We are converting a small building on our property to a mother in law suite. The concrete has a vapor barrier underneath of it according to my brother who saw it when jack hammering to install the plumbing. We are installing laminate flooring over the concrete and according to my research we should do a vapor barrier underneath the laminate. My brother insists that the barrier under the concrete slab is sufficient. I cannot find anything supporting one way or the other and would appreciate some advice. We live in the Florida panhandle so it rains a lot and is very humid throughout the year. For me its a cheap safety measure for a 350sqft cottage but he is insistent it isn't needed.

1 Answer 1


There is a special underlayment that is used for "floating" flooring (either click lock type or edge glued type). It is a plastic backed foam which is sealed together with tape at its joints. This acts as a vapor barrier and also pads/softens the floor a bit.

The vapor barrier is a good idea- even if it is an "extra" vapor barrier.

  • Be sure to follow the directions for the particular brand and style of flooring being installed, though. Some call for particular types of underlayment, others call for different types, and some may call for none at all.
    – FreeMan
    Sep 27, 2022 at 12:15
  • Thank you both so much!
    – Kait
    Sep 27, 2022 at 19:08

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