200 + year old home with no insulation in walls
I will be removing the exterior sheathing and addressing air sealing & insulation from the exterior. Interior walls (plaster &wood lathe) are in good shape and the windows are not being replaced. I live in the Seacoast of NH. I plan to install plywood sheathing, typar, rain slicker (rain screen), combination of vertical grain siding &shingles. The part i can not make my mind up on is the insulation. I would rather not install exterior insulation although i realize that is preferred. I am not looking for passivhaus standards just to make the best of the space i have. I have in mind the direction I am leaning toward but would like additional feedback from all the great people here.
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Replies
Terry,
The most common choice for your situation would be dense-packed cellulose, which could be installed through holes drilled in your plywood sheathing after the sheathing is installed.
However, since you are opening up your stud bays, you may prefer to install spray polyurethane foam. It's your choice.
With the rain screen consider if the nailing patterns for the shingles and battens will allow you to use an arrangement of nailing strips to create the rain screen space, assuming there is room to do this with the existing windows. Using Home Slicker behind shingles can lead to a waffled look and some people have reported problems with nail bounces and wood splitting because of the resilient nature of the home slicker product(s).
No matter which rain screen system is used, you will need to give careful thought to how you install flashing around window and other penetrations, especially since you are not replacing the windows. I assume you are replacing or at least reinstalling the window trim...
Billy
Dense pack cellulose is a good choice in this case after the sheathing is replaced, however, we have experienced issues with dense pack blowing out plaster and lathe walls. As Martin said, SPF is an option, superior in fact, but far more expensive.
Dense pack fiberglass is also an alternative, and since it is installed at lower density than is cellulose to acheive equal thermal performance, the risk of blow-out on the interior side is reduced significantly. And, its also less expensive than spray foam.