California title 24 high performance attics

Is anyone familiar with California title 24- high performance attics. I’ve looked through the blogs and not found anything.
On inspecting an 1 year warranty inspection I noticed the attic being hotter and more moist, only to discover the venting throughout this home to be blocked. Problem #1.
Concern #2 is the insulating of roof decking material. Ive been trained to call this out without proper Baffling to ventilate. No baffling here and no Radiant barrier plywood( foil covered ). I believe this to be a moisture trap and the builder said this was new code from California title 24 high performance attics.
I even reached out to a local Insulation contractor for clarification - they replied it was installed improperly.
Looking for answers …?

Sounds like conditioned attic with hot roof, was there insulation on the floor (looks that was in the 2nd pic) of the attic, which would typically be incorrect for conditioned attic? vents from HVAC?

Was the attic conditioned space? Was there ventilation at the soffit/eave?

Yes to horizontal insulation and soffit venting. ALL venting was covered by the contractor which is being addressed now

IRC 806.3 Vent and Insulation Clearance

Where eave or cornice vents are installed, insulation shall not block the free flow of air. Not less than a 1-inch (25 mm) space shall be provided between the insulation and the roof sheathing and at the location of the vent.

When you create a hot roof which was done incorrectly by the use of fiberglass insulation on the underside of the roof’s deck… you’re not supposed to have any air vents to the exterior. You should defer this to a very qualified contractor who understands how conditioned attics are to be created.

Yes, my next call is to Western Insulation Contractors Assn. Thank You All!

Amazing that this passed inspection… they either missed it or also have no clue what they are looking at.

Looks like conditioned attic. I think you nailed it by asking if HVAC vents present, hoping that they don’t create venting to exterior and HVAC vents present, that’d be a wee bit of a problem… kinda like throwing money out the window while driving.

The fiberglass on the underside is a huge problem by itself, forget other issues. Hot roof must be 100% air sealed, fibgerglass will act like a filter and create all sort of moisture related issues.

Good points… hadn’t considered migration of moisture thru the glass batts. Not really seeing them where I work, is closed cell foam used, or what’s ideal? Most all new/newer construction in my areas is that of a radiant barrier / Techshield sheathing, batts at bottom chords covered with loose fill to R-38 or better.

Conditioned attics are as new as conditioned crawl spaces, rarely see them here, too. A lot of misinformation out there and ways of trying to implement it. IMO, the best way is to use closed cell spray foam and condition the inside of the attic with HVAC. Even the codes are still being worked on and will change in regard to their implementation in the next few years.

1 Like is a great reference for information on this (and all things building science).

Ok, So the level of misinformation is unfortunate for us inspectors. My concern is on a ventilated attic, how do we prevent moisture with this method ? There are two different homes next to each other I inspected 2 weeks apart due to issues found in the first. In the pix you can see the roof vents on the one, and the second the soffit .

The builder is saying the insulation is Title 24 compliant. They agreed the vents were all blocked and repaired these two homes saying it was a fluke( yeah right), just looking for Any information on this supposed code for the way the roof insulated. I believe its so new no one has seen this yet and my client is asking how I can report on this if the builder is saying the opposite ?

Thanks For the Research !

More !!

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After skimming that PDF for the relevant info, I believe he is right.

There is another question about the ‘Radiant barrier’ or foil back roof decking. They are saying it used to also be required but no longer- however in that PDF it says Climate Zone 3 requires a radiant barrier…
I think I’ll reach out to the CA energy dept tomorrow.

1 Like

Good for you DJ. You put in much more effort than many of the inspectors that I’m familiar with. Seems like these days most inspectors search for an excuse to kick the can down the road and move on. I approach it the way that you do. Find the answer whenever possible and get your client the info they need.