Insulation: Old insulation, plus adding new
I am a novice – have never fixed up a house before, but this winter I took the plunge into a new hobby and bought a little home to fix up and rent or sell.
The house was built in the 1940’s and I recently discovered they insulated with (full sheet) newspaper batts with a kraft paper outer layer (moisture barrier) . The house feels amazingly warm, even in the sub zero temps we’ve had in MN. And yet the previous owners had several space heaters in closets during our showings. I took down sheetrock in two bedrooms (outside walls) due to damage. I would like to add insulation to the walls with out removing the existing as they are quite tightly installed and I know there are siding nails everywhere underneath. I am getting conflicting recommendations on how to add insulation. Should I use batting with out kraft paper? Should I put up a moisture barrier after I insulate and before I sheetrock? Is there an air quality issue if I choose not to use the barrier? These are full walls that do not appear to have any previous moisture issue except directly around a window. I plan to Caulk well in that area.
Would appreciate any input on how to tackle insulating this area.
Bold North Builder
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Replies
Bold,
I must admit that I think that you may be in over your head. You describe yourself as a "novice" who has taken up air sealing work, insulation work, and water-management work as a "hobby." The results might work -- but then again, you might be headed for disaster. Most novices hire professionals, because an experienced contractor has years of study and experience to back up any job-site decisions.
The biggest red flag is this statement: "These are full walls that do not appear to have any previous moisture issue except directly around a window. I plan to Caulk well in that area."
Moisture entry at a window is the sign of a big problem. This problem cannot be solved by caulk. This problem is best solved by removing the window, then flashing the rough opening, and then either re-installing the window or installing a new window.
Here is an article you should see to get you scared:
All About Wall Rot
Here is a link to a video that shows you how to flash a window rough opening:
Window Sills That Won’t Rot