Batt Insulation or Mooney Wall With Blown-In Cellulose
In reading GBA, I see a lot of attention paid to minimizing thermal bridging. One such technique is the Mooney wall, which, as I learned here, is 2x2s installed horizontally against 2×4 framing to create a 5.5″-deep wall with less thermal bridging than a 2×6-framed wall.
So, I’m going to insulate a 12.5′ x 8′ wall, which is only 100sf. The insulatable area is even less, because I’m installing 24sf worth of windows, and about 7sf of headers.
To install insulation into a Mooney wall, my understanding is my only option is blown cellulose, and renting a machine is a big expense and hassle for only 69sf or so of wall. If I attach the 2x2s to the 2x4s vertically, I could just install 5.5″ batts and be done with it, but I’d have more thermal bridging.
So, those of you who are serious about thermal bridging, if you were in my place, would you rent the machine to avoid the thermal bridging for a single small wall, or would you just accept the thermal bridging and install batts?
By the way, before anyone mentions, I’m aware that my headers have to be only 3.5″ deep, and if I go the batt route, I can glue 2″ of foamboard insulation to the headers. If I go with batts, then I do indeed plan to glue foamboard to the headers.
GBA Detail Library
A collection of one thousand construction details organized by climate and house part