Replies

1. 
   architect64 | Aug 06, 2006 09:50am | #1

   Catskinner - any update on your AAC project?  Did you end up using e-crete?  I'm planning to build my home with AAC, and have been in contact with e-crete, but would like to hear about any actual construction experience from anyone in here.

1. 
   Catskinner | Aug 06, 2006 06:52pm | #3

   I ended up not using it, but I am still thinking about it.I've used many of the "alternative" materials and methods, and plan to continue, but I have learned to be cautious. The penalty (time, money, schedule, subtrades, unforseeen difficulties) that we pay for departing from the industrial module/model can eat all the profit in the job until you get to know the material.I think AAC is probably a good idea, but I'm not so sure the plumbers and electricians do.Thanks for bringing this up again. I'd like to bat this around some more and hear about the experiences others have had.

2. 
   CJD | Aug 06, 2006 06:07pm | #2

   I have not used AAC, but would in the right application. The big thing is to make sure about the R-values. Many manufacturers list big numbers based on "equivalent performance". Actual static R-value of AAC is about R-1.1/inch - better than R-0.1/inch for concrete, not too good compared to R-4.2 for EPS.

   The equivalent R-value numbers take into account near zero infiltration and thermal mass. Thermal mass is great if you experience daily fluctuations well above AND below your desired interior temperature. It does almost no good when you experience weeks where it is consistently above OR below interior temperature. In that case you are back to the static R-value.

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   Catskinner | Aug 06, 2006 06:57pm | #4

   Those do seem to be the primary considerations for energy efficiency.As interested as I am in mass-compensated thermal performance, and for as good as a result as I've seen, it is by no means a one-size fits-all solution.From what I've seen out of the NAHB, air leakage accounts for about a third of all heat loss.Also from NAHB, over 90% of all construction-defect related lawsuits are about moisture control.Seems to me that this AAC could be used to address many of these concerns, but we still have to be able to sell it for the price people are willing to pay.