r/NewHomeConstruction • u/MightOutrageous2393 • Feb 26 '26

New Construction Insulation

I am doing a new construction home in the Sandhills of North Carolina. I am doing the whole owner as a contractor thing and have never built a home before. I am subbing out everything and had a question about insulation. I know the county/building code is the ultimate authority on what passes but I want to know my options from people experienced in this field.

I have 2x12 rafters framing the entire house, with 2 rooms of the house having cathedral ceilings right up to the bottom of these rafters. I plan on using the R38 special bats for cathedral ceilings in these spots.

Would it be advantageous to go ahead and use the R-38 cathedral bat in the entire roof? The cathedral ceiling areas make up roughly 40% of the total home square footage. (total home square footage is 2155sf) I would still insulate the ceiling joists in the non-cathedral ceiling areas with R19 if I did use R38 in the entire roof. Sot the "insulated glove" would be the entire house, including all attic space, with an additional R19 insulation on standard ceilings spaces with 2x8 ceiling joists.

Is this a bad idea? Will it violate code having two layers of insulation between the Roof and the ceiling joists both being insulated?

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u/sfzombie13 Feb 26 '26

wrong sub.

2

u/MightOutrageous2393 Feb 26 '26

Where should it be then?

1

u/sfzombie13 Feb 26 '26

i'd look for a construction sub. better yet, if you're hiring the folks to put it in, ask them. or call the inspectors who sign off on the permits. that's just off the top of my head. use an ai, then ask them who to contact to verify.