Asked on Mar 14, 2012

I have a screened in porch and the floor is cement but it sweats when it rains what can I do to stop the floor from swea

Roger WilliamsJamesOdile Landry


16 answers
  • KMS Woodworks
    on Mar 14, 2012

    The sweating is "condensation" the cold slab reacting with the high humidity of the rainy day. This is just like the sides of a glass of iced tea. you can either remove the humidity....hard with a screened space. Or warm the slab / insulate it which is also hard. Being a screened porch this structure should be somewhat water resistant by its having a wet floor should not be much of an issue. Is there a reason you want this place to be 100% dry?

  • Carol G
    on Mar 14, 2012

    yes because I want to make a nice seating area with it and when it is wet it is there anything I can put on the cement to stop the sweat? like a sealer or something? I wanted to put tile down on it

    • Canadianlady
      on Dec 12, 2016

      We use garage flooring, which comes in rolls and is mega easy to install. It's not very expensive, either. It's also waterproof. In the Summer months, we have to use a dehumidifier to suck the moisture out of the air.
  • Carol G
    on Mar 14, 2012

    Thank you for the suggestions but this doesn't answer my question because it does not tell me if there is a solution.

    • Rock Griffis
      on May 15, 2019

      My front porch does the same thing, and I am thinking of building a wooden rise with the ability to drain or dry underneath it to avoid it being so slippery. What did. you ever do for your issue?

  • Peace Painting Co., Inc.
    on Mar 15, 2012

    I believe the issue is the natural temperature differential plus humidity, no matter what is on the floor. My stained garage floor occasionally does the same. Heard of Astroturf? CP

  • Carol G
    on Mar 15, 2012

    only that part does it the laundry room is an extension of the same floor but only half of the laundry room sweats..this floor was and addition..I think they did not put visquine. but the point is is there any thing I can use to stop a sealer? that is what I want to know...I know the cause...always did.

  • Carol G
    on Mar 15, 2012

    tried astroturf that is what was on it when I bought the house and it smelled mildew so removed it

  • Peace Painting Co., Inc.
    on Mar 15, 2012

    Carol, sorry I can't be of much help, that's a tough one on me. It may have to do with the visquine, I don't know. Chas.

  • KMS Woodworks
    on Mar 15, 2012

    The problem is a combo of the air working with the cool order for this to not occur one of those variables will need to be removed. The humid air could be removed by sealing in the room with glass or solid walls. The slab could be made warmer via a electric radiant heating element set under tile. The fact the the slab is not insulated below would have this "heating" be less than ideal in terms of efficiency. If you want a lower cost alternative to the slippery. A textured paint 'anti-skid" finish can be applied. The concrete will still cause some condensation to form but at least the "traction"will still be there. A built up "insulated floor" is another option, but this would require some engineering to keep horizontal rain from compromising the new surface. A wooden "deck" could be installed over the concrete on thin PT sleepers. This would have the condensation still form on the concrete but the wooden surface above would still be dry and usable. The decking would be "weather proof". This decking could be real wood or one of the many synthetics.

  • Charlotte Smith
    on Feb 19, 2014

    I recently added a screened in patio and it sweats most of the time. Is this normaI? I do live in the Houston area where humidity is always high. What can I do to prevent this sweating?

  • Jody Forslund Wicker
    on May 28, 2017

    I installed some industrial fans from Home Depot couple weeks ago this is the most brilliant thing, I have not had any floor sweating since !! The fans are designed with a wall mount with four-speed's, on the rainy days I keep them in high. Hampton Bay Industrial 60 in. White Energy Star Ceiling Fan
    $56.98 / each

  • Kym Langford Ball
    on Jan 23, 2018

    I have the same problem. I have ceramic tile over a cement slab in a screened-in sunroom. I have an exorbitant amount moisture / water sitting on top of my tile. I would take my Hoover FloorMate out pretty much once a day and soak the water up so that my dogs did not track it inside.

    I finally got tired of it. So I chipped all the porcelain tile up which was nice is it had a skid resistant anti-slip on it. I installed in Italian type tile it was kind of like a slate. It's a little more difficult to clean however since I have put this down in the past two years I have not had the sweating tile over the cement slab in Florida like I did with the ceramic tile

    This post is old so I'm not sure if it will work for you now but I did find more of a slate or an Italian type of a tile worked much better than a ceramic or porcelain and sweating
  • Gilmer Gal
    on Feb 17, 2018

    The sweating on my East Texas ceramic floored, screened porch makes me want to cry every time it happens! Something the sellers didn't mention :(. Anyway, I was thinking of putting some wood-type flooring down, maybe strip some underlayment into 8" wide strips, (first seal with Red Guard over the tile that is there). The wood on the porch never sweats, so I'm going to lay down a few strips of wood and wait for the next humid day to see if it helps. Seems to happen when the weather changes from cold nights to drizzly days. Nightmare. I keep the litter box out there and my cat has wet feet and tracks it inside. On my wood floors!
    • Raynee
      on Dec 29, 2019

      My first thought is her wood is absorbing the moisture, so she's not necessarily seeing it, again that's just a thought I'm certainly no Carpenter

  • Odile Landry
    on Mar 4, 2018

    I have a patio with all windows and my patio sweats just like my carport does , what can I do it’s driving me crazy ?
  • James
    on Feb 25, 2020

    I was just wondering if anyone has tried a fan underneath porch, which could not only blow some moisture from underneath house and more importantly cause the porch floor to be closer to same temperature as air and reduce condensation.

  • Roger Williams
    7 days ago

    I have the same problem with a covered concrete porch each time it rains. My porch is soaking wet, almost like it rained on the porch with no covering at all. It does this whether there is any wind or not, so it has to be something in the concrete causing it. I have not found a solution either.

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