re: Foam insulation in new construction

Have seen it used very effectively in basements along the foundation wall, but Louisiana is not exactly known for having basements .

That said research the differences between open and closed cell foam and figure out what is best for you.

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Louisiana is not exactly known for having basements

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That's gotta be South Louisiana right, but I thought North Louisiana would have basements cause I thought that was in tornado alley. I'm ignorant of your part of the world though.

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Yeah I’ve heard that too but there is another camp that says houses don’t need to breathe. Even with regular fiberglass insulation, houses these days are tight compared to 50 years ago.
I built my house in 2015 and went with spray in from concrete to roof tip. No issues and my heating/ cooling system has no problems. Even went half ton less on the outdoor unit. More and more people are going with the spray in.
I like it because when i go in the attic it is cool and I can see all my wiresu and plumbing without having to dig around in insulation.

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Circulation is always important. And a tight house saves $. Going with closed cell spray and installing a fresh air intake allows you to both without any cause for concern. If you are on a crawl closing and encapsulated crawl with intake for crawl is only way to go as well. Spend the money on the bones. Aluminum clad casement windows & ZIP system and you are living worry free for a long time

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I gotta dumb question for ya, how is a log cabin insulated?

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Most are not insulated. Logs have a natural R value of about R13. All depends on the size of logs used and chinking.

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Cost not really the issue. Just want to hear testimonials... I like it but Ms. Nagin has concerns.

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Spoken like an OT BOSS

About to start a new project myself. Will go with this technology, maybe even geothermal too. Vinyl windows would be a weak point, IMHO.

Make sure your plumbing and electrical are done how you want it.

Once you spray that foam, its a huge pain in the arse to fix or change that stuff.

I am an estimator at a large insulation company. If you want my opinion on how to go about insulating, post an email address and I'll contact you.

In short, if I'm building in the SE, I would have my attic/crawlspace conditioned - unvented, sealed, and tied to my HVAC. "Venting" in the SE is tricky, as you're bringing in humid air almost always. So I would use a closed cell SPF on the crawlspace up to the decking. An R10 (1.5") is sufficient for stem walls, go R19 (3" at rimjoist). For that attic, spray directly to the roof deck and gable ends. For N. Louisiana, I would go with an R15 (2.5" closed cell to the deck), which is required for air impermeability, then either wire an R19 unfaced batt to the deck, or finish it off with 5" of open cell on top of the closed cell. For your walls, use a 1" flash closed cell in the cavities, and if it's 2x4 framing, an R13 batt on top, if 2x6, an R19.

If you insulate your foundation as previously stated, you do not need insulation under your floor. Just make sure you have a substantial vapor retarder on the ground, rising at least 1' up your stem wall and piers. I definitely recommend spray foam, and going to conditioned attic/crawlspace, but only if you have your HVAC company design your system to remove humidity from said areas.

If you go that route, the air quality and comfort of your home will be phenomenal.

Also, another benefit of insulating on the deck of your roof, you keep the ceiling area clear of insulation.

Also, the closed cell SPF will offer you much better structural integrity, keep pests at bay, and make your house much quieter.

ETA: And if you insulate how I stated, all of your electrical and plumbing is in direct access to you at all times in your crawlspace and attic, and if you need to access in your walls, you only have to pull batt insulation out. The main goal is stopping air infiltration, how I described does just that in the most cost effective manner.

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Open cell beneath roofed areas allows for leakage sites to be found.

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I would rather replace roof decking than the interior of my home. If your underlayment is installed correctly, it's a non-issue, and a leak will be evident at your eaves.