One of the main advantages of the ICF consturction method is the superior insulation value of an ICF wall. But what do you do with the parts of the house that are not ICF, like the attic rafters? You can use blown-in or batt insulation, but a closed-foam insulation would yield far better results.
The well-known yellow expanding foam is a very good choice but lacks some 'green' elements and fire retardation values. Looking around on the vast interwebs, I came across a new option mentioned on www.icf-dev.com called 'Mineral Foam'. It is essentially a concrete mousse, filled with millions of microscopic air bubbles that puff it up to a shaving-cream like consistency. Mineral foam offers all the benefits of spray-foam insulation plus it is fireproof, it is inert with no off-gassing and has an R-value of 3.9/inch.
The R-value of Mineral Foam is 3.9 per inch, although its true benefit is much higher as it offers not just insulative resistance and airtight sealing as with expanding foam, but also it has thermal mass unparalleled by any insulation on the market today. Very ICF-like... ;-)
ICF-DEV.com suggests that mineral foam insulation be applied into roof rafters, where it fills all gaps and glues all structural members together for added strength which is needed during seismic events. It adheres on contact, forming an airtight seal eliminating infiltration currents --the number one source of heat loss-- helping maintain a comfortable, constant temperature.
When applied in the rafters down to the ICF walls, it encloses and seals the building airtight and renders the attic a 'conditioned space', conserving the energy normally lost by attic ducting and leaks through ceilings, and allowing you to put ducting, ERV, air handlers, etc up there.
Your ICF home with Mineral Foam can be so air-tight that it will qualify in this respect for the highest independently-verified certification standards, such as HERS, LEED Platinum, EnergyStar, and BuiltGreen five star.
Source of most of the info in this post: http://www.icf-dev.com/About_ICF/We_Recommend.php
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