Well, it’s Hemp History Week. Here’s the short version of the industrial hemp rant:
If you think the US is a capitalist country, think again. We can buy all the industrial hemp products we want, but we can’t grow the raw material to make the products ourselves. Can you say, “trade imbalance”? To learn a bit more, watch these two short videos we were involved in that discuss industrial hemp generally and then specifically as it applies to our Nauhaus prototype:
The Hemcrete installation continued today in the freezing weather, and is up to the second floor. Ian Snider from Mountain Works dropped by yesterday to discuss some of the sustainably harvested wood he will be supplying to the project. Ian’s company uses horses to remove the trees that they selectively cull as part of a forest stewardship process.
If you’re interested in volunteering for the Nauhaus Prototype Project, please contact Billy.
Eco-Panels came out on Tuesday and Wednesday and installed the S.I.P. roof. The finished roof system for the Nauhaus Prototype will have an insulation value of about R80 when completed, because the spaces between the 8″ rafters will be packed with cellulose.
Some information about Eco-Panels, from their website:
For a truly superior building envelope Eco-Panels manufactures the only R60 panel on the market today coming in at just 8.5″ in thickness. This panel, designed specifically for use in arctic regions, is perfect for the passive house or net zero energy designs where most modeling software calls for an R40 wall and R60 roof (of course this will vary based on region). This roof panel will perform at better than R60 at 20deg F (-7deg C) using LTTP (long term thermal profile) and temperature vs k-factor performance data provided by the foam component manufacturer.
8 1/2″(21.6 cm) = R60+
Maximum panel length is 12′-0″ (360 cm) although this can be increased to 16′-0″ for large opportunities
Maximum panel width is 4′-0″ (120 cm)
The insulation is high-R-value polyurethane foam injected at a density of 2.5 pounds per cubic foot.
Eco Panels has a great explanation of what’s going on with all the new soy based polyurethane insulations.
…all polyurethanes are petroleum derivatives obtained by combining a polyisocyanate (iso) group with a polyalcohol (polyol) group. A great chemistry write-up on polyurethane foam can be found here. While polyurethane foam can take many forms, from car seats and mattresses to spray foam insulation, the isocyanates are relatively few while the “secret sauce” of the polyol can vary wildly from manufacturer to manufacturer and product to product. To cover up its petroleum heritage some companies call these components the harmless sounding “Part A” and “Part B”, and even give the finished foam product hokey descriptions like “…having anglefood cake like consistency”, but they’re all coming from pretty much the same or very similar chemistry.
Most people know that by fermenting fruits or vegetables you can derive an alcoholic beverage (think corn->moonshine, grapes->wine, etc). This can exactly be the alcohol needed for the reaction required to make polyurethane foam! In fact, the preferred alcohol in most of the polyurethane foam industry for the past 50+ years has been acquired from post-process sugar beets – the same sugar beets used to make table sugar. This happens to be the desired alcohol because it simply gives the best overall performance of characteristics that are important to the people that use foam. Flow (in application), adhesion, strength, insulation, etc., are just a few of the characteristics looked at.
Many companies experiment with their polyol (remember this is the “secret sauce”) to chase different desirable properties, and sometimes, as in the case of soybeans, the greatest property achieved is MARKETING. I’ve spoken with many large foam manufacturers and they’ve all tried soy-based foams but admit that quite frankly it does not insulate as well, or flow as well, or adhere as well as the sugar based foams. Sugar beets are natural and organic, and so are soy beans, so why all of the hype for soy?