GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter X Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Above Slab Vapor Barrier Needed?

drrenken | Posted in Energy Efficiency and Durability on

I am just outside Atlanta and I am planning on insulating on top of my new construction slab with 1″ XPS (cheap marketplace find), two layers of 3/4 subfloor and then 3/4 hardwoods. Going this route for a couple of reasons, but my question is do I need to do a vapor barrier underneath the XPS? I do have a 15 mil vapor barrier underneath the slab. Thanks!

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.

Related Questions

Replies

  1. Malcolm_Taylor | | #1

    drrenken,

    A concrete slab needs a vapour-barrier. I you have an effective one below the slab, you don't need another one above.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |

  • |

  • |

  • |
View More Ask a Question

Featured Blogs

Musings of an Energy Nerd View More

Contemplating residential energy use

Product Guide View More

Double Check

Do you really want to delete the list, ?

Note

This won't delete the articles you've saved, just the list.

This feature has been temporarily disabled during the beta site preview.

You must be a magazine subscriber to access this feature.

Subscribe today and save up to 44%

Subscribe

Or learn more

Already a subscriber?