Home Improvement Expert Danny Lipford

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How to Solve Moisture Problems Under Your Home

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We live in an older home that is raised a couple of feet off the ground with a crawlspace under it. In the past few years, the hardwood flooring in several rooms has started to warp and cup. What could be the problem?-Mary

Hi Mary,

It sounds like you may have excessive moisture and humidity in the crawlspace under your home. Here’s what you can do to correct it:

  • Make sure the ground around your foundation slopes away from the house (1/2″ per foot or more).
  • Divert rainwater run-off from the roof away from the foundation by installing gutters and extending the downspouts so water is diverted beyond the planting beds and out into the yard.
  • Check your air conditioner unit to be sure the AC drain pipe isn’t clogged and extend it if needed to direct condensation water away from the foundation of your home.
  • Inspect the crawlspace under your home. While the soil may be moist, it shouldn’t be saturated or have standing water.
  • Look for any plumbing leaks as well as excessive dampness, mold, and mildew.
  • If mold or mildew are present on the joists or bottom of the subfloor, treat under the house with a product such as Concrobium Mold Control (available at The Home Depot along with a fogger to rent).
  • Clean out any debris and stored items under your house, and fill in any holes or depressions.
  • Cover the entire crawlspace with thick, black plastic sheeting (6 mil or higher). Overlap the seams by a foot or more and run the plastic up the sides of the foundation.
  • For extreme moisture problems, consider taping the seams in the plastic together, block the outside vents, and install a dehumidifier in the crawlspace to remove excess moisture from the air.

Good luck with your project,

Danny

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3 Comments on “How to Solve Moisture Problems Under Your Home”

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  1. Sasha Says:
    October 7th, 2010 at 2:09 am

    One effective way to combat moisture is by the use of desiccants like Silica Gel. These are the same small sachets you find in packaging of various products like electronics, garments, etc. Silica Gel works by absorbing the moisture in its surrounding area. For most moisture challenges, does the job. With small sachets cost less than a dollar, it truly is a cost effective way of protection from moisture.

  2. Gail Butler Says:
    July 30th, 2012 at 7:22 am

    I am having problems with excessive condensation under my home. It is causing mold/mildew underneath my house. The insulation is all wet (I have had this removed). Some of my floors are now bulkling/swelling and in one room, the sheet rock is wet. I have had 2 air-conditioning repairmen come to check my AC unit and they are unable to find anything. I have had a contractor come & check for any leaks, pipes or roof leaks and none are visible. Insurance adjuster has come and says this is condensation but no one is able to find out where it is coming from. This has all happened or at least shown up in the last 2 months. I had renovations done 2 months ago and none of this was present then and it was dry underneath my home. Even though I am planning on getting treatment for the mold and getting new insulation, I still do not know where the problem is. How can I find out-who do I contact for this? I have also asked for a home inspector to come but they don’t handle this type of problem either from what they tell me. I am desperate to find a solution. My house seems to be deteriorating and there isn’t anything I can do to prevent it. Please help.

  3. MIKE H. Says:
    July 30th, 2014 at 3:42 pm

    HAVE PROBLEMS WTH EXCESSIVE MOISTURE UNDER DOUBLEWIDE..HAVE GROUND COVERED WITH 2 LAYERS OF 6 MIL BLK PLASTIC.. HAVE 18 VENTS ALSO HAVE 3FT X 3 FT OPENING WTH DOOR THAT STAYS OPEN IN THE SUMMER..EXCESSIVE MOISTURE MAKES PUDDLES OF WATER ON GROUND UNDER HOME…ONLY DOES THIS WHEN A/C HAS RAN..& BIG WATER DROPLETS FORM ON BELLY-PAPER OR MOISTURE BARRIER….HAD A/C DUCT WORK CHK;D .. COULD NOT FIND ANY PROBLEMS….ANY ADVICE IS APPRECIATED……….MIKE.. THANKS !!!

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