Replies

1. 
   stamant | Oct 04, 2023 08:47pm | #1

   PAT is overkill. commercial style stickpins and speedclips -- either self-adhered or adhesive. consider painting the CMU first with a liquid applied air barrier. figure out if you need a fire-resistant cover for the exposed insulation.

2. 
   southern_water | Oct 04, 2023 10:02pm | #2

   Thanks. Could you share an example of what you recommend? I’m not quite picturing it. Code requires the vapor barrier against the CMU. I’ll affix the barrier to the CMU by drilling and using Christmas tree clips but I don’t see that being rigid enough to support polyiso without some sort of mechanical fastener.

1. 
   freyr_design | Oct 07, 2023 03:18pm | #3

   Faced 2” polyiso is a vapor barrier…

1. 
   southern_water | Oct 07, 2023 04:51pm | #4

   Thank you. Understand and appreciate that. However, code dictates min 6 mil poly vapor barrier extending across the floor and up to 3” below the top block. Additionally, there must be insulation as well but that has to end 3” above the finished floor. Unfortunately using polyiso as the vapor barrier is not feasible in this instance.

1. 
   freyr_design | Oct 07, 2023 08:48pm | #6

   Huh, just curious for my own knowledge what code are you referencing?

2. 
   stamant | Oct 10, 2023 10:29am | #7

   liquid applied vapor barrier then these mechanical fasteners:

   https://www.midwestfasteners.com/?gclid=Cj0KCQjw7JOpBhCfARIsAL3bobedRzh5ZWCkyMQlrmu_TXtjrxzgl5xcRDRSJcP-46IE1VUPPmO9zVcaAqNLEALw_wcB

3. 
   southern_water | Oct 07, 2023 04:53pm | #5

   What I’ve come to is a 3” pin to give me 1” of drive into the CMU.
   What I’m now considering is the order of the layers (as code is non specific).
   CMU-Poly-Foam board (now XPS and not Polyiso)
   OR
   CMU-Foam board-Poly