Faced or Unfaced in California?

Up here in Reno we use insulation with the vapor barrier. I talked to someone I know in the Bay Area part of California and the guy was installing unfaced insulation. When asked the guy didn’t have the answer why he was using unfaced. Is this common in CA?

Need more info as to the application. Different applications, different product.

Walls and Celing of a stucco house. Old part is 1925 gutted with a new addition. Most of the attic is R-30 and vaulted. Walls R-13.

Generally no Vapor barrier here in Attics

Vapor barrier usually depends on the climate zone.

In climate zones1, 2, 3, 4A, and 4B a vapor retarder is not required regardless of the use of exterior insulation

I’ve always used insulation with a facing for exterior walls and ceiling, it’s so much easier to install then un-faced and the facing moisture barrier provides some protection. The only un-faced I would typically use would be blanket insulation or loose fill, unless it was for noise reduction for interior walls. Also depending on exterior siding applied I may also use a poly-encapsulated insulation.

the generalized map may mislead

And that generically is ok, but, on what side of the wall do you install the barrier? It makes a difference.

Contrary to what some may think the batt facing (Kraft paper/moisture barrier) should face towards the interior space, unless local building codes specify otherwise.

With the inclusion of your disclaimer (unless local building codes specify otherwise), you are technically correct, therefore,** if **craft faced insulation is installed it should be installed towards interior space (per manufacturer’s). **BUT, **installing craft faced insulation is not always the proper method. Different climates, and even micro-climates can dictate different insulating material methods.

Bottom line is… the answer to the OP’s question is not as “cut and dried” as he was led to believe. There are many factor’s involved to properly insulate a home.

Not true, it depends on location.

On What Side Should the Vapor Retarder be Installed?

In areas where the climate is cold in the winter, the vapor retarder should be installed inward toward the warm living space — or on the warm side in winter. In humid climates or areas where there is extensive use of air-conditioning, if a vapor retarder is required, it should be installed on the exterior side of the wall.


I agree, regional climate conditions do make a difference on how and what type insulation is installed.

That’s why I added “unless local building codes specify otherwise”
I understand as a home inspector we are not code enforcers, but we still need to know the correct install used in our areas.

Here is Missouri, every time I see a vapor barrier on a ceiling, the drywall against the barrier has mold on it. Vapor barriers on ceilings do not make sense to me.

Relatively common, yes. I find it both ways (w/barrier and w/o barrier) equally on newer construction.

I know it’s not required for there zone but it’s not prohibited either. The North American Insulation Manufactures Association say Kraft faced can be used in all climates.