# Insulation of Vaulted Ceiling



## Ferrino (May 5, 2013)

Hi all - first post here!

I have a vaulted ceiling in my double-garage which is unfinished and which I would like to drywall for aesthetics. You can see the underside of the plywood sheathing and then there is a series of 2x6 rafters. On the roof above there are curved tiles, common to Southern California (I'm in San Diego).

I was thinking that, although this is a shallow cavity, it might be a good idea to pack some insulation in there before drywalling, to reduce some of the intense heat that gathers in the garage in the Summer. Would that be a problem if the cavity is not ventilated? There are no soffit vents at the bottom of the rafters (and no vents at the top/ridge either). There is another similar vaulted ceiling above our living room and that is finished with drywall and I assume has insulation in it, yet it does not have any soffit ventilation either. 

Is the need to ventilate such vaulted ceilings a regional thing? Or is there some special arrangement of insulation required when the roof deck is not ventilated by soffits? I really an new to insulation and don't want to seal up the cavities only for the sheathing to rot out from condensation or something. I did read that soffit vents were an issue in California due to wildfires and the risk of embers flying into the roof deck through such vents.

Many thanks for any advice! Here's a ilnk to a pic of the exposed rafters I want to seal up:

http://imageshack.us/photo/my-images/36/rafters.jpg/


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## Ferrino (May 5, 2013)

bump :thumbsup:


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## Gary in WA (Mar 11, 2009)

Since it's not living space, makes quite a difference what you need to do with it; http://www.buildingscience.com/documents/reports/rr-1110-hygrothermal-analysis-california-attics

See map, pp.71; http://www.buildingscience.com/documents/published-articles/pa-crash-course-in-roof-venting

Gary
Ps. welcome to the forums!


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