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Community and Q&A

Advice for basement wall and flooring on an uninsulated basement slab

ama666 | Posted in Green Building Techniques on

I am insulated a basement with a very low head room and cannot add any insulation to the floor. I am insulating the exterior walls and I have a trench drain and sump on the interior perimeter of the basement. This had been installed before moving in to the house. No water has shown up in the basement in the last 4 years.

The walls are fieldstone and I intend to use spray foam and provide a dimple mat along the fieldstone wall to funnel any water into the trench at the perimeter. Not sure if this dimple mat should go up the side completely or not.

Because of low head room, I need to install flooring without a layer of insulation. I am thinking about a floating cork system and trying to decide if I should use a vapor barrier below or not. I am also open to other flooring suggestions.

Any advice would be appreciated.

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  1. Expert Member
    Dana Dorsett | | #1

    Using moisture susceptible materials for the floor is not a good idea. I'm not sure how well cork flooring will fare over time. Ceramic tile, or stained concrete can work, as can a a purpose made heavy epoxy vapor barrier floor paint, after you've hard-troweled a good bonding floor leveler or something to make the surface super-nice & smooth.

  2. ama666 | | #2

    Thank you for your response. I am looking for a final surface that is warm and soft for little feet. This is why I am looking at cork. I have heard so many mixed responses to having a vapor barrier vs. not . Vapor barriers are potential problems but if we want to not use tile or concrete it seems like it might be the best solution. I do know what you are saying though.

  3. gusfhb | | #3

    There are vapor barrier adhesives that are pretty effective
    How low a ceiling is a low ceiling?

    The first inch of insulation is the most important

    OR half inch

    or quarter inch..............

  4. GBA Editor
    Martin Holladay | | #4

    Moisture-susceptible flooring materials only make sense if you can install a layer of rigid foam. (Otherwise, you are likely to get summertime condensation that keeps your flooring damp.)

    If you want, you can throw down some inexpensive (small) area rugs. When the rugs get wet in July and August, you can take them outdoors an hang them on a clothesline. Keep rotating your damp carpets with your dry carpets...

  5. ama666 | | #5

    Thanks for all the feedback.

    I'm curious how thin a rigid foam layer is possible to make the difference?

    Ceiling is approx. 7'-1" unfinished. May also need to level the exist concrete floor a bit too. Intention is also to keep basement conditioned so that the humidity level is controlled.

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