Has anyone here ever used Hebel block? It is the North American version of the wildly popular Ytong autoclaved, aerated block. It claims an equivalent R valve of better then 60 for a 10" block (I have to look into this more). I have a German friend who wants to build here in Toronto and is considering filling a container with the stuff to ship over.

I built my house with AAC block purchased from Aercon AAC in Haines City, FL. At the time Hebel's US arm, Xella Aircrete, was manufacturing block in Adel Ga. Xella has since closed that plant, and supplies block from a plant in Mexico. Neither spot is exactly next door to Toronto. My house arrived on two semi flatbeds for a shipping cost of $3k. The major limitation on compositive ICFs and tiltup SCIP is shipping expense, and the problem with shipping is fuel. Back when, neither company used rail. Seaborne container didn't occur to me. It could work from England, say, where construction is in sorrier shape than here, and shipping often involves ships.

Some clarifications: Mid-density AAC (500 psi) is a steady state R1.25/inch so the typical 8" block is R10. I showed my BI Hebel studies indicating a mass-enhanced equivalent R value of 17 for the Washington DC climate, which is pretty close to mine, and met the 2006 US energy code (but not 2009 and later.) R60 would take a lot of block in Toronto, which isn't exactly the best climate for mass effect. Of course, you can sheath it in EPS, or hang AAC planks curtain-wall-style on conventionally insulated structural walls

On the plus side, bare AAC meets US fire standards without drywall. I parged plaster inside and conventional stucco outside. It is eminently DIYable with only a box store cement mixer. Or a relatively easy adaptation for conventional masons. Good sound qualities. Completely malleable from a design standpoint. Longevity of concrete.

Dunno if you are familiar with Toronto-based Durisol, a manufacturer of composite ICF blocks with most of AAC's characteristics.

I have seen a number of houses built with Durisol and I like the block. Not sure if I would build with it though but I don't really have a reason not to. Interesting that the german Ytong website states the heat transfer value(U) for a 240mm block is .27w/m2K or, if I have changed it over properly, .048 btu/hr/ft2 which would equate to an R55.

The problem is the same with the double brick houses we have here. The R value would be somewhere around 8 but the performance is similar to a R16 or more house. Buildings departments have trouble accepting the data. I wonder if they would make us add 4" of foam on the outside?

Block with vertical holes about 1" apart and about 6" of foam on exterior side of block is common in Austria /Germany. They are saying R57 possible using the block with vertical holes off set. Thermal Mass/ Thermal break