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

Puncturing Smart Membranes

potton | Posted in Energy Efficiency and Durability on

Does nailing battens on a ceiling or wall to create a service cavity creates significant leaks to worry about?  Or afterward stapling wires, screwing jonction boxes, etc. through the membranes.

[This is a single level construction in zone 6 where:
– ceiling is a vented cathedral roof with R60 cellulose, over 1/2” Enermax (wood fiberboard with aluminium foil vapor barrier), double 1×3 strapping and v-groove pine planks.
– walls are cedar siding, 1×3 strapping, Typar WRB, 1-1/2” wood fiberboard, R-20 hemp batt insulation, smart vapor retarder ProClima Intello, double 1×3 strapping and v-groove  planks.]

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.

Replies

  1. Expert Member
    MALCOLM TAYLOR | | #1

    Potton,

    As Joe Lstiburek points out, strapping actually provides an air-seal for the fasteners.

    1. potton | | #2

      What's about a nail that split the strapping? Should we tape it?

      1. Expert Member
        MALCOLM TAYLOR | | #3

        Unless it happened a lot, I wouldn't worry much about it.

        1. potton | | #4

          Great.
          Would it be the same for electrical box screwed directly through the membrane, and wires stapled/clamped directly through the membrane ?

          Thanks!

          1. Expert Member
            BILL WICHERS | | #6

            The hole for the wire needs to be sealed. The fasteners (screws or nails), when driven through, will essentially “self seal”. That same tight fit when a nail is pounded into wood also forms a seal around the nail. It’s mostly holes you cut or drill that you need to worry about being air leaks.

            Bill

    2. potton | | #7

      Ok for air-seal, but is it true also for vapor-seal ...?

      1. Expert Member
        BILL WICHERS | | #8

        Yes.

        It’s actually easier to maintain a vapor barrier since a vapor barrier is much less critical regarding detailing like holes and seams compared to what is required to maintain a good air barrier.

        If you have a good air seal, you’re pretty much guaranteed to have a good vapor seal too.

        Bill

  2. Robert Opaluch | | #5

    When you do a blower door test prior to installing drywall, you can do a smoke test to find leaks (and try to fix them). You can both pressurize and depressurize your building with a blower door test, and try a smoke test adjacent to any places you suspect may have created an air leak. A smoke test might be attempted from either side of your air barrier. If you find a leak, you can attempt to plug it. Or be satisfied with your air barrier whenever you don't find anything.

    See this related excellent article:
    https://www.greenbuildingadvisor.com/article/using-smoke-to-find-air-leaks

  3. GBA Editor
    Kiley Jacques | | #9

    Christine Williamson created an entire website related to your concern: Overdriven Fastener.

    1. potton | | #10

      Thanks, very interesting.
      She wrote about water leaks, but I was worrying about air leaks…

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |