Hey Pete,
I live in a straw bale home with natural earth plasters in northeastern Vermont that was essentially finished in 2011, but not using steel framing. We are at +44.5 degrees, and have many of the same issues you will have in Ontario as far as heating degree days (roughly 8,000 here, and about -25F this morning) and moisture issues which are VERY different than the straw bale houses of the American Desert Southwest! We re-used a 160-year old timber frame and built a straw bale "wrap" around that, with the entire frame exposed inside the continuous bale wall structure.
I hope you will take this as gently and kindly as it is intended... If you have been building with
traditional no,
conventional building materials and methods for many years, you may have to re-think some of the conventional wisdom that has served you well for so long. More specifically, there could be a number of issues integrating lots of metal elements into a bale wall system, since metal surfaces can be cold surfaces or thermal bridge elements that could cause condensation and moisture management issues if you haven't really approached your design details from all the angles. In other words, some things that work well in classic "stick-built" or metal framed buildings may not work real well in a natural building strategy like straw bales (or
cob, etc...)
Most of the design and construction
books tend to apply mostly to building straw bale structures in warm, dry climates, and there are many small details that have to be adjusted to work well in a cold, damp climate. One of the best classic construction books that covers building in different climates --
Serious Straw Bale, by Paul Lacinski and Michel Bergeron, is now getting out of date, since so much has been learned about building for colder or wetter climates (and I hear Paul no longer builds houses full-time, though he trained a lot of builders in the Northeast, and built a house for a friend of mine in a nearby town. As an example, wrapping the bales in
chicken wire is no longer considered beneficial, though many books tell you to do it.
Brand-new, completely up-to-date, and very detailed, is the
Natural Building Companion-- A Comprehensive Guide to Integrative Design and Construction, by Jacob "Deva" Racusin and Ace McArleton of New Frameworks Natural Building, in Northern Vermont. They are 2 of the 3 natural building experts that worked on our bale wall system, good friends, and expert teachers. The book is not cheap, but will definitely be well worth the price in all the mistakes they will help you avoid! Ace & Deva also teach at the Yestermorow Design Build School (also in Vermont)
http://www.yestermorrow.org/, where you might learn more on these topics.
Ace and Deva, as well as Ben Graham, of Natural Design/Build have also done extensive testing of natural building methods, so they have used infra-red cameras, blower door analysis, and have otherwise applied modern science to address the anecdotal claims about efficiency, air quality, air sealing, etc... If you want to get it right, I can't recommend the book -- or one of their classes -- highly enough.
Info on the book is found here:
http://www.chelseagreen.com/bookstore/item/the_natural_building_companion/