawl space is vented btw. During the winter the humidity was very low for most of the time, but would jump up to the 70-80% range for a day or two if it was snowing/raining and humid outside.

Fast forward to this spring and the humidity has been staying in the 75-90% range. There is already a vapor barrier installed but it looks old and worn, plus there are some tears in various spots. I have been in the crawl space myself several times since moving in. I had to insulate my water lines and do a few other various things. I have also gone in there after we have had heavy rain and never have seen standing water on top of the vapor barrier, but there is some water under it.

I have several companies to call to get estimates from, but had the first company out yesterday. The guy didn?t even go into the crawl space, just stuck his head in and looked around for maybe 5 minutes max. He even tells me that he saw water on top of the vapor barrier, but not positive where it is from, possibly from condensation. There is no HVAC at all down there and all pipes are insulated. After all the talking and explanations, I received an estimate for $26,000. Yes, $26K! $11k for a new vapor barrier because the one installed was done ?incorrectly? and $15k for a French drain system. Granted the crawl space is dirty and has some stuff that needs to be cleaned out (old duct work, wood, fallen insulation, etc.) but these prices seem very very high.

I had done a lot of reading before I decided on calling companies for estimates but at this point I am more confused than anything else. So, here are my questions:

1. Should there be any water at all under the vapor barrier? I don?t mean a lot of water, just a small layer of water in a few areas. I know that there will be moisture, but the guy said there should be no water at all.

2. If I do indeed need a French drain, I would assume it should go outside the perimeter of the house and not inside the crawl space. If there is indeed water coming in under the vapor barrier, why would I want to ignore the problem of water coming in by putting the French drain inside versus dealing with the problem at the entry point (be it grading of soil, gutters, etc.)

3. Even with a properly installed vapor barrier, should I still seal the crawl space and install a dehumidifier since we have high humidity all summer long in this area?

4. Lastly, the crawl space is small, maybe about 2.5?-3? high and the entrance is a small window like opening which I doubt a dehumidifier could fit through. Plus there is not electricity in there. Do they make dehumidifier units that can go outside and be vented into the crawl space?

Thank you very much in advance for any help and advice given. I really need some advice from people not trying to make a quick buck and to put my mind to ease.

Ross Wexler

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Sounds like moisture is rising from the earth beneath the house more quickly than the vents can remove it, despite the presence of a vapor barrier.

Seal up the crawl space, install a new sealed vapor barrier, then condition the air in the crawl with a little help from the central heat/cool system. An alternative is to leave the crawl open and add more vents so it can remove enough moisture. This assumes the grounds near the house are graded to drain rainwater (including downspout discharge) away from it.

Marc

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Thanks for the reply Marc.

The downspouts are done very well, taking all water away from the house. I do think there is a grading problem, as well as a cobblestone patio and concrete walkway in the back that have sunken a bit and are angled towards the house.

I also think that there might not be enough vents. I have no clue how many there should be. The house is approximately 1900 sqft and the crawl space covers almost all of the house except for an additional room that was added later I assume. There are a total of 4 vents.

I am probably not going to be able to do everything at once because of money being tight. I am thinking right now to start with getting the vapor barrier replaced and working on the grading. Though the patio and concrete might cost a bit.

Still going to get some pictures.

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The guy gave you a standard pitch without any particular investigation. I'd forget him for the time being, and he costs too much.

It's not a vapor barrier if it's old, worn, and has holes. You need a real vapor barrier, heavy weight scrim reinforced plastic, run up the walls about a foot or more if possible, sealed to the foundation with termination bar and caulk, sealed around all posts, pipes, penetrations, etc., etc. Vapor barrier, with the emphasis on barrier (or retarder as the dweebocracy now insists).

In your perfect iteration, you'd then spray (SPF) foam the foundation walls from the subfloor to lapping it down over the vapor barrier. Depending on several variables, I might want to ventilate the exterior side of the VB to exterior; there are ways to do this that I won't go into, but essentially, you don't want to create a moisture path in the foundation up into the house framing.

Minimize all conditions that might contribute to crawlspace water.....grading, drainage, downspouts, etc. I'm not necessarily convinced you need a full tilt perimeter drain tile, but you probably should put a sump and pump in to keep water tables lower than the crawlspace floor.

No vents. Seal the crawl and condition it like the rest of the house. If you got the previous stuff right, you don't want or need vents; they can create their own problems. Maybe a humidifier, but if you got it all working right, you don't need a humidifier either.

I'd fine tune these recommendations after looking at some pics and considering the variables I can't know on the internet.

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You say the patio does not slope away from the house. Fix that and any other negative grading first. Then remove the vapor barrier that's in there now and let the soil dry out really good before installing another vapor barrier.

Test the home for radon. If it's elevated you should consider mitigation. The radon mitigation system will also help dry out the soil under the house and help control crawlspace humidity levels.

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The only thing about the estimate that surprised me is that he did not add the line... "if you sign today we will give you a big discount". Often followed by something like "we just had a big job cancel and have a crew standing by". Many water-proofing companies through out very high prices and hope for a sucker.

Look into a sealed crawl space system. There are some companies in you area that can do a good drainage system (if needed) and a sealed crawl space for far less than that quote.

One company has a crawl space dehumidifier that will fit into relatively small openings. I also just helped to install a ducted dehumidifier at our church (its the second one I helped install). This last one was an April Aire if I recall. It can be installed remote from the crawl space.

Interior drainage systems are very common in this area. It is usually much more expensive to do an exterior system.

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So, here are my questions:

1. Should there be any water at all under the vapor barrier? I don?t mean a lot of water, just a small layer of water in a few areas. I know that there will be moisture, but the guy said there should be no water at all.

2. If I do indeed need a French drain, I would assume it should go outside the perimeter of the house and not inside the crawl space. If there is indeed water coming in under the vapor barrier, why would I want to ignore the problem of water coming in by putting the French drain inside versus dealing with the problem at the entry point (be it grading of soil, gutters, etc.)

3. Even with a properly installed vapor barrier, should I still seal the crawl space and install a dehumidifier since we have high humidity all summer long in this area?

4. Lastly, the crawl space is small, maybe about 2.5?-3? high and the entrance is a small window like opening which I doubt a dehumidifier could fit through. Plus there is not electricity in there. Do they make dehumidifier units that can go outside and be vented into the crawl space?

1 - yes visible moisture under the vapor barrier is ok. That is why it (the vapor barrier) is there.

2- deal with water entry from improper grading first.

3- Yes, seal the crawl space, a vented crawl space defeats the purpose of the vapor barrier. Dehumidifier may not be necessary but you can always add one later if needed.

4- Yes

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What damage is this humidity doing? Is there mildew or other moisture-related damage occurring in the crawl space? Are the humidity levels in the house elevated? Also, it helps a lot if you give the temperature as well as the relative humidity reading, and include the outdoor readings at the same time.

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We already have two radon systems installed. The house had one already and when we had the home inspection done it was still a bit high, so they sellers had a radon company come out and they added another system on an addition that is on a concrete slab. After that the tests came back way below the accepted level. I actually just ordered two more tests early this week because we wanted to triple check after being in the house for 6-9 months.

Planning on having a landscape architect take a look at the grading. My mom has used him a few times at her house. She apparently had some water in her basement and after getting several quotes in the $18-25K range she called this person and he managed to deal with the water outside the home for about $3K.

As for damage that is being done, I really don't know. There is a good amount of batt insulation that was hanging down, but it could have been like that for years before we purchased the house. I don't know for sure if there is mold growing on the wood, I will take a good look this weekend.

As for the humidity levels. In the house they stay around 50%, but the A/C has also been running for the past couple weeks. Also the past couple of weeks we have had temperatures in the 80-90+ degree range. Most days the humidity outside was 30-50% during the day and 70-90% at night. At the same time the temperature in the crawl space was around 65-68 degrees with the humidity ranging from 80-95%. It would be a little lower during the day then go back up at night.

Now yesterday we had a break in the temperature, it was about 70 degrees and humidity outside was in the 30% range. It was also very nice and breezy. We did get a few sun showers during the day as well. In the crawl space it was about 65 degrees and I was very happy to see that the humidity went down to about 60-65%. This morning it was at 62%.

I am still going to get a good amount of pictures hopefully tomorrow after work and if not then over the weekend.

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Before sealing or insulating anything, check all around especially the exterior walls for rot, mold or termite tubes. Use a narrow slot-type screwdriver to find soft spots. Go all the way into the back corners where nobody has been for years. It will be an adventure, but then you will know what you've got.

I say this because some crawlspace repair people will spray foam insulation right over rotten wood.

What year was the house built and could you describe the structure a bit, concrete, walls, siding?

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Firstly I want to thank everyone for their help, suggestions and advice. I really and truly appreciate it!

Here is the link to the house info on zillow with some pictures of the house as well. Because of the way the land slopes towards the street, I don't think there is any issues in the front or driveway side of the house. I could be wrong of course :)

The house was built in 1953. The original house is all stone, the additions have siding. As for the foundation, when I'm in the crawl space it looks like large cinder blocks maybe? I'm not really sure, but the picture I am going to take should show well enough.

When you say to check the exterior walls, do you mean to dig down to expose part of the foundation or to check above the foundation? I can easily check inside the crawl space as well, but it didn't look like the foundation was rotting from inside.

'edit': Btw, I also ordered a moisture meter and should have it by the end of today or tomorrow. So when I go into the crawl space to get pictures I will be able to see what the moisture content of the wood is.

Thank you again everyone!

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Thanks, Ross, for the pics. I think maybe you should edit your last post and delete that link for personal privacy, but for the time being, it is great.

I think that is stone veneer over a wood frame, but I can stand to be corrected.

There are a couple of concerns I would have. The kitchen has been reno'ed so check to see if that nice range hood might just be stuck up into the attic. Check the roof above the kitchen for a vent. A hose running up to a vent near the ridge is not correct, but better than nothing. White vinyl hose is unacceptable. You should have a metal vent pipe up there with its own vent. This might prevent a future grease fire.

You were describing your crawlspace as being a bit damp. If you need a new vapor barrier, $50 for the poly, plus an afternoon spreading it out. The rest is fluff. A couple of rolls of red construction tape to seal seams.

The moisture in the crawlspace rises as you warm the house, and ends up in the attic. So check your roof sheathing for mold. There should be at least 3 or 4 roof vents near the ridge. Check if air can get in at the soffits.

Also that roof design has no overhang at the gables. Check for moisture or rot along the ends of the building. No need to dig, I am talking about the wood above ground.

Check the concrete block walls for cracks or moisture stains. Use a new LED light.

For water supply pipes you want copper pipes, or new PEX, and check for galvanized iron, which will be at the end of its service life. The iron pipes usually start leaking at the threaded ends, but they can rot out from the inside as well.

What about the Electrical panel? Is it a newer breaker panel?

Your lot has some good slope to it. If water actually accumulates in pools under the house, you need drain pipe all around, the back and side especially, and because of your slope, that pipe can drain to daylight at the base of your lot. No need for a sump pit.

One more thing, I see a downspout in the backyard draining to a stone patio area. That should have a solid buried pipe to carry roof runoff away from the house. Maybe the most common source of crawlspace moisture is water from the roof. Old houses had the downspouts connected to the perimeter drains. We don't do that here anymore, downspouts drain to a solid not perforated 3 or 4" PVC pipe that takes all that rainwater away.

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Hello again everyone. Sorry in advance for the lengthy post.

So I went down into the crawl space today to get some pictures. Unfortunately, I found something that I think might be a much bigger deal than high humidity and this time I have absolutely no idea what to do.

As I was crawling through the space, at one point I ended up putting my hand down in a spot and nearly fell into a "hole" that you will see below. the vapor barrier covering it looked like it was two pieces overlapping each other and weren't even sealed as far as I can tell. I don't think I ripped it when I hand went into it, but I'm not positive.

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I was quite shocking and a bit dumbfounded to say the least. I tried my best to cover the hole back up with the barrier. I continued on through more of the crawl space and noticed an area that the vapor barrier was sinking into and this time had a large rip but was wrapped over itself. Low and behold, another "hole". It isn't that far from the other hole btw. I couldn't really get a good picture of this one because of angle and lack of light.

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At this point I am now freaking out. I got some more pictures and got out as quick as I could. I am no expert in the slightest bit, but they look like sink holes and it looks like there are water channels at the bottom. I didn't have any kind of measuring tape, but they have to be at least 6+ feet deep.

Anyone have a clue what is going on here? And who would I even call? A structural engineer? I am at a complete loss now.

As for rest of the crawl space. I've upload some more pictures below. I also used my new moisture meter and the majority of the wood I tested is ranging from 20-24% moisture, which I know is way too high.

John, thanks for all the suggestions to check for. I checked a few things, but after getting out of the crawl space I just couldn't do any more. FYI, this was a flip house. It was bought by a investment company in a short sale and they basically ripped it apart and rebuilt the innards.

The electrical panel is indeed new. 90% of the wiring is new as well. They moved everything from the crawl space into the attic (HVAC, duct work, electrical)

The hood fan over the stove does indeed have a metal pipe that runs into the attic and out the roof. The vent is it's own and the opening is covered with mesh wire or something so stuff doesn't get in.

I think the water pipes are copper, but I'm not really sure. I insulated them shortly after moving in since they are still in the crawl space.

I checked various spots both inside and outside the crawl space with the screwdriver. Hard as a rock. Didn't go into anything.

And funny thing about the downspout in the back. When we first looked at the house we saw that and kind of scratched our head trying to figure out why that was there. It was the first thing we did after buying the house. We removed that downspout, patched the hole in the gutter, and increased the size of the other downspout that runs into a pipe which goes into the ground and out towards the street.

Again, thanks you all so much. I am trying to calm myself down and be positive that it might not be as bad as I think, but it's not working too well.

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As you can see here the barrier is pulled away from the foam spray. There are many locations where this is happening. I think a lot of damage and movement happened when they were working down there prior to our purchase.

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This is around one of the concrete supports. Again, the barrier wasn't attached to anything.

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There are various spots that have a lot of debris. Almost like crumbled drywall or something. But I don't know why that would be under the floor.

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Here you can see there is definitely moisture/water under the barrier. There are a couple specific corners in the back of the crawl space where I see this.

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The greenish looking crap you see is insulation of some sort that they had stuffed behind one of the vents. Since the rest were open I figured that one should be as well.

Thank you all very much!

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Sinkholes. The cause likely depends on local geographics. In my area, they're a result of ancient steel sewer tanks long covered and forgotten by an addition to the house. Sometimes, it's abandoned, broken sewer or stormwater drain lines.

Marc

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Thanks Marc. That's what I was thinking. Do you know who I would call for something like this? I assume I would need it checked out before I have it filled.

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There's a couple folks here from your general area who might be able to help with that.

Maybe wait for them to chime in.

I wouldn't backfill them before I learned the reason why they're there in the first place. You don't want them coming back.

Marc

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Thanks guys. I'll be checking back probably every hour to see if one of those in my area has posted.

Kurt, who is Kibbel? I tried doing a search but nothing that stands out as a company in my area who would deal with this kind of problem.

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I agree from the first pics it looks like water has flowed under there, but all seems to be dry now. Also on the positive side, the house has stood firm for 60+ years, and the perimeter walls appear to be plumb and stable. Even so, there could be a seasonal spring that fills those holes every winter.

The last hole in your first set of pics looks like it is hand dug, square sides. And there is no water in the bottom of it. Might be an old sump pit or somebody's planned sump pit.

I see a lot of your pics show typical stuff for a 1950's crawl. If the wood is all sound, you can focus on that little creek bed. Good luck.

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The first set of photos is not very clear. From your description and some of the other photos it does look like you have concerns. A structural engineer would be your best choice.

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