When you say "code" which one are you talking about. Not all states follow the same energy conservation codes!
Are you talking about the "International Energy Conservation Code" by ICC?
You may also check this link for more energy-related topics and Q&A:
You can ask energy-related questions from this link:
Also, Ron Majette at DOE is a good contact for proposed changes and to see what is coming down the line relating to energy conservation. Here is his contact information:
Architect, Office of Building Technologies
U.S. Department of Energy
1000 Independence Ave, S.W.
Washington, DC 20585
Hate to be the "bearer" of 'bad' news, but there is a continuing insulation concern with cavity-only insulated walls, etc; and I am sure you are aware of it.
When you only insulate the wall cavities, for example, the wall materials continue to conduct heat/cold form the exterior to the interiors of buildings. Add in the higher conducting steel fasteners and reinforcing connectors/bracings/shearwalls, and there is a lot of gaps in the exterior/perimeter building thermal insulation. How these thermal conduits are insulated is a constant issue.
I am a firm believer that barrier-types of insulating methods are a more complete way to "seal" interior building temperatures and to prevent thermal transferring from the outside to the inside.
Since the current structural systems of rigid material building frames and components have too much natural building, component, and material allowable movement-s, you can't apply sprayed-on insulation, etc; solid coatings as frame-direct underlayments on either the interior or exterior surface sides of the rigid frame systems, leaving the Architects, etc; with limited choices in applying thermal protections to buildings and structures.
With a recently developed continuous frame and structure steel strapping reinforcing method and systems, the natural movements in the materials, components, and materials of the building's structural frame can be reduced/limited, which may allow for the spray-applied thermal barrier types of exterior insulations.
These thermal barriers are available currently, but are used primarily in deck and floor applications. The materials contain agents that are continuously flexible, provide a complete seal between the natural elements and the frames, and are usually spray-applied, a safer and easier way to install for the Applicators.
You can see more on my continuous reinforcing systems at my website: Tor-Eggs-Tor Design Solutions (most search engines), and I've put a few samples throughout this forum, also. In the "Sample Master-Planned Community..." webpage on my website, I've included a couple of sample illustrations of exterior wall sprayed-applied thermal, etc; coatings. These image photos are too large for attaching in this forum's replies (300kb limit.)
God Bless and Speed; Randy
My thoughts on ICF's stucco, and all wall systems that can get the rigid panel insulation boards in, are an improvement over cavity-filled only insulating methods.
When you look at the cost analysis, in relation to the overall construction costs, any added insulation increases a small percentage of the overall costs, so I defer these added costs to long term savings in the building energy savings. Just my personal take on the subject.
Although rigid board insulation is considered a "barrier" type of insulation, there are naturally, a lot of seams in the panels along an entire wall, both for installation ease and for what I mentioned above, as expansion joints for the allowable natural movements in rigid structure frame systems. With reduced, limited rigid frame system movement, I'm sure that spray-applied insulation technologies would be used instead of the rigid insulation panels/boards more often.
Spray-applied, as I have been taught, is the most economically efficient way to install/apply insulation, wherever it is located in or on the building frames, etc. If we can get the movement aspects of the buildings, from settling, mild winds, material aging temperature changes, etc; down to a quarter-inch, say, with a continuous steel strapping reinforcing method, more spray-applied location options open up on and in the buildings.
I specify a maximum of 1/16" to 1/2" allowable deflections in the various segments of Structural Strap-Nets, in both open-spaced and solid-wall frameing systems, that should be stable enough, year-round, for the application of spray-applied barrier coating insulations, to the entire exterior walls, including the horizontal "bird"-blocking above the walltop plates/beams between the roof trusses/rafters. I have to rely on the roof/truss framing Designer structural analysis to comfortably say that spray-applied barrier insulations could be applied to pitched roof exterior framing/decks, as an underlayment.
What do you think on reducing and limiting the year-round natural movements in structural building frames/systems? Could an Architect/Structural Designer add more Green and Sustainable Technology and Products, and save more interior building energy costs with what I am describing? I'd like to hear your general opinions on these.
Again, thanks for the interest on this topic, God Bless and Speed; Randy.
With spray-applied barrier-types of thermal insulations, the insulation Manufacturers can get more R-Value out of thinner insulating materials, and another R-Value facter, solid coating/sealing over an open/solid frame both can also add R-Value.
With less overall insulation materials, higher R-Values, and with more efficient installation/application methods, better stabilizations of the rigid structure building frames may be an overall economically, Green Technology, and LEEDS Certifiable way to design and construct buildings and structures.
God Bless and Speed; Randy.
At that time, the only way to achieve that R-20 with 2x4 wall construction was to add a layer of rigid wall insulation. Generally this was done with 1/2-inch foil-faced material on the outside with an air infiltration barrier sheet over it. In that norhtern environment a vapor retarder is usually placed on the inside face of the studs [warm side] to combat condensation problems. It definitely wasn't perfect, but it was the best we could come up with at the time.
The code was later revised and reduced to R-19 to allow 2x4 construction to meet the code without rigid insulation.
With the change to more acceptance of 2x6 construction in housing, this became a lot easier to deal with, then easier yet with the higher efficency fiberglass batts now available.
I guess a lot of people forget the "super insulated" houses designed in the mid-1970s [those darned hippies!] right after the oil embargo, where people where really insulating a lot [2x8 and even 2x12 fully insulated walls!] along with passive solar and extremely thick R-60 or even more roof insulation [and then venting above] developed... I remember some houses which were touted to be able to "be heated by the occupant's body heat alone"...
Thanks for your input. Yes it seems that everything old is new again. And, I love the idea that we could heat our home with our body heat. Those crazy hippies...