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

Crawl space spray foam in CZ 3c

Mike C | Posted in Energy Efficiency and Durability on

I’m currently undergoing a whole house renovation in the Bay Area, CA (CZ 3c) and have an existing vented crawl space to work with. I’d like to spray foam the subfloor (vs encapsulating the crawl space) but wanted some clarification around a couple options.

1) I had thought that closed cell was my only option here, but saw Dana’s reply (#2) in this Q&A: https://www.greenbuildingadvisor.com/question/spray-foam-from-crawlspace-onto-bottom-of-plank-subfloor-in-pacific-nw

Is using open cell a viable (and even preferred) option in my climate zone?

2) If going with closed cell, is encapsulating the entire floor joist with foam necessary in my CZ to prevent moisture-related issues in the subfloor, or can I get by with only spraying cc foam between the joists?

Thanks
-mike

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
    Zephyr7 | | #1

    Why do you want to insulate the subfloor instead of conditioning the crawlspace? It's usually easier to encapsulate and insulate the crawlspace, and that generally performs better too.

    Bill

  2. Mike C | | #2

    Encapsulation is not commonly performed here so I’m not confident it would be done well. On the other hand, spray foaming the subfloor is something that should be relatively straightforward.

Log in or create an account to post an answer.

Community

Recent Questions and Replies

  • |
  • |
  • |
  • |