Water in crawlspace

Not sure if this is normal or not so I thought I would throw it out there and see what the experts said.

I went into my crawlspace this morning to look for my spare tiles. While poking around I noticed that there was a lot of condensation on the underside of the plastic floor liner. I then notice that the sealed plastic mattress bag that I keep my camping gear in also had a lot of condensation on the inside. I took the gear out and found some of it to be rather damp, no visible mold. I then pulled some of the plastic liner back in a few areas and discovered that there are actually a few small puddles. My question is, is this normal after a very wet late summer/early fall? I am in south/central CO and while my area did not get the floods that northern CO got we did get about 5" in 3-4 days. I can post pics if needed.

Pictures are always helpful. Is this the first time you've noticed this?

Very poor place to store anything.
Working gutters.
No mulch piled up against the foundation.
No flower beds forming ponds.
Grade that runs away from the foundation.
Foundation vents.

If you raise the grade where those low spots are with fill dirt there should not be any standing water.
You may even need a drain tile and a sump pump.
Moisture under the house is not a good thing.
Termites and insects love it, and it will cause mold and fungus which can eat the cellulose holding the wood fibers together.

joecaption said:

Very poor place to store anything.
Working gutters.
No mulch piled up against the foundation.
No flower beds forming ponds.
Grade that runs away from the foundation.
Foundation vents.

If you raise the grade where those low spots are with fill dirt there should not be any standing water.
You may even need a drain tile and a sump pump.
Moisture under the house is not a good thing.
Termites and insects love it, and it will cause mold and fungus which can eat the cellulose holding the wood fibers together.

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Upon further investigation the puddles are actually on top of the plastic liner, not under it as previously stated. The plastic is clear and it looked like the plastic was lying on top of a puddle, as I started to pulled back the plastic I could see that the water was on top and not underneath. The dirt under the liner is moist but not muddy. Could the water come up through the ground and condense through the plastic to form a puddle in a low spot on the plastic? Seems odd to me but I have no idea. After discovering the water on the plastic I looked for leaking pipes but none show any signs of having leaked, there are only 2 water pipes.

I've not been able to get any decent pics on my phone but will get out the camera this evening if I can. But, I wanted to answer the questions posed thus far, if they even still apply based on new info.

The gutters are working fine, no leaks or clogs.
There is no mulch around the foundation. We do have 12" pavestones lining the foundation. After those is the grass.
The grade is pretty steep, maybe 10 degrees or so. The crawl space is under half the house, the other half is an unfinished walk out basement. No water has been seen in the basement side.
There is one vent in the crawl space, I'm guessing that is what you mean by foundation vent?

The grade in the crawl space is basically 0 degrees but certainly not flat, hope that makes sense.

If I can't figure this out, what type of contractor should I call in to look at it? Would a home inspector, GC, other?

If you have had a summer with high humidy, this could be just condensation, or it could be ground water as Joe suggested. But you always want to check the not so obvious like leeky plumbing and roof leeks. A house that has a real good vapour barrier can move water from the attic to crawlspace without ever doing anything inside the house. Exposed cold water pipe can cause a lot of condensation. When you have a vented crawl space it should be cross vented so wind can help dry stuff out the vents should be something like 1/150 of the square feet of the crawl space.
And welcome to the site.

The temperature and humidity inside a crawl space stays fairly steady.
The temperature and humidity outside goes up and down as days and nights pass.
What you have is warm wet air entering the crawl space and the water vapor condensing on the colder plastic sheet.
This does no harm, the water will turn back into water vapor and disappear.

Unless your crawl space is sealed off and conditioned with a dehumidifier, humidity will infiltrate and then condense on the items sitting on the cold floor. And if the bags are not air tight, the humidity will get inside them as well. The moisture most likely came from the air. The solution is to seal off this space from the outside air and run a dehumidifier - no need for a contractor. And it does not hurt to provide an insulating layer between your items and the cold floor and walls. For example, put items up on pallets. Or if up against the wall, put a board in between. And even if you get moisture through the walls and floor, putting items up off the floor and walls and sealing the space off and dehumidifying will protect your items.

Drywallinfo said:

Unless your crawl space is sealed off and conditioned with a dehumidifier, humidity will infiltrate and then condense on the items sitting on the cold floor. And if the bags are not air tight, the humidity will get inside them as well. The moisture most likely came from the air. The solution is to seal off this space from the outside air and run a dehumidifier - no need for a contractor. And it does not hurt to provide an insulating layer between your items and the cold floor and walls. For example, put items up on pallets. Or if up against the wall, put a board in between. And even if you get moisture through the walls and floor, putting items up off the floor and walls and sealing the space off and dehumidifying will protect your items.

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Molecules of air are much bigger than those of water vapor. Lots of things are air tight, but not water vapor tight.

It is probably true to say that, at this time there is no such thing as a water vapor proof crawl space, or home for that matter.

To have a water vapor proof crawl space, the walls, ceiling and floor would need to be lined with water vapor proof plastic sheet, with welded or taped seams. No one has ever done this. What would be the point?

Crawl space walls, floors and ceilings are made of products that are not water vapor proof.

jb1023 said:

If I can't figure this out, what type of contractor should I call in to look at it? Would a home inspector, GC, other?

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It's be best to call a "Leaky Squeaky" contractor since it sounds like there is a leak

Jb, welcome to the forums!

As your crawl is connected to the basement, the walls should be insulated (as existing) AND a house-air supply should be installed. This will move warm air currents around in the area to remove moisture so it won't condense on the cold plastic/earth. OR--- close it off from the basement air, and ventilate it per minimum code requirements. Once moisture condenses on plastic- you have a moisture problem there, that will only get worse as the temps get colder. Expect condensation on the wood joist framing/wood deck sheathing boards/ply/OSB and mildew (mold). Crawlspace air RH tracks outside RH- this is where your water is from- not a leak; http://www.smartvent.net/docs/crawlspacestudy.pdf

Condition the basement /crawl with house air supply and numerous choices of exhaust; http://www.buildingscience.com/docu...crawlspace-construction-performance-and-codes

If the basement is unfinished, you could insulate the crawl/basement floor/water supply lines; http://www.google.com/url?sa=t&rct=...oqkTtt4lI6P7ObQ&bvm=bv.56146854,d.cGE&cad=rja

Though for a premium install, add foil-faced foam board (PIC) - air sealed and leave a gap at fibrous insulation/floor sheathing; http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/ Check with local AHJ per code left uncovered.

Fibrous insulation is rated for R-value in a six-sided chamber, leaving a side off (attic/crawlspace application) takes a hit in the R-value, exposed to air movement; pp.12;http://www.energystar.gov/ia/partners/bldrs_lenders_raters/downloads/TBC_Guide_062507.pdf

In a heating climate, the pressure drive (air/moisture) is usually upwards, any crawlspace air leaks find their way to the attic (stack effect) due to pressure/temperature differences (natural/mechanical); http://www.wag-aic.org/1999/WAG_99_baker.pdf

First; insulate/air seal the rim joists, a major contributor of air infiltration/exfiltration due to the seasonal shrinkage/expansion of older solid wood rim joists (R-1.25 per inch); http://www.buildingscience.com/documents/insights/bsi-023-wood-is-good-but-strange/

http://www.buildingscience.com/docu...joist/files/bscinfo_408_critical_seal_rev.pdf

Gary

There is no point in insulating crawl space walls, or in adding heat.

The crawl space is not heated and it is outside the home comfort zone, therefore, whatever happens there will not effect the home temperature or humidity once the house floor is sealed and insulated.

Bringing warm air into the crawl space is pointless, if the idea is to raise the crawl space air temperature,to enable it to hold more water vapor and to stop condensation. All this does is to raise the cost of heating a home, at a time when we are trying to save money, the Earth and carbon emissions.

It is perfectly normal for condensation to form on a cold surface that is below "dew point" it happens every day all over the world. Water vapor always moves towards a cold area and/or a cold surface to condense, Condensation forming on a plastic sheet does no harm.

Keep in mind that as the air gets colder as we move into winter, the airs ability to hold moisture decreases, there is less water in the air, once the temperature drops to 40f the air is almost dry, once it reaches freezing the air is dry.

Water vapor always moves towards the coldest area/surface, because of the heat leakage from the home, the wood surfaces that are part of the home are subject to heating by radiation and conduction, as long as the home is heated moisture/water vapor will not enter the structure of the wood.

As mentioned previously the structure of a crawl space is not water vapor proof, therefore as warm wet air arrives outside, and where and if, the temperature in the crawl space is lower, then the water vapor will pass through the various holes in the crawl space walls, floor, ceiling enter the crawl space and condense on the coldest surface, most likely the plastic sheet.