Replies

1. GBA Editor
   Martin Holladay|Sep 25, 2017 04:30am|#1

   Ethan,
   You don't need a rainscreen gap on the wall you have described.

2. Expert Member
   Dana Dorsett|Sep 25, 2017 08:08am|#2

   Be careful in your cement board product selection- many cement board products aren't rated for exterior use, and can suffer freeze/thaw damage in a zone 5A climate. Fiber-cement siding with a factory applied stucco-like finish is fine, but only above grade.

   Rock wool can wick moisture, but the AAC won't (much). what will the interior finish be?

3. 
   Steve Knapp CZ 3A Georgia|Sep 25, 2017 08:19am|#3

   Ethan,

   Have you checked on availability for AAC is in your area? I've also read that some manufacturers have reservations about using it below grade.

4. 
   Ethan ; Climate Zone 5A ; ~6000HDD|Sep 25, 2017 10:45am|#4

   Thanks everyone...

   I am not intending to do any of this below grade.

   Regarding AAC availability, I have previously been in contact with Aercon - and got some pricing - though I'm not sure if the hurricanes affected them.

   I will look into the appropriate exterior grade cement boards. Do you know of any that are good for exterior use?

   My thoughts on interior of AAC would be vapor open stucco/plaster finish with all electrical in conduit.

5. 
   Ethan ; Climate Zone 5A ; ~6000HDD|Sep 25, 2017 11:34am|#5

   Martin, would you feel the same way if I were to replace the rigid insulation outboard of the AAC to EPS foam?