Quote Originally Posted by mikenot View Post
I'd appreciate anyone who has single AAC block walls that have been rendered commenting on their experience with cracks.

What are you using for rendering the AAC ? the proper plaster mix designed for AAC, such as this :https://www.asiacement.co.th/en/bua-mortar-lightweight-block-plastering or the sand and cement mix as used for normal blocks ? If using the proper stuff you can get cracks if it is applied too thickly, it shouldn't be more than 1cm thick. I assume they used mesh over all the joins between columns, windows etc ?
Wot he said. Around here I see a lot more houses being built with AAC and in many cases they don't use the AAC mortar to bind the blocks, they just use the old cement mortar they know and love. That being the case I'd be surprised if they used the correct plaster mix. AAC blocks can absorb more moisture than the old blocks.
After 3 years I have two hairline cracks in my internal plaster. One is on the outside of a 90 degree corner, I suspect they didn't bother to overlap the blocks properly. The other is pretty much vertical in the middle of the bedroom wall, no buried conduits or anything there. I guess that is settlement of the foundations.