Exterior has the challenge of needing to flash deep window or move them out,
or replace them. Also in urban situations sometimes pushes setbacks and
property lines. Interior has the challenges of disrupting use, of getting
continuity past intersecting walls and floors, and of loosing space. One
solution is to spray foam the 2x4 cavity and keep the wall from growing much
If you have space to go out, and can deal with the windows, and want to be
in some ways greener, I would recommend you Google "Larsen truss" to see the
plethora of examples, mostly Canadian, and "modified Larsen" which will lead
you to other examples, more aimed at new construction, and several articles
and examples by Robert R.
"Environmentally Responsible Architecture, Planning, and Interior Design"
Jeff Schoellkopf, AIA, LEED AP
The Design Group
From: VGBN Discussion [mailto:[log in to unmask]] On Behalf Of Tim Yandow
Sent: Wednesday, March 10, 2010 8:29 PM
To: [log in to unmask]
Subject: Re: [VGBNTALK] Suggestions on Insulation retrofits
On the subject of green building, I am soon beginning renovation work on a
1960's home in Burlington. We are adding an addition to the south and west
sides of the house. The new envelope will be 2x6 with damp spray cellulose.
The existing house is 2x4 with fiberglass and the owners would like to
bottom up the house more, so we are thinking about adding a layer of
insulation to the outside of the house since all the old vinyl siding is
coming down and the windows all replaced (most of them have broken seals). I
am trying to figure out the best way to insulate from the outside and make
provisions for new corner boards and hardi-plank siding.
With polyisocyanurate, for instance, there is the problem of not being able
to add house wrap and needing to use longer fasteners for siding and to
secure window flanges. Or can strapping be used over that? Then there is the
issue of extension jams either inside or outside...I would love to know if
anyone has worked out a good solid system to do this. What I have read and
seen so far does not satisfy me. Thanks.