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Adding new attac insulation over old.


plant4250's Avatar
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Join Date: Feb 2013
Posts: 9
OH

03-18-13, 06:31 PM   #1  
Adding new attac insulation over old.

I live in a 58 year old house that only has 3-1/2 inches of rolled in insulation with craft face. I want to add more insulation in my attic, I have been told that I can put new unfaced over the old but, It will be hard to put unfaced insulation over the old because you can't slide unfaced very easily into place over the old insulation and since I have a truss roof it will be hard to place the new insulation down in the eves of the roof if it can't be slid into position. If the new insulation had a craft face on it, it would slide over the old insulatio alot easier but I have been told I can't have two craft face one over the other. Are there a better way of adding more roll in insulation ?

 
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Nashkat1's Avatar
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VA

03-18-13, 07:13 PM   #2  
I live in a 58 year old house that only has 3-1/2 inches of rolled in insulation with craft face. I want to add more insulation in my attic, I have been told that I can put new unfaced over the old but, It will be hard to put unfaced insulation over the old because you can't slide unfaced very easily into place over the old insulation and since I have a truss roof it will be hard to place the new insulation down in the eves of the roof if it can't be slid into position. If the new insulation had a craft face on it, it would slide over the old insulatio alot easier but I have been told I can't have two craft face one over the other. Are there a better way of adding more roll in insulation ?
To find the optimum amount of R-value, and the amount of insulation you need to add, you can enter the information for your house into the ZIP-Code Insulation Program or a similar calculator.

3-1/2" does sound like less than an optimum amount. I would either roll out unfaced insulation over that or have cellulose blown in on top to achieve the R-value I needed.

No insulation should be placed in the eaves of a roof. The insulation should only be placed on top of the ceiling, inside the outside walls. The eaves need to be open to allow ventilation air to enter through soffit vents.

Technically, uncoated Kraft paper is not a vapor barrier. Kraft paper with an asphalt coating on the back, next to the insulation, is a vapor barrier. Check to see which you have now. And you could, in theory, put fg with an uncoated paper facing over that. I wouldn't, because I wouldn't trust its permeability, but the manufacturers and underwriters say it's OK.

 
plant4250's Avatar
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03-19-13, 08:33 AM   #3  
Thanks for the reply
I am like you on the subject on adding paper face insulation over what I have now. I will check with a company that does insulation and see what they suggest and reply back, Thanks again.

 
Bud9051's Avatar
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03-19-13, 09:21 AM   #4  
Hi plant,
I insulated a 4,000 sq ft building with 6" unfaced between the trusses for the first layer. To get them all the way to the narrow soffit area, baffels in place, I made a long pitchfork out of a 12' length of strapping with a 18" T at the tip. I then drilled and pressed 16D steel nails (nice smooth ones) into the T to complete my tool. Oh, and I added a triangular piece of flashing onto the bottom to allow it to slide out easily.

This allowed me to fold the end of the batt up and over the top so I could reach into each bay and flip that end out towards the soffit. It took a little practice, but once I got the hang of it the process went fast.

D get a quote from an insulation company for blowing in cellulose as they can often do the job for what you spend on materials.

Bud

 
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