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IRC 2024 coming soon

jollygreenshortguy | Posted in General Questions on

From the 2018 to 2021 IRC we saw a large increase in required insulation values. It’s only in the last few months that I’ve seen people referring more and more to the new, increased values.
However the 2024 IRC is going to bring the insulation values back down to the 2018 levels.
I’m wondering how many jurisdictions will simply skip the 2021 change.
And of those who have already adopted the 2021 values, I wonder if they will be going back to lower values.
What are your thoughts on that?
What have you been experiencing in your areas?

Here is a link to the draft 2024 code. The insulation stuff is on page 108 of the PDF.

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  1. Expert Member
    ARMANDO COBO | | #1

    IMHO, the largest majority of homes built in the US barely meet minimum code, regardless which version is approved in their municipality. That will not change any time soon, I suspect.

    Most of us folks that are in the business of designing and building high-performing homes will continue to offer our clients above code options. Many of us have enough knowledge, education and experience to explain to our clients the benefits of building a much better house.

    1. jollygreenshortguy | | #2

      Thanks, Armando.
      This is off topic but I believe I've heard you work in the southwest of the USA. I've been curious to find resources on good ways to design adobe walls with additional insulation. Can you recommend any books or online resources for that?

    2. Expert Member
      ARMANDO COBO | | #3

      I designed a handful of houses that had interior adobe walls and exterior modern construction, like conventional frame walls and ICFs. The main reason is that adobe construction, as in the old days, are very difficult and expensive to build right and the building science of today is much more advanced with many more benefits than back in the day without electricity, insulation, moisture management, etc.

      In the SW, there are only a handful of builders that still build true, full adobe homes. Awhile back, the Taos Pueblo, offered a week-long training on how to build with adobe, but it is my experience when I visited several adobe-built homes in NM that all of them had issues.

      One of the key issues that makes it more common in the SW is the dry climate and that most old adobe homes were designed with small rooms and short structural spans. Many of today’s adobe homes are very large open concepts with a lack of understanding design, engineering and building science.

      You can reference ASTM E2392/E2392M-23 for more information.

      You can find many titles on Amazon, Google or here -

      I just thought of Santa Fe Community College, I think they offer a program in adobe construction.

      1. jollygreenshortguy | | #4

        Thank you, Armando. This was very helpful.

  2. Ryan_SLC | | #5

    I can't find a single example of a company or experts detailing crawl space rigid foam fire ignition or thermal barrier. Not from forums and not from crawl space big names.

    In fact, most comments are to "consult with your local inspector." Why? It's code and it is product required.

    However, that's a total bad answer. Owens Corning clearly states multiple places XPS MUST be covered with a thermal barrier. Thermax isn't air quality certified and is actually questionable how right they present this as a true 15 minute barrier.

    While interest in R Values, as a home owner trying to do a project, it would be nice to see experts catch up with the minimum required thermal barrier requirement details in a crawl space using rigid foam. Everywhere seems to say how they do it right, but come time to talk an application meant to not kill the occupants, arguably orders of magnitude more important than R38 vs R49...almost a non exaggeration to say nothing out there exists for details on this code required and product required component.

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