Replies

1. GBA Editor
   Martin Holladay | May 02, 2018 04:13pm | #1

   Eddie,
   Are you talking about sheet vinyl or linoleum?

   I was unable to find a reputable source that lists the vapor permeance of linoleum, but I would guess that it isn't very permeable. It's probably a vapor barrier.

   Sheet vinyl flooring has a very low permeance, and is therefore a vapor barrier.

   What is your climate? Why are you concerned?

2. GBA Editor
   Martin Holladay | May 02, 2018 04:17pm | #2

   Eddie,
   See the screen shot below. I have no independent source of information to verify this author's claim.

   .

   
3. 
   user-7064774 | May 02, 2018 05:02pm | #3

   Thanks Martin,

   I know sheet vinyl is a vapor barrier but was not sure about linoleum. I am in a hot and humid climate. Thanks for the article. It verifies that linoleum would probably act as a vapor barrier in this climate.

4. GBA Editor
   Martin Holladay | May 03, 2018 05:36am | #4

   Eddie,
   If there is a basement or crawl space below the floor assembly, there shouldn't be any worries about the vapor permeance of the flooring. (Assuming, of course, the the basement or crawl space is unvented and conditioned.)

   If this is a house on piers, and you are worried about inward vapor drive during the summer, the usual solution is to install a layer of foil-faced polyiso on the underside of the floor joists. (The polyiso stops inward vapor drive.)

   This approach should allow the use of any type of flooring, even vapor-impermeable flooring, without worries. You'll need to protect the exterior side of the polyiso with plywood or OSB, of course.