# Insulating Low Pitched Roof with Vaulted Ceilings Inside



## Windows on Wash (Aug 30, 2011)

How tall is the interior ceiling?

Best bet is to probably put up some rigid foam and re-drywall.


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## BlakeL (Jul 30, 2012)

Windows on Wash said:


> How tall is the interior ceiling?
> 
> Best bet is to probably put up some rigid foam and re-drywall.


The lowest point is 8' and the highest is 9'. Is there an easier way that doesn't require tearing down the drywall?


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## BlakeL (Jul 30, 2012)

Any other idea of how to fix my problem?


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## Windows on Wash (Aug 30, 2011)

Is that joist space vented? 

You could dense pack that area but doing so will convert it to an un-vented assembly and that can be problematic.


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## BlakeL (Jul 30, 2012)

Windows on Wash said:


> Is that joist space vented?
> 
> You could dense pack that area but doing so will convert it to an un-vented assembly and that can be problematic.


Yes, each joist section is vented at the end. There is no venting at the peak. The issue I see is the vents are only 2" holes with mesh so the inside ceiling still get's really hot. I know installing a vent at the peak might help but that seems harder than blowing insulation up in between each joist. I'm assuming for blown insulation that I would just need to get a long tube but the problem would be the scissor supports about half way up. 

How are most of the houses like this insulated? I see many small block houses with very low pitched roofs or flat in Central Florida and Miami so they have to have something between ceiling/roof.


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## joecaption (Nov 30, 2011)

Another way is with SIP roofing panels. Since you have little money and the roofs in good shape this may be out but it would add a whole lot of insulation value and save in the long run on cooling cost.
http://www.insulatedbuildingpanels.com/


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## BlakeL (Jul 30, 2012)

joecaption said:


> Another way is with SIP roofing panels. Since you have little money and the roofs in good shape this may be out but it would add a whole lot of insulation value and save in the long run on cooling cost.
> http://www.insulatedbuildingpanels.com/


That looks like a good solution but I doubt I could afford it. I can probably only afford around $700-1000 for this project.


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## Gary in WA (Mar 11, 2009)

Do not dense-pack cellulose in it. Are the HVAC ducts in there?

Gary


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## BlakeL (Jul 30, 2012)

GBR in WA said:


> Do not dense-pack cellulose in it. Are the HVAC ducts in there?
> 
> Gary


No, there are no a/c ducts running through it. What would you recommend?


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## Windows on Wash (Aug 30, 2011)

BlakeL said:


> No, there are no a/c ducts running through it. What would you recommend?


What I said earlier.

Foam to the interior wall and re-cover with drywall.

Leave it vented.


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## BlakeL (Jul 30, 2012)

Windows on Wash said:


> What I said earlier.
> 
> Foam to the interior wall and re-cover with drywall.
> 
> Leave it vented.


If I did go with rigid foam board, what R value/Thickness would you recommend. Also, would increasing the size of the vents help any? 

What is the main issue with packing in cellulose insulation?


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## Windows on Wash (Aug 30, 2011)

BlakeL said:


> If I did go with rigid foam board, what R value/Thickness would you recommend. Also, would increasing the size of the vents help any?
> 
> What is the main issue with packing in cellulose insulation?


The more the better. Code would likely call for R-38 which is going to be 6" of Poly-iso.

Dense packing cellulose can create a moisture and rot issue.


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## Gary in WA (Mar 11, 2009)

It sounds as if you have "scissor" trusses? Is there access/room to crawl around up there? Describe, please.

The roofing is a vapor barrier to d.p. cellulose; http://www.buildingscience.com/docu...archterm=attic+fiberglass+batts+in+flat+attic

Gary


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## BlakeL (Jul 30, 2012)

Gary in WA said:


> It sounds as if you have "scissor" trusses? Is there access/room to crawl around up there? Describe, please.
> 
> The roofing is a vapor barrier to d.p. cellulose; http://www.buildingscience.com/docu...archterm=attic+fiberglass+batts+in+flat+attic
> 
> Gary


I'm back to trying to figure out this issue since the summer is upon us and our A/C is running constantly. Our whole roof is similar to the image below. We have the roofing surface, deck, then open space which is probably only 6-8" x 12-18" between each truss and then the drywall for the inside. There is no insulation where the picture shows it Between each truss there is a vent similar to the picture. People have recommended taking down the drywall inside and adding insulation which we don't want to do. I'm wondering if just rolling on one of those white roof coatings that reflect the heat will be enough.


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## Gary in WA (Mar 11, 2009)

If the coating worked you would see many many more white colored (coated) roofs... vent the roof (add ridge vents) and insulate to minimum code requirements for your location (R-30) http://publicecodes.cyberregs.com/icod/irc/2009/icod_irc_2009_11_sec002.htm 

More on unvented, expect a 10% service life reduction for asphalt shingles; http://www.buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation?full_view=1

Hot climates; http://www.buildingscience.com/documents/reports/rr-9801-vented-and-sealed-attics-in-hot-climates

Check with your local AHJ, venting may be required.

Gary


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