GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter 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

Radon Mitigation Question (Tu Tuff Liner)

John_Brown | Posted in GBA Pro Help on

I am working on a design of a small (12′ x 16′ — 192 sq ft) workshop with a crawlspace that will most likely need some kind of radon mitigation plan. I definitely understand the details and “strategy” of initially putting in the perforated pipe and riser, then capping it so that a “passive” system is in place. If the picocurie readings are high, then one is in a good situation to finish the system or make it an “active” system with an inline fan. My question is this. Why couldn’t one simply use a Tu Tuff liner under the inner slab AND extend it out underneath the footing so that one could block it all together? I am most likely going to use a heavier vapor liner because my space is so small and I would like to avoid having a 3″ pipe run up through the space.

I have seen a few footing details that show a vapor barrier under the footing but those are mostly mono-slab pours. I was wondering if a crawlspace might allow for such an assembly.

Any thoughts on this are appreciated.

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.


  1. GBA Editor
    Martin Holladay | | #1

    You can install a layer of polyethylene under the footings if you want. When it's time to install the Tu-Tuf over your crawl space dirt, you can tape the Tu-Tuf to the polyethylene that you installed under the footings (assuming that you left adequate flaps to tape to).

    It's also possible to install a layer of polyethylene between the footings and the stem walls -- and if you do, you can also leave enough protruding polyethylene to tape your Tu-Tuf to. For more on this technique -- including a discussion of its advantages and disadvantages -- see Capillary Breaks Above Footings.

    All of this said, I'm not sure that these steps will limit radon entry compared to more conventional methods. They can't hurt, however.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |