How To – Insulating Foundation Walls

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    There are 2 basic ways that you can insulate your foundation wall and doing so is important if you want to have a comfortable living area in your basement.

    The first method is to install foam insulation board on the exterior of the foundation after it has cured but before it has been back filled with dirt. This step can only be done at the time of construction.

    Note: When installing foam board insulation on the exterior of a foundation it is important to remember that over time the material will break down. This may not happen for 10 to 20 years but the pressure of the soil along with other physical influence will still cause the product to degrade. This could cause a pathway for termites or possibly radon gas. Long term studies of the use of foam insulation has not been available because the product has only been in use for a limited number of years.

    This is not to say that the product is not worth installing it is just a factor that you must include in your decision making. Similar to the realization that some day your vinyl siding will need to be replaced due to UV light breaking it down.

    Installing Insulation on the Interior of the foundation.
    On the inside of your foundation you can make use of a variety of different insulation types. Foam insulation for interior application is made specifically to allow its direct application to your walls by using 1×4 furring strips and concrete nails which hold the product in place and also offer attachment points for interior wall board.

    You can also build a standard stud wall on the interior wall by first installing 10 mill or better poly plastic sheeting around the wall sealing all openings with duct tape. This will act as your vapor barrier and is better suited to water transfer that may happen in a basement then standard foil or paper vapor barriers found on standard fiberglass bats and rolls.

    Make sure that you seal all cracks in the wall with a good grade siliconized caulk and use a Spray Foam in a can to fill larger voids. Once your wall is up you won’t be able to go back and catch problems. Some people will take the extra step and paint their foundation wall with a water blocker. This is a good idea and the product can often be found much cheaper in a 5 gallon contractor grade can but it does not eliminate the need for poly plastic.

    Once your vapor barrier is in place build your stud wall and then install your insulation in a normal method. If it costs less there is no need to buy insulation with a vapor barrier but often since it is used more often product with the barrier will cost less. You should install the paper barrier towards the foundation wall if you purchase this type.

    Some people will go the added step and use a spray in foam insulation. This product is good in many situation especially when you are dealing with a stone built-up foundation but for recent construction and poured concrete formed foundations you do not need the added cost of this product or the horrors it can bring when you need to tare it out to make repairs or remodel.

    Once the insulation is up you can continue building your stud wall and applying wall board as you normally would above ground.

    Special Note On Mold
    Today many manufacturers are offering a fiberglass faced gypsum board. This is ideal for basements because it will reduce the growth of mold however it is not the be all end all to water and mold problems in your basement. You most likely will need to use a dehumidifier if you are using the basement for living space. You should also keep a close eye on your plumbing as any leaks in an already humid environment will cause mold to grow faster.

    The YouRepair Store carries a full line of Insulation products

    that can be delivered to your home just like your local retail business will.

    We also provide free delivery on many orders over $25 while also offering the best price.

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