[GSBN] [nbne] no Timber frame for Alberta house

[Kelly Lerner]

HI all,
Just chiming in to say that ground coupling (with insulated crawlspace OR slab on grade with excellent perimeter insulation and insulation below based on climate, soil conditions and heating system) is clearly a more energy efficient choice in a cold climate, because the delta-T at the soil is always going to be less in the winter. That means less heat loss at the floor/foundation. Ground coupling also helps with summer cooling if that is an issue in your climate. 

Also, heat loss through soil is highly dependent on moisture content. A wet soil will conduct heat very quickly, while a dry, well drained soil conducts heat slowly. So like every other design decision - the best solution depends on the very LOCAL site conditions and your own design priorities - cost, esthetics, available materials and labor, energy efficiency, etc. The human mind can make up logic to justify almost anything that the human heart wants to do.

With that said, I think a strawbale wall integrated with let-in, light-weight post and beam (4x4s flanking windows and doors and at the corners) would be both the most material thrifty (small pieces of wood and not too much of it) and the most wind resistant (more than a timber frame with all those somewhat flexible connections). The California testing (documented in "Design for Strawbale Buildings") shows pretty impressive wind resistance. Just my two cents worth. 

Great discussion!

Kelly


On Sep 18, 2011, at 12:53 PM, Laura Bartels wrote:

> I'm out the door to a wedding so can only offer a brief note right now (maybe some of you know Matthew Harris, who has worked at SEI for years and also worked on some sb project in CA, including one of Kelly Lerner's. If you do, congrats are in order). To explain a bit more about the Buffalo House design, it uses crawlspace design because that is the most common in the area. Most of the HUD "core" homes have crawlspaces. During design charrettes, it was determined that the design should stay somewhat recognizable in form, with improvements to layout based on earlier charrettes held by COUP, that the construction style (besides the whopping change to straw bale) should still be somewhat familiar so that it wasn't "all new". However, the crawlspace was modified by being insulated on the exterior of the stem wall and footer with 4" of XPS per shallow frost protected specs for this climate zone. Kelly Lerner may want to chime in on anything additional as she helped with this as well. 
> 


Kelly Lerner, Architect
One World Design Architecture
509-838-8812
www.one-world-design.com

Have you read Natural Remodeling for the Not-So-Green House? Available in Bookstores across the Universe. 
www.naturalremodeling.com



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sustainablesources.com/pipermail/gsbn/attachments/20110919/5845909e/attachment-0001.htm>