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Moisture challenges in my basement

christine13 | Posted in General Questions on

My home was built in 1996. Split level, 1040 square feet. No central air or air conditioning.

We have always had moisture issues with our basement. Cool in the basement, on hot days, just as hot upstairs.

Our bedrooms are in the basement, the basement is completely finished however the floor is cement. We thought we sealed it years ago, but apparently not.

We try to control humidity with a dehumidifier however its not economical nor does it work well.

Our bed seem to draw moisture, we have stapled plastic to all our bed frames to protect our beds (box frame), any wood is sealed with kilz 2 to prevent mold. However our blankets,pillows, rugs etc always smell musty. Our basement in general doesn’t smell all that great! So to try deal with the smell the windows are always open – defeating the purpose of a humidifier.

Any suggestions? Some say central air would solve the problem?

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  1. Boro | | #1

    I agree with the above. The dehumidifier is the solution. You may have to purchase a larger size dehumidifier to handle your situation but it will be worth ever penny.
    One important thing to remember is to keep all your windows and vents closed....always! Open only on the rarest occasions.
    This may seem counter intuitive however the constant battle between warm outdoor air and cool basement air will result in condensation and humidity.
    Let the dehumidifier do its job. It may take several days, maybe week(s), but eventually it will dry out.
    Once everything is dry, clean like you've never cleaned before.
    I speak from 9 years experience living in a basement apartment.
    Good Luck!

  2. wjrobinson | | #2

    All you can do is dehumidify and that will be your lowest cost solution.

    Your home could be rebuilt to have less moisture issues but the cost would be tens of thousands IMO which is a bit more than the monthly electric bill for your dehumidifier.

    No one likes my best thoughts when in a situation like this, but, if you look for a home that is better built to buy, and sell what you have... you might end up spending much less than rebuilding what you have.

    To help your dehumidifier out, you could learn here how to do some air sealing yourself to slow the outside humid air from entering your home. Your home most likely is very air leaky. Try taking off one piece of window trim to see how the windows were installed, with fiberglass or spray foam.... See if your electric provider or your state has a program to help improve your home's use of energy. Many states do as much of the funding comes from the Feds.

  3. GBA Editor
    Martin Holladay | | #3

    When the home was built, a few simple details would have changed everything - perhaps a capillary break between the footings and the walls, as well as a good layer of rigid foam under the slab and on the interior side of your walls. At this point, however, the simplest solution is a dehumidifier.

    Your story is a good example of how bad specifications at the time that a home is built can result in unfortunate ramifications (and high energy bills) years later.

  4. christine13 | | #4

    when the house was built, the basement walls and and floor were poured. walls are the styro foam formed - poured walls, water barriers installed, good drainage, drain tile, the whole nine yards..the floor is the floor, simply poured and made smooth. The basement has never had visible leaks, however we have rain gutters to divert water as well....the wetness seems to be condensation..for example where we have tiles - the floor "sweats". I assume thats because of the temp difference between the upstairs and downstairs. My energy bill excluding the dehumidifier is great!!! I spent 580.00 in propane for the entire year...not much more than that year before, the house stays very warm (winter and summer). I have had an energy audit done - twice once in winter and once in summer), I am doing all we can - they say the house "is tighter that a drum". After doing a ton of research here on the web - i think the prob is condensation - humidity issues. The question is...given the situation - one solution offered elsewhere was central air to equalize the temp of the entire it worth it, will it really work? Next question is I would like to finish my basement floors - aggregate rock as in the pebbles in apoxy like what you see around pools...will it continue to be wet?

  5. christine13 | | #5

    also, just realize my error in the description of my home..thats 1940 square feet, split entry

  6. BobHr | | #6

    I would look for the source and see if you can minimize it. On the basement floor tape some foil or saran wrap and see which side has the moisture.

    You said the home is tight as a drum so any moisture that starts in the house (showers, plants, cooking etc) need to be reduced with venting or find other ways to minimize the source.

    I know you said that you have down spouts and direct the water away but what kind of landscaping do you have against the house. If you have rocks or mulch pull it back and see if the ground is lower near the house. What is the topography around the house and on adjoining lots. Do they dump water on your lot?

    These steps may reduce the moisture load. AC would help with the problem provided it did not make the home to cool. If you dont need the temp reduction the look for the most efficient dehumidifier available.

  7. GBA Editor
    Martin Holladay | | #7

    If the taped-rectangle-of-plastic test shows that you have a condensation problem, then the problem is occurring because you open your windows during the summer. Summer air is humid, and that moisture is condensing on the cold concrete.

    There are two possible solutions to this problem (assuming that it is, indeed, a condensation problem):

    1. Insulate your slab. That would mean installing a continuous layer of rigid foam, followed by either a new concrete slab, or a plywood subfloor, or cement board.

    2. Close your windows and install either a dehumidifier or an air conditioner.

  8. wjrobinson | | #8

    Window AC up and dehumidifier down.

  9. BobHr | | #9

    He could have a couple of sources of moisture. It could be coming through the slab and since they do not have ac the humid air could also contribute.

    I should have mentioned to find a section bare concrete to do the test on. Both wall and floor if available.

  10. GBA Editor
    Martin Holladay | | #10

    I never said I knew the source of the moisture. I just said, "if your problem is condensation, this is what you need to do." We agree -- if the problem is condensation, that means that the slab is cool and the indoor air is humid. That is consistent with my advice.

  11. user-1022459 | | #11

    Central air will help reduce the amount of moisture in your indoor air, but we can not say if it will solve your problem because we/you do not know how much moisture you need to remove to be comfortable in your house. The problem with using an air conditioner to dehumidify is that the air conditioner primarily cools the air with dehumidification as a secondary function - it will not dehumidify without cooling your house. The air conditioner is controlled by a thermostat, so you will not get dehumidification if your house does not need cooling.

    A high efficiency dehumidifier will dehumidify your house until the indoor humidity is below your desired set point. Most high efficiency dehumidifiers will add heat to your house when they are running. A high efficiency dehumidifier will cost less to operate and will add less heat to your house than a low efficiency dehumidifier. Check Energy Star for efficient dehumidifiers.

    My company manufactures the Santa Fe (freestanding) and Ultra-Aire (whole house) dehumidifiers which are very efficient. We also manufacture a split dehumidifier that rejects the heat outside of your house - it is a very efficient dehumidifier and it provides a little cooling while dehumidifying.

    Should you choose the dehumidifier solution, there are a few things that can reduce the moisture inside your house and reduce the operation time of your dehumidifier as well as making your house more comfortable:

    1. Remove moisture you create inside your house at the source - use the kitchen hood and bath fans (vented to the outdoors) when cooking and showering to remove the moisture from your house.

    2. Keep your windows and doors closed when the outdoor dew point is higher than 50F - opening windows when the outdoor air dew point is higher than the temperature of your basement slab will cause condensation and cause your dehumidifier to operate for longer periods.

    3. Related to #2 - make sure you have an adequate amount of fresh air ventilation when your house is occupied. If your house is really tight, mechanical ventilation may be required. Many whole house dehumidifiers can provide mechanical ventilation as well as dehumidification.

    4. Make sure your rain gutters and ground grade outside the house direct water away from your house/basement to reduce the amount of water against your basement walls and slab.

    5. If your house is above an area with a high water table a drain/sump/pump system may help reduce the amount of water penetrating your finished basement.

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