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Crawlspace encapsulation estimate -$$$$$$ - Holy cow!

Crawlspace encapsulation estimate -$$$$$$ - Holy cow!

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  #1  
Old 10-26-12, 08:04 AM
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Crawlspace encapsulation estimate -$$$$$$ - Holy cow!

I have had a small moisture problem in my crawlspace recently - I noticed a dark spot coming up under my vinyl floor in the bathroom. We crawled under the house and found that the in one spot at the back of the house, the foundation is wicking up moisture, right up the concrete, to the brick, to the subfloor, and there is mold/mildew growing - after 14 years of living there with absolutely no moisture issues at all. So we will have to pull up the vinyl and replace that subfloor section. But natuarally I want to address the cause of the issue. I called a crawlspace/foundation company and scheduled an inspection (free) to see what the options were. I knew I would have to listen to a sales pitch, but I just wanted to see what they thought about it, and what the choices were.

Obviously, sealing crawlspaces is a very profitable venture. The guy quoted me a $12500 price tag for laying down about 1700 st of 20mil vapor barrier, sealing the vents, and installing a shiny new dehumidifier (with its own GFI outlet of course). I have to admit, it sounds like a good thing to have done, but there is no way that I am paying that kind of money for it. :NO NO NO: I'll look into a DIY project perhaps. Has anyone else had this done? What sort of costs did you experience? I have googled around a bit, and it sounds to me like the companies are raking in the profits on this service.

BUT, the one MAJOR question that I forgot to ask him. The vapor barrier goes up the foundation brick, to within a few inches of the wood (so that the termite guys can inspect and treat). Makes sense. But...if there is condensation going up that concrete foundation, from the ground....exactly how does a vapor barrier, that is running up that concrete, prevent the wicking of that moisture up the brick and into the wood?
 
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  #2  
Old 10-26-12, 08:37 AM
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Where's the moisture coming from? Can you divert water away from the foundation better with grading, gutters and downspout extensions?

You also do not necessarily need to seal the crawlspace but the options are seal it off from the house and vent it to the outside or seal it from the outside and condition the air in it with your HVAC system.
 
  #3  
Old 10-26-12, 12:09 PM
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Thats way hi. We do this all the time for under half of that price. But maybe there is more to it. One thing I have found I never recommend a dehumidifier at first because 99% of the time the VB is keeping the RH down under 50%.
 
  #4  
Old 10-26-12, 12:50 PM
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Hi yardnut, ouch!
Properly done, as airman said, you will probably not need the dehumidifier. Photograph 5 in the link below shows what you should end up with and a space that neat and clean can share the conditioned air from your home.

I have never had to deal with termite inspections under foam, but it is a common practice down south to seal things up and provide removable access at the top when inspection is needed.

The link below is good reading and it provides other links as well.

As for cost, I always like to inquire "how long" and work in a question about "how many guys". If the answer honestly, like 3 guys for two days, then you can do some easy math to judge the labor and even price some of the materials. Once you get them to break it down their profit looks ridiculous and the quote will often go down. When busy, they always start high just in case someone is gullible enough to bite. Get some other quotes or consider the DIY, it really isn't that bad of a job.

Bud

BSI-009: New Light In Crawlspaces — Building Science Information
 
  #5  
Old 10-26-12, 02:10 PM
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Mitch, the moisture is coming from the ground. This area is against the back wall of my house, right where the deck is attached. There is no drainage problem in that specific area...when it rains, that area is not any wetter than any other area. What might be happening is the gutters further down the back side of the house could be dumping water under the deck...where I can't see it. (I already have a thread on that gutter issue...but I was waiting for some rain to see what happens).
 
  #6  
Old 10-26-12, 02:13 PM
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Bud - he told me they could do it in one or 2 days, easy. 1 or 2 guys. So yeah..they are making a LOT of money here. I will look into the DIY. But I am concerned about getting this moisture issue corrected first. I will check out that link....thanks.
 
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Old 10-26-12, 02:28 PM
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The plastic/vapor barrier should get the moisture down for you. As airman said, you could do this yourself.
 
  #8  
Old 10-27-12, 04:54 AM
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I know this thread is about encapsulation, but, I'm skeptical that water would wick up 1- the foundation, then 2- the brick, then 3- migrate to a wet room in the house. Water for the most point flows downhill. The source of the moisture is most likely a leak at the wax ring of the toilet or vanity drain. If everything is wet, then it is an active leak. The fact that is is under the vinyl points almost directly at the toilet as this is where the subfloor and vinyl present an opening for the moisture to get under the vinyl.

I've never heard of water wicking up on that big of a scale on a house that is above grade. Capillary action, or wicking, happens on a small scale (meaning small tubes) and is related to coeficients of friction and other laws of physics that don't match your scenario.
 
  #9  
Old 11-12-12, 05:48 PM
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Czizzi, thanks for your input. I still have not resolved this issue. I have had a couple of people under the house and both felt that the moisture was wicking up from the soil. The dark spot of the vinyl is not right near the toilet...it's a few inches from the back wall. But I have to admit that your suggestion makes a hell of a lot more sense. It's going to be impossible to tell, I guess, until I rip the floor up.
 
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Old 11-13-12, 06:59 AM
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Its time to chase a leak..... Behind the toilet is the drain pipe and vent that services the bathroom. Is there a shower in the bath or is it a half bath? How old is your house?

Are you able to pull the baseboard molding behind the toilet to see if it is wet under it? Under the vinyl is a 1/4" layer of plywood (luan). Its purpose is to provide a smooth surface for the vinyl to set on. The sheetrock should be about 1/2" off the floor which may provide you with a peek as to where the moisture is coming from. You also may be able to lift the edge of the vinyl to get a look under there also. Hopefully it will tell us a story.

You can also request the assistance of a friend who doesn't mind crawling under the house. Have them go to the area beneath the bathroom. Make sure they have enough light to see what is going on. Then flush the toilet several times. Have the person under the house look for leaks or active moisture or a definite wet area. Next fill the vanity sink all the way up with water. Then release the drain so you get a good steady flow of water through the pipes. Repeat this step. If you have a tub do the same with that. Check with your helper after each station to see if they notice anything. Also, while you are in the bathroom keep an eye on the area where you removed the baseboard to see if you see anything topside.

You should be able to yell and the helper will hear you underneath the house or communicate via cell phones. Let us know if you discover anything.
 
  #11  
Old 11-13-12, 06:19 PM
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A simple probe test with a moisture meter in the crawl space can tell you a lot. Poke the joists, rim board and sill plates with the probes to see if the moisture is truly coming up from the ground. I've seen a lot of moist crawl spaces (usually caused by either a malfunctioning sump pump or water table intrusion, combined with lack of ventilation), but none of them caused mold/mildew on floors or subfloors. The one time I did observe mold and even algae growing in a crawl space, it resulted from a major plumbing leak in an interior wall (common to a bathroom/utility room). Home owner mentioned he always wondered why his well pump was always kicking in, even during times when no water was being used (!).

Before I'd spend a nickel on "encapsulating" the crawl space (if you're absolutely sure the water is wicking up the walls), I'd pull a few deck boards off and look at doing some creative drainage with your gutters' downspouts. Or even dump in a load or two of clean fill to raise and reslope the grade, combined with adding some heavy plastic. A lot easier and cheaper than messing with the crawl space, and probably more productive.
 
  #12  
Old 12-16-12, 09:29 PM
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my two cents ...
start looking for the source of this water/leak high - gravity being what it is.
... if the water is travelling uphill - wicking it won't go too far.

from your description it could be originating in the bathroom plumbing, in the junction of your deck with the house (or even higher - unlikely) or it could be wicking up as you suggest.

quite possibly that suggestion is leading to itself as a conclusion ... and of course the sales pitch is confirming it!

if it is wicking it won't go much above the level of the ground outside.
you may be able to correct the problem by
- fixing your downspout/gutter problem (whatever it is, haven't looked),
- making sure that your perimeter drainage is clean and working
- doing as Mitch suggested earlier and altering the grade outside or otherwise diverting water away from the foundation.

keeping water farther away from the house is better than HVac later - much!
 
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