Crawl Space Dehumidifier due to Dampness
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  1. #1
    Join Date
    Sep 2001
    Location
    NJ
    Posts
    22

    Crawl Space Dehumidifier due to Dampness

    yo,
    Due to recent storms and hurricane Irene our crawl space (CS) is reeking & damp.
    Last time this happened, in 30+ years, was 2 yrs ago & it was due to severe storms & rainfall was about 6 inches. Two large box fans dried it out. They are running now as well as a small vent size fan jury-rigged outside (trying to extract CS air).

    We are in Southern NJ. All sand down below well, that is 125' deep

    CS is 25' x 55' w/ sand floor, 5' tall

    we have 3 crawl space vents; 9. in. x 18 in each

    with un-insulated HVAC ducting; and piping attached to overhd (joists)

    also contains well pump

    No plastic over sand

    no insulation on block side walls or overhead

    so CS is not climate controlled

    Caused by high ground water & humidity; no leaks in block sidewall or from plumbing, washer, etc.

    We feel that since the cs has been dry for 30 + years except for when we were innudated by the heavy rains 2 yrs ago and last week, we may need just a Dehumidifier and let the plastic over sand & sidewall insulation off; because, we have close friends here that had it done, but incorrectly & @ relatively high cost by some of the largest national restoration companies; and this work has caused huge issues.

    Our son had one company that wanted $1000.00 last year just to test for mold in his open basement. They wouldn't do anything until they were assured that mold was not present.

    We know there is no mold down there.

    An online chat w/ http://www.allergybuyersclub.com rep was lengthy and the rep suggested Ebac CS60 Dehumidifier based on CS size, etc.

    Any opinions on this unit?

    We may go with a CS Dehumidifier w/pump to begin with; the plastic over sand floor & the side wall insulation is dependent upon local company reviews and chats with recent customers.

    Be well and again, thanks to BaldLoonie & others here who helped us when we upgraded the HVAC!

  2. #2
    Join Date
    Jun 2003
    Location
    Madison, WI/Cape Coral, FL
    Posts
    6,233
    Plastic on earth is important because of an endless supply of moisture wicking up. Vents to the outside are great when the outside air is dry and the moisture from the earth is present. After covering the earth with plastic and during times of high outdoor dew points, vents closed stops the endless spring/summer/fall outdoor moisture. Get a good dehumidifier like the Santa Fe Compact or Advance. The one you mentioned is a poor performer. A good dehumidifier will help keep you home dry also. Mold is growing in your crawlspace as we speak. Get to <55%RH asap.
    Regards TB
    Bear Rules: Keep our home <50% RH summer, controls mites/mold and very comfortable.
    Provide 60-100 cfm of fresh air when occupied to purge indoor pollutants and keep window dry during cold weather. T-stat setup/setback +8 hrs. saves energy
    Use +Merv 10 air filter. -Don't forget the "Golden Rule"

  3. #3
    Join Date
    Sep 2001
    Location
    NJ
    Posts
    22
    yo TB!
    TY!
    Will add the Santa Fe Model Number – 4029900
    to top of List!
    Am awaiting Mold test by NAHI to be done in 2 hours by local NAHI member

  4. #4
    Join Date
    Sep 2001
    Location
    NJ
    Posts
    22
    yo,
    UPDATE;
    Inspector spent much time in CS; No visible mold exc for some "light haze on joists".
    btw, I know him well since he lives about 1/3 mile away and has been in Home Inspection for over 26 years.

    Took air samples in CS and outside home; and swabs inside.
    Awaiting results by Monday or Tuesday.

    We will place barrier on sand
    May need 2 dehumidifiers?
    I failed to mention that the CS was divided! I have not been down there since Navy replaced some body parts for me (under warranty of course!)

    Insp. said 2 because CS is 25' W & 55' L WITH a concrete block wall right down center along length (for a better idea, the CS is split into two spaces; each is 12' W by 55' L); block wall serves as load bearing for floor joists above

    There is one access to other CS area, about 2' H x 2'W

    There are openings along top of block divider wall between joists; avg is 9" H x 12" W

    So, the Inspector told me to relax, don't worry about what size dehumidifer(s) to buy until the test results come - BUT, I plan, plan, and plan and have to get er done, day or night; with or without artillery support and so on.

    dehumidifer(s) must have ability to discharge via a condensation pump (to deep sink in laundry room above)
    & automatically restarts following a loss of power since the 'lektric company diverts power to Casinos (about 3 x WK)

    Thinking or guessing that the one Santa Fe Compact dehumidifier Model 4029900 mounted in one side of CS and box fan mounted in access betwen both spaces will suffice?
    or use their duct work kit?
    Thanks again

  5. #5
    Join Date
    Mar 2001
    Location
    Washington DC
    Posts
    73
    Plastic on the ground makes sense. Control exterior water: make sure drainage is all set to get water away from the house. Put dehumidifiers in the space, close the vents, insulate the side walls... you have uninsulated ducts in an unconditioned space in a climate of over 4000 heating degree days. Make it a closed, insulated, semi-conditioned (dehumidified) crawlspace, and the performance of your house will improve AND the moisture issues will be resolved. Remember to check it a few times a year, especially during humid seasons, since dehumidifiers (and particularly the humidistats that control them) can be fluky.

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