Tips on How to Prevent Wood Floors from Buckling

Buckled or cupped wood floors are often caused by ground moisture in the crawlspace under your home.

To reduce humidity and moisture levels under your home, cover all the ground in the crawlspace with thick (6 mil) plastic sheeting. Watch this video to find out more.

Further Information

Gary Asks: What’s causing my wood floors to buckle? The crawl space seems to be dry.

Danny Lipford: I think everybody loves the look of a nice wood floor. But it’s not so nice-looking when it starts buckling, and that’s a problem that generally starts outside.

If your house is built up on piers, and many are, you might be surprised at how many problems can be caused by ground moisture. Now, it may look perfectly dry under your house. But the moisture’s there, and it’ll migrate up into your house, causing all kinds of headaches, including buckled floors. Here’s what you need to do.

Make sure you have adequate ventilation at all times throughout the year, and a great tip is to lay a piece of thick plastic. This is six mil plastic, a lot thicker than you might be used to, right on the ground, put a little sand around it. And if you catch this early enough, hopefully your wood floors will dry out and go back down.


  1. I am trying to properly insulate the crawl space under my home that is 4′ above the ground. I live on the water and in the winter my floors are cold. I have a new heat system in place, but would like my house to be more efficient. I have batting insulation that has been under the house for 30 years. I was going to add a 3/4″ sheet of insulation board under the joices, but have doubts about that. From your video, I feel I should add the plastic to the ground and then replace any batting that has fallen down. Please advise. Thank you for any help!

    • Hi, Leslie,

      Danny says, “Do not put any foam board nailed to the bottom of your joists. This could create a serious moisture trap issue. However, putting plastic down on the ground is a great idea. Reinstall any of the sagging insulation and then supplement that with mineral wool insulation available from Rockwool. It is easy to install, moisture resistant and is perfect for crawl spaces.

      Good luck!”

  2. I have old house 1950 and my wood floors keep buckling I put moisture barrier under the house and put another floor over my wood floors and there buckling again I need help on what to do

  3. after 38 yrs. my floors are starting to raise at some seams. 2 companies want me to encapsulate for$ 12,000 . I live in Va. it can be humid , can l replace the plastic sheet an d insulation only ?

    • Hi, A.,
      Danny says, “Yes, that’s what I would recommend. Encapsulation probably is not necessary. Thanks for your question!”


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