Insulation with spray foam

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Old 11-30-16, 11:46 AM
R
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Insulation with spray foam

Will the walls rot when using sprayfoam ? I live in Ohio and its pretty cold during winter and when its cold outside and hot inside I'm thinking there will be humidity in the walls and maybe its better using the glassfiber insulation instead ?

I'm living in an old two story house, ballon frame with partly knob and tube wiring. Need to look more into how much is left of that stuff. Think its partly replaced. Not sure.

If I am insulating with spray foam, can the walls be covered from the attic and down without tearing of the plaster walls ?

Thanks, I appreciate all your help!
 
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Old 11-30-16, 01:02 PM
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Properly applied, spray foam insulation will not foster mold or rot. Foam is much better at air sealing than fiberglass, which is an advantage for homes without good air sealing.

You cannot install spray foam over knob and tube. I don't believe any insulation should be placed over knob and tube.

I am not aware of foam contractors that will fill a closed wall cavity; it would need to be open to use foam. Blow-in fiberglass or cellulose can be used on closed wall cavities by drilling holes at top and bottom of each cavity.
 
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Old 11-30-16, 01:31 PM
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I don't believe any insulation should be placed over knob and tube.
This is my understanding as well.

Foam is a vapor retarder and can create a thermal break which keeps condensation from occurring, which makes it just about the opposite of what I think you interpreted it to be.
 
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Old 11-30-16, 06:04 PM
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First thing you need to do is get rid of all that old Knob and tube wiring replaced and bring all the wiring from the pole to the new panel up to modern codes.
 
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