How can I prevent moisture on my cabins floors?


We have a cabin that is built on a concrete slab. In the summer it sweats. What can I do to prevent this?

  7 answers
  • Oliva Oliva on May 30, 2020

    Hi, Dayne,

    Ceiling fans , bathroom exhaust, stove hood exhaust and window fans may be your only options, unless your cabin has the luxury of air conditioning. A dehumidifier would only help if you could pump the water outside, far from the cabin foundation.

    If you have the strength and energy, you might look into digging a french drain around the perimeter, but since concrete wicks moisture, I'm not sure this would necessarily be sufficient. If the cabin is shaded, you could also evaluate opening the tree canopy, if this exists. Do you have adequate drainage, or is the cabin situation at the bottom of a slope? Anything to divert water away from the foundation may help you.

  • Dayna Dayna on May 30, 2020

    We do have ceiling fans that we run when we are here, I was hoping there might be some kind of barrier I could use in between floor coverings? Thanks

  • Seth Seth on May 30, 2020

    Hi Dayna,

    It's not just a moisture barrier you need, but a thermal break. Condensation will occur anywhere between materials of different temperatures (cooler concrete and warmer flooring) and high enough humidity. Now, basement floors and walls and slabs are insulated with rigid foam below the slab to prevent what you are experiencing. At least two inches of rigid foam is needed. That, however, is probably not practical for your situation. A dehumidifier may be your best bet, but will not be effective if you keep doors and windows open. There are moisture barrier subfloor and underlayment systems. You will need to weigh the cost and effectiveness to determine if you want to undertake that extensive a project.

  • Agnes Chrzanowska Agnes Chrzanowska on May 30, 2020

    you need to install good ventilation and add subfloor barrier

  • Mogie Mogie on May 30, 2020

    Do you have a crawl space under the cabin or does it sit directly on the slab?

    If you have a crawl space this might help.

  • Mogie Mogie on May 31, 2020

    Is the grade (does the land) slope inwards towards your property or is run off pooling around the cabin? The presence of natural ground water can also cause a moisture problem.

    Ambient conditions can also increase the concrete slab’s water content. As well as a torn vapor barrier.

    Does the cabin seat unheated in the wet and cold months?

    So, it's a good idea to peek into the framing near the slab level to see if you have any rot happening.

  • Dayna Dayna on Jun 01, 2020

    Yes it is not heated during the winter, closed up from October till end of April. It’s in Northern WI