[Greenbuilding] How green is cellulose infill? / thermal bridging?

[Alan Abrams]

<When I did some modeling of thermal bridging in a standard 2X6 wall, I
came to the conclusion that a thick layer of foam insulation (1" or more
- I've used as much as 1.5") is a good practical way to limit the
effects of thermal bridging.  The second way is to use Advanced Framing
techniques, which reduce the stacks of framing members at places like
corners or intersecting walls.  >

as an earnest student of residential building science for the past several
decades, I've concluded that for conventional stick framed walls, the first
task is water management.  And foam sheathing --without disproportionately
complex furring, flashing, extension jambs, caulk joints, and other assorted
band aids and potential leakage points--compromises that task.  This comment
is based on real world experience, with real world conditions.  All the r
value in the world is worthless if the walls leak.

If it's true that a continuous layer of insulation is critical to thermal
management, it makes more sense to me, to put it on the inside of the
wall--perhaps even strapping 2x3's perpendicular to the studs, so the
bridging is limited to 1 1/2" square points.  Let the outside surface be as
simple and straightforward as possible, to manage water.

Wrt to advanced framing, I've been doing much of it for years before it had
a name.  driving the carpenters nutz, too, doubling band boards instead of
conventional headers, drywall clips, single sill plates for windows, etc.  

Alan Abrams