Attic insulation

[Yadkin]

More than one way to skin a cat.

"Attics can be designed and constructed to be either vented or unvented in any climate zone. The choice of venting or not venting is a design and construction choice—not a requirement determined by the building code. The model codes allow both vented and unvented attic assemblies."

https://buildingscience.com/document...-unconditioned

[DJ_Critterus]

Who are you trying to impress or argue with, now?

[LATB]

I’ve done it both ways many times.

[Big bob]

Originally Posted by DJ_Critterus

Who are you trying to impress or argue with, now?

He just figured out he ****ed up again and trying to justify it.

[Vandelay Industries]

OK

[Onebadcad]

I am betting more FU posts than posts on subjects,,, learned this from his last one.

[Frankie the Fink]

Read the article a bit, and I wouldn't trust 90% of general contractors to properly build an unvented attic; you need a lot of special considerations to avoid condensation, water and mold issues and I'd bet few subdivision builders would even consider it, but you could prob force some reluctant builder to do it on a custom home, for better or worse.

[Yadkin]

Originally Posted by DJ_Critterus

Who are you trying to impress or argue with, now?

Thanks for your false dichotomy.

[LATB]

Originally Posted by Frankie the Fink

Read the article a bit, and I wouldn't trust 90% of general contractors to properly build an unvented attic; you need a lot of special considerations to avoid condensation, water and mold issues and I'd bet few subdivision builders would even consider it, but you could prob force some reluctant builder to do it on a custom home, for better or worse.

Subdivision/tract home builders are not doing it because of cost.

Custom/semi custom builders do it regularly without problems.
It's not really that hard to get right and not a big deal.

Personally, I have done it on others' homes and my own home in the past...and I am not a big fan. I will not be using foam on my new build, I will be doing a traditional vented attic with fiberglass ceiling insulation.

[IrishSpuds]

Didn’t read. But our attic is insulated with Christmas decorations and a pile of old flammable crap. Only two furnaces up there…

[DJ_Critterus]

What's the benefit of unvented vs vented?

[Onebadcad]

Originally Posted by DJ_Critterus

What's the benefit of unvented vs vented?

[LATB]

Originally Posted by DJ_Critterus

What's the benefit of unvented vs vented?

The unvented has foam insulation on the underside of the roof sheathing. This in effect makes the attic a conditioned space because HVAC drifts up there through the drywall. Some even add an HVAC vent to supply HVAC in the attic.

The theory is the attic is only a few degrees different than the house in this case and it (in theory) will reduce your HVAC costs/make the system more efficient. As opposed to the traditional vented attic where the attic can be 50 degrees warmer than the living space thus reducing the efficiency of the HVAC.

[Unsuspicious]

Originally Posted by DJ_Critterus

What's the benefit of unvented vs vented?

Unvented, you can condition it like the rest of the house and then grow your pot up there

[lrobe22]

Originally Posted by LATB

I’ve done it both ways many times.

that's what she said

[DJ_Critterus]

Originally Posted by Unsuspicious

Unvented, you can condition it like the rest of the house and then grow your pot up there

Damn, that's why my plants won't grow

[Unsuspicious]

Originally Posted by DJ_Critterus

Damn, that's why my plants won't grow

To grow plants that will get you high, they must be grown in the highest part of your house.

[Craig]

I had spray foam installed in our attic, probably the best money I’ve spent on my home.

[GTOguy]

Originally Posted by Big bob

He just figured out he ****ed up again and trying to justify it.

You're just showing off your cluelessness with this statement, Bob. Yadkin never justifies anything. Because Yadkin.

[Yadkin]

I've owned three homes. The first was a simple ranch built with a truss roof in the 79s. Had 3" of treated paper insulation on the attic "floor", vented. I added 7" unfaced fiberglass perpendicular to the trusses. Made a huge difference.

My second was a large colonial built in the 90s. Had 12" of blown in fiberglass, again on the floor, vented. HVAC in the attic. I added another foot of insulation and a reflective barrier.

My third house I built. Cathedral ceiling. So R38 fiberglass batt in the rafters, vented. Had to close off the ridge vent because of high winds. My addition has R60 in the rafters, unvented.