# Open ceiling insulation



## Marleysworld (Jan 26, 2014)

I am building a Chalet style small house with an open, vaulted ceiling. Anybody have some good experience with insulating same? Many years ago I build a house in the pacific Northwest with a chicken coop style roof. I remember having to lift two by twelves into place to provide enough thickness for R30 fiberglass and drilling way too many holes to provide ventilation. As always my financial resources are limited.


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## jwal10 (Jun 5, 2010)

There are panelized roof sections that have the insulation sandwiched in the panels. You can buy wood I-beams, much lighter than 2"xs. You need more space in the joists than the thickness of the insulation so the air can enter the eave vents, rise and exit at ridge vents. Metal and 3 tab roofing have ridge vent systems....James


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## jhambley (Nov 21, 2004)

My home has a completed envelope of open cell foam in the walls and continuing up the rafters. In even the most extreme weather, I have measured only a couple degrees difference in the temperature at floor level versus at the peak of the attic (around 17'). Of course open cell foam isn't cheap but it is very effective. 

As you can see in the photo, my contractor foamed not just the space in between the trusses but also covered the truss members themselves to prevent any thermal transfer through the wood itself.


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## wy_white_wolf (Oct 14, 2004)

You can use foam panels on top of the decking. Did one a few years ago for a friend. 2 layers of 2.5" foamboard. Top layer had a 7/16 layer of OSB formed to it for nailing the shingles.

http://commercial.owenscorning.com/products/foam/

WWW


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## ErinP (Aug 23, 2007)

That's basically how we did our cathedral ceiling/roof; our trusses are exposed, then the layer of decking, then roofing felt, then 4" of polyiso, 2x4 strapping through the polyiso and into the trusses, then steel roofing tied in to the 2x4s. 









There's a current conversation about this very topic going on over at CountryPlans with several approaches and diagrams...


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## NorthwoodsMike (Jun 10, 2013)

We used these with fiberglass insulation on our vaulted ceilings.

http://www.menards.com/main/building-materials/insulation/accessories/provent-24-x-48-plastic-vent-chute/p-137194-c-5776.htm

Where are you building? Does building code require an engineer sign off? If so, you may be better off ordering roof trusses. Yes, they cost more, but it significantly reduces the amount of onsite labor and takes care of the engineering. It also gives you more space for insulation than 2x12's, and eliminates load bearing walls on the interior.


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## haypoint (Oct 4, 2006)

Simply buy scissor trusses. The inside has a lower pitch than the outer rafters. google scissor truss. Then insulate the best way you can afford.


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## jhambley (Nov 21, 2004)

If you want to have some type of exposed rafter look. I agree with Haypoint. Just order some scissor trusses and make certain they give you enough space to insulate to the proper R value for your area. I did that on a house in Texas and it was very comfortable. Just remember, the higher you go with that ceiling the harder it will be to heat the occupants. Ceiling fans will help but if you want to be reasonably energy efficient, don't go too crazy with the height.


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## MushCreek (Jan 7, 2008)

Look into SIP's (Structural Insulated Panels) They come in various thicknesses, and are part of the structure, not just insulation.


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