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  1. #1
    Join Date
    Jul 2004
    Posts
    13
    I have been reading this forum for months but have not found the solution to my situation so Please help!!!
    DETAILS ON HOUSE/CRAWL SPACE
    1. Thirty year old house with 5 vents located on the back fifth of the house only.
    2. Crawl space height is about 3 feet where the vents are located & gradually tapers off to about 1 1/2 feet in the back third.
    3. During heavy rains water runs into the crawl space on the back side of the house only. It starts coming in about half way back of the house & only wets about 3-4 feet into the crawl space. I made a small trench under the plastic to channel the water more directly into the sump pump. The sump pump is located just inside the deepest end of the crawl space where the vents & entry to the crawl space is located.
    4. Four mil plastic is on 90% of the ground except for the last part which cannot be gotten to easily even if laying on back & scooting. Plastic recently put on the inside of the brick foundation wall the whole length of the house on the side where the water comes in & earth touches the outside of the brick foundation. I just noticed moisture behind this plastic last week.
    THE PROBLEMS ARE
    1. Last spring during heavy rains & high humidity I noticed insulation sagging close to the exit of the return air duct to our heat pump. I poked a hole in it & water came streaming out. Also had dripping condensation on the rest of the insulation on the return duct & the round duct work toward the vented end of the house. Moisture was sitting on the pink insulation between the floor joists as well.
    2. Occasionally have musty smelling air coming into the house. No mold on coils etc & drains well.
    3. Checked last week & still have condensation dripping from duct work but not as bad but I realize the amount is based on how much humidity is entering through the vents.

    Don't want to close the vents because during heavy rains some of the water running into the crawl space ends up on top of the plastic until the sump pump gets rid of it.


    ..... Advice received from NON HVAC people..........
    1. Tear off all the insulation & leave metal duct work bare allowing the condensation to evaporate faster. Otherwise constant moisture in the insulation COULD CAUSE IT TO MOLD??? But won't this result in more moisture on top of the plastic?
    2. Have vent fans installed in some of the vents to pull out musty humid air out of the crawl space. Or will this just pull more humid air INTO the crawl space through the side vents? If done I'm thinking they should be installed at the END of the house so as not to pull humid air through the side vents. I have temporarily placed a fan in the entrance pulling musty humid air out.
    3. Have all of the duct insulation torn off & replaced with no gaps in insulation.

    > > > > > I have/am cleaning up what mold is on the floor joists. I have lessened the moisture amount with the sump pump & plastic. Now I NEED TO KNOW is there anything else I can do to minimize the moisture problem which may keep the mold from reoccuring.
    I like the idea of the vent fans to help with ventilation so I would like some feedback especially on them. If vent fans are not recommended, what about a crawl space dehumidifier? > > >
    To anyone who reads this & is willing to help this southern belle I thank you. Location is central Kentucky

  2. #2
    Join Date
    Mar 2004
    Location
    Austin, Texas
    Posts
    1,959
    You need profesional help. I don't know anyone in your area so I can't help much. Here is what I can say:

    The plastic needs to be continuiously sealed, cover the entire crawl space, and prevent any moisture from outside the conditioned space from getting in.

    Leaving the insulation off the ducts will work - if you never use the air conditioner. If you want to use the air conditioner, the insulation needs to be cover the entire ducts and be continuously sealed.

    The water needs to be stopped from getting into the crawl space. Without seeing your house I can't say exactly how. I think Building Science (www.buildingscience.com) has the best information on the web on preventing water from getting into the crawl space.

    I prefer unvented crawl spaces - but the water MUST be prevented from entering for them to work. There was some great information on unvented crawlspaces (if it is still on the web) at http://www.energycodes.gov/news/sts/..._summer03.stm.

    I strongly recommend you get professional help. Good luck to you.

  3. #3
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,451
    Originally posted by bedazzle
    I have been reading this forum for months but have not found the solution to my situation so Please help!!!
    DETAILS ON HOUSE/CRAWL SPACE
    1. Thirty year old house with 5 vents located on the back fifth of the house only.
    2. Crawl space height is about 3 feet where the vents are located & gradually tapers off to about 1 1/2 feet in the back third.
    .

    > > > > > I have/am cleaning up what mold is on the floor joists. I have lessened the moisture amount with the sump pump & plastic. Now I NEED TO KNOW is there anything else I can do to minimize the moisture problem which may keep the mold from reoccuring.
    I like the idea of the vent fans to help with ventilation so I would like some feedback especially on them. If vent fans are not recommended, what about a crawl space dehumidifier? > > >
    To anyone who reads this & is willing to help this southern belle I thank you. Location is central Kentucky
    All earth must be covered by plastic. Over trench to encourage drainage to the sump and eliminate standing water after wet times. Standing water must be eliminated 24 hours after flooding or mold will grow. Close all vents to stop humid air from entering the space. Use a 100 pint/day dehumidifier to keep 1,500 sq.ft. space <50%RH. Get a good one like Santa FE with real capacity and efficiency for cool crawlspace conditions. Monitor with a remote %RH meter like from radio shack. Reinsulating is not necessary on ducts or house flour after closing vents. Also suggest regrading outside the home or drain tile to eliminate occasional flooding.

  4. #4
    Join Date
    Jul 2004
    Posts
    13
    Thank you for your time & response.....If we grade the land it will involve removing a concrete patio/ car port, shrubs, removing a big goldfish pond, a big rock garden & railroad ties. The brick foundation on that side of the house is totally covered with dirt about two thirds of the way back. Then it gradually slopes with the brick foundation being exposed about the last 5 feet. The inside ground slopes toward the sump pump also................ I have contacted a crawl space restoration person but I wanted some feedback from the pros before I got him out here.............> > > > > > > If the source of the water entry cannot be determined I guess it would be ok if ALL of the water could be channeled into the sump pump underneath heavy plastic & a dehumidifier added THEN I could close the vents to stop humidity entry ????? < < < < Perhaps a plastic barrier/liner can be placed BETWEEN the dirt & the OUTSIDE foundation brick to stop the water entry. Then drainage can be placed between the dirt & the plastic to carry the water away. There is only about a 3 feet width of ground outside the house to work with, without tearing out all of the above.

    [Edited by bedazzle on 07-07-2004 at 10:25 PM]

  5. #5
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    1) get a 70- 100 pt/da dehumidifier now, close the vents, activate it, use a cheap box fan to circulate the air --
    2) brick is pourious -- so
    2.1 add a ditch to intercept water on the upper side
    2.2 install gutters
    2.3 have concrete cut next to foundation, put in a ditch there of concrete | mortar mix, pvc drain pipe with holes & nylon sock over it
    2.4 use vinyl concrete patching to build a dam up the brick wall 3 -4 inches

    if you suck in outside air having high humidity, the problem is worse. if you can suck in dry air, then the dehum may not be necessary. one can get humidity data from NOAA.gov, or weather.com
    it is best to keep the water away from the foundation, next best is to coat the outside of the foundation against water entry. a combination of both is optimum.
    the relative humidity needs to be under 70% to slow down mold. get a cheap gauge at a reptile store ~$10.
    keep at least 4" foundation exposed in crawl to watch for termites, etc.

  6. #6
    Join Date
    Aug 2001
    Location
    NC
    Posts
    8
    Try this sight for crawlspace information
    http://www.advancedenergy.org/buildi.../crawl_spaces/

  7. #7
    Join Date
    Jul 2004
    Posts
    25
    OK, here's my last 2 cents and them I'm off to bed...

    Now, I'm not a HVAC professional, but I am an individual who has had to deal with some crawspace moisture issues. Two things I've found that might be useful to you:


    1. You need to drain the water away from your foundation with perimeter drains installed about your foundation. One really good company at dealing with this sort of stuff is Olshan. Here's a link:

    http://www.olshanfoundation.com/

    They've got locations in both Arkansas and D.C., as well as other states. Perhaps they'd be willing to travel to you or can recommend help closer to you.


    2. You need more intelligent crawlspace ventilation. Here's a link to a company that produces a microprocessor controlled active ventilation crawlspace vent:

    http://www.smartvent.net/crawlspacevent.htm

    This little baby samples both the air in the crawlspace and the air outside your foundation vent. It then makes a decision as to whether it is better to move outside air in or simply retain the crawlspace air "as is." You basically close all your other vents and the fan on this "Smart Vent" will run to pull a vacuum on the crawlspace when it wants to bring outside air in. Pretty neat concept, actually. Much smarter than the traditional advice of "leave your vents open" or "close your vents up." Basically, there are times when the air outside will help dry your crawlspace and times when it will bring in more moisture instead. This device tries to figure it out based on temperature, barometric pressure, and so forth so that it can do the right thing at the right time.


    Anyway, hope this information helps... good night!

  8. #8
    Join Date
    Jul 2004
    Posts
    13
    I had read about the Smart vent. I will check it out. I am also ordering a dehumidifier tomorrow. If we go with the smart vent I can always take the dehumidifier with us when (if) we build our house with basement....... Don't know if it makes any difference or not but we are almost certain the water source is from a spring. We cannot see any water up next to the house. We have springs pop up all over the place here during long & heavy rains................. Thanks to all for your most helpful information. Have a great week.

    [Edited by bedazzle on 07-11-2004 at 07:49 AM]

  9. #9
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,451
    You need drying when its wet outside. In your climate, the smartvent will never be venting when you need it. Its a great device when you don't need it.

  10. #10
    Join Date
    Jul 2004
    Posts
    25
    Yeah,

    That's why I had the perimeter drains as my first recommendation... you simply must get the ground dried out in order to control the humidity in the crawlspace. My own experience involved lots of rain and water finding its way in around the foundation. Didn't really appear wet outside the foundation, but in the crawlspace there was quite a bit of water/mud. Don't think the previous owner of this place ever looked in their crawlspace much or gave drainage control much thought. Once I closed on the place, I immediately cleaned out the gutters to stop them from over-flowing, put drain spout extensions on all the gutter down-spouts to extend them away from the foundation (to a location that would drain away from the house), installed perimeter drains along the front of the foundation where the slope of the land naturally runs water back toward the house, and re-graded the soil immediately around the foundation to make sure that it was graded away from the house. With these measures the crawlspace slowly dried out (took 3 or 4 months) and has been bone dry ever since. Since these initial measures seem to have worked, I've been dragging my heels on doing the smart vent install. Still eventually intend to install a smart vent though since I live in a high humidity high heat area where simply keeping your vents open all spring/summer/fall and closed in the winter just really doesn't sound like a good idea to me. The other neat thing the smart vent does that generally doesn't get discussed much is that it will attempt to increase crawlspace moisture when it gets too low... such as in the middle of winter. Pretty cool stuff... but you're right, it can only do so much given that it works only with existing air conditions and cannot actively de-humidify/re-humidify.

    As you said, the smart vent is great once you've got the source of extreme moisture problems under control. Now if the moisture is sourced from a spring... well, that's a whole new ball-game that I'm really not sure how to deal with. Perimeter drains might still work if placed around the entire foundation perimeter like what is done when a foundation extends below the water-table. Again, I would still highly recommend contacting a company like Olshan who can provide an expert opinion based many years of experience.

  11. #11
    Check out my website http://www.crawlspacedoctor.com
    I recomend creating a french drainage system to better control the water entering into the crawlspace. Next block off all foundation vents. It is them crucial to install a proper vapor barrier on all the foundation walls and crawlspace ground. Next install one furnace vent in your heating system within the crawlspace to help circulate the air. Make sure there is no other source of moisture ie. leaking pipes, condensation line, broken dryer vent. Your crawlspace will dry in a couple of days and should never have a condensation problem again.

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