[Greenbuilding] [BULK] FW: Aerated Autoclaved Concrete

[Beatrice Dohrn]

1.  There are some other things to consider -- not that they are prohibitive,  but I think they are real to the ultimate users and builders of these houses.

- It's not hard to notch the blocks for wiring and switches, etc  but it does need to be done (there are various ways) and I think it gets overlooked in the analysis of how "easy" (cheap) the houses are to build.  It's time consuming whichever way you chose to do it,  and if you furr out the walls to make that stuff easy,  you lose some of the value the thermal mass if the system, as I understand it. 

-Attachment of whatever you'll want to attach to the inside, outside -- both in construction and also for the life of the house is a completely different animal than Americans are accustomed to (unless you lived in NYC prewar apts with plaster walls....which only a few of us have in our backgrounds) .  It may seem minor,  but I think it's something the enduser or the construction person who plans to finish out these houses needs to be aware of.   I've talked to some people here finishing up their aac house and it seems like some of this took them by suprise. 

2.  I am an owner builder about to build my second house near Eugene Oregon.  (First was 18 years ago , more like a cabin.)  I have designed for ICF's, with a little trepidation about the "cost" to the planet of this.  My choices are a little skewed by how different systems lend themselves to my personal abilities.  (i'm smart and I'm experienced as a cabinetmaker,  but I'm also 50 yrs old and weigh 135 lbs,  so I need to be able to work this project with a helper...)
 I am pretty convinced that an aac block house would probably be a better choice in a number of ways,  but I'm really not sure if I can build it comfortably bcause I'd need to use 12 inch blocks.  

THe aac people trash ICFs based on: 
1) leaking basements
2) gassy foam (sometimes suggesting poor air quality in house, sometimes it's about getting out if there's a fire)
3) bugs will infiltrate the foam.

I'm most interested in knowing if 2 & 3 (I assume 1 results from poor const.) are real world concerns.  The science suggests they shouldn't be,  but.....  Tell me what you know. 

Alan Abrams <alan at abramsdesignbuild.com> wrote:create a nice tight envelope, it's very lightweight compared to CMU, so has
a lower emboddied energy than most CMUs>


we've looked into this a few times too.  Rumors seem to waft by that a new
plant will open nearby soon, or an old plant closed down, etc.  that sort of
uncertainty, plus the cost and embodied energy of transportation for
relatively small quantities always seem to wind up as major limiting
factors.  also, I've read that the r-value of AAC is something like
1.2/inch, which we can more than double with good 2x6 construction.

Alan Abrams AIBD
Washington DC
www.abramsdesignbuild.com

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Beatrice Dohrn
541 746 1919 (h)
347 589 9053 (c)
       
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