Insulating from the outside in

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  #1  
Old 01-29-17, 11:52 AM
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Insulating from the outside in

There is another thread on the rejuvenation of our house in the siding section, but this is a insulation question.

Working on a house built in 1904 and we are redoing all the cedar shingles and original wood windows. With tearing apart some of the shingles I came across some termite damage and have for that whole section apart to replace any damaged wood. I have also come to find absolutely zero insulation in certain areas. This needs to be addressed as I go. I plan to pull all the cedar shingles off to enable me to despair any damage underneath and fix all the issues caused by someone installing vinyl siding. This opens me up to the possibility of only haveing the one by boards left on the house.

Win the original path and plaster on the interior side, it is not getting taken off. I can however remove the one by and access it from the outside.

So question is, how should I insulate it? Kraft faced? Unfaced? Kraft faced to the inside won't be able to be wrapped, but it would at least create some sort of aped barrier.
 
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Old 01-29-17, 12:11 PM
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Hi Rayn, is the board sheathing sealed tight enough (no major cracks) to allow blown in insulation? That could be installed with minimal tearing apart. If you encounter any knob and tube that will need to be removed before any insulation.

I wouldn't worry about a traditional vapor barrier, modern thinking is simply a vapor diffusion retarder and that can be your paint and plaster. Air sealing has become the more important upgrade.

I'll let others fill in from here.

Bud
 
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Old 01-29-17, 12:13 PM
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Drill 1" holes at mid span and at the top of each stud bay and blow in insulation using a machine that will usually come free of rent if you buy the insulation from the store. Blow in at the mid span until it is at that level, then blow in from the top. The midspan hole will allow air to escape until the entire bay is full. Now, you may encounter perlins, which will need to be addressed, since insulation won't go past them. Additional holes may be necessary.
 
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Old 01-29-17, 01:28 PM
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There are major gaps between the boards and they are loose. I plan to tighten them up as I go.

Any knob and tube is going to be replaced. I "believe" the main floor has been converted, but I know the top floor hasn't. Just going with blown in without fixing knob and tube isnt a option as the fire hazard created. Even blanket insulation won't work.

My main concern is the vapor barrier. If the plaster and paint work as that, then just adding insulation is doable. I can probably save a smidge and forgo the kraft face as well.
 
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Old 01-29-17, 02:01 PM
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Here is more information than you probably want, but I find it interesting when the building sciences admit they goofed, which they unfortunately seem to do a lot.
Do I Need a Vapor Retarder? | GreenBuildingAdvisor.com

Note he has a list of related links if you need more.

In his answer to the question "Can I just ignore vapor diffusion?" he identifies the colder climates where one might use a vapor barrier as the colder sections of Climate Zone 7, as well as Climate Zone 8, that is much colder than IL which is in climate zone 4 or 5.

Bud
 
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Old 01-29-17, 02:24 PM
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Interesting read! So I should be more concerned with air leakage then with vapor diffusion. Air leakage is a pain anyway and should be taken care of as the project progresses.
 
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Old 01-29-17, 03:28 PM
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Here's a link on air leakage that may add a few pointers.
https://www.energystar.gov/ia/partne...ide_062507.pdf
 
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