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Which R Rating to use?

Discussion in 'Residential Energy Codes' started by Danny Taylor, Oct 20, 2018.

  1. Danny Taylor

    Danny Taylor Registered User

    Oct 20, 2018
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    My house was damaged by Florence. Currently 80% is down to studs. I'm thinking about doing insulation myself to have some extra $$ to do other things. I'm in NC, what is current minimum R rating for walls and attic?

    The attic had blown in insulation. It got wet due to roof damage and the ceilings collapsed. I was looking at going back with batten. Is one better than the other?
  2. jar546

    jar546 *****istrator

    Oct 16, 2009
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    There is nowhere near enough information here. When you apply for a permit, you will have all the access to that information you need. NC is not specific enough for code requirements as elevation has a lot to do with the energy code.
  3. Keystone

    Keystone Sawhorse

    Feb 23, 2010
    Likes Received:
    Do yourself a favor and get a few price quotes even with your intentions. Most folks in my area find the cost of having a company complete the work as opposed to the owner is extremely minimal. Complete a cost comparison of buying your material including disposable hooded suit, mask, gloves, cutting edge, knife and blades vs. having an insulation company complete the install.
  4. georgia plans exam

    georgia plans exam Silver Member

    Oct 19, 2009
    Likes Received:
    What city / county are you in?
  5. HForester

    HForester Member

    Sep 21, 2015
    Likes Received:
    The ICC Website indicates that NC has adopted the 2018 NC Energy Code. Free viewing available at:


    Because all of the insulation in the house has been removed, what you put back must meet the current code that you will be obtaining the permit for doing the work.

    Section R301.1 will help you identify the climate zone that the building is in. Note if your location is a Warm-Humid zone as that might be important information for complying with other code sections.

    Table R402.1.2 specifies the minimum R-values for ceilings and walls and floors as applicable. If you can't comply with these prescriptive requirements because the existing building's limitations, ask your code official how to proceed.

    There are many installation details and checks throughout the energy code so read all of the Residential (R) sections and ask questions of the code official.
  6. Paul Sweet

    Paul Sweet Sawhorse

    Oct 17, 2009
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    Batten and blown-in fiberglass have almost the same R-value. You should go by the Existing Building Code for repairs. Basically repairs shall not make the building less conforming than it was before being repaired.

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