ICF versus AAC

[MarkP]

The driving force behind dry stack seems to be that it is easier, not requiring the skills necessary to lay up block in the traditional way. I have read however that if you try to dry stack blocks 8' high you will discover that the blocks are not perfectly square and that there is a lot of trying different blocks and putting them up only to take them down and spin them 180 degrees so that whatever slant is built into the blocks gets alternated and cancels itself out. The first course needs to get set in a bed of mortar to get a level start, then when you get halfway up it helps to set another course in mortar so you can start level again. There are savings but it is not as carefree as most references to the process on the internet would lead you to believe. While it may not require as much skilled labor it still requires a lot of unskilled labor and attention to detail. There is after all no free lunch. I am never theless very intrigued by the process as well as by conventional block construction, both with plenty of rebar and the cores grouted solid. I would be interested in straight poured concrete if there was a way for me to DIY. I have not read much about AAC construction. Does it provide its own insulation?

[ironyak]

For dry-stacked, the speed and ease is tied to the precision of the blocks. In areas with automated manufacturing with 1/16th inch variances the blocks fit like Legos. For here, where the blocks are apparently manufactured by half-blind one-armed hunchbacks resulting in curvatures you can see, the blocks need to be sorted and reoriented during stacking with at least one re-leveling course. Thankfully the grouting and SBC unifies and strengthens the final result.

AAC appears to be a good mix of features - lighter weight, thinset mortar, easy to modify, surface stucco finishes. Provides a lightweight concrete fill between the integrated structural columns and beams. Looks very DIY friendly and meets many of the material recommendations in A Pattern Language without all the form work and pumping.

8" thick AAC appears to have R-10 with good thermal mass so fine for many areas here IMO.
http://www.concreteconstruction.net/conc...h-aac.aspx

AAC would be a great option if available at a reasonable cost. I'll see what info I can gather from MHE and report back.

[john the architect]

SBC is a good product, and with that you can build with common CMU's. Might be a bit cheaper and keep open the option of adding actual structural reinforcing for wind and seismic.

John Maloney
310.562.0362
johnmaloney3@me.com
Hawaii Architect AR8082

[john the architect]

I have a cindercrete project ready to go requiring a stone-loving owner who wants some thick-walled award-winning architecture that is sustainability at an affordable price. Only cement wall building using this high percentage of locally sourced material. Can also develop approved plans for your lots on the Big Island.

John Maloney
310.562.0362
johnmaloney3@me.com
Hawaii Architect AR8082

[Luke Duke]

Just a follow up. Michael Hoffman told me via email thst their only business in the Big Island in recent years was a single shipment to a general contractor. Availability seems to be an issue on The BI.

I have looked into this question extensively. I see no good reason to favor AAC over Rob's Rastra ICF product. Both are superior to traditional materials. If we ever decide what we want to do, and if we do it on the Big Island, ICF will be our choice.

[Malapuaao]

I think this AAC is pretty ingenious stuff (soap + cement) and I saw a continuous mixer to make it [ https://en.wikipedia.org/wiki/Autoclaved...d_concrete ] on youtube [after 3:30 here https://www.youtube.com/watch?v=llsQL2bPWqY ].

Anyone else using AAC? Can I rent a mixer like that around here?

aloha

[Cagary]

quote:

---

Originally posted by Luke Duke

Just a follow up. Michael Hoffman told me via email thst their only business in the Big Island in recent years was a single shipment to a general contractor. Availability seems to be an issue on The BI.

I have looked into this question extensively. I see no good reason to favor AAC over Rob's Rastra ICF product. Both are superior to traditional materials. If we ever decide what we want to do, and if we do it on the Big Island, ICF will be our choice.

---

Here's a few photos of one of Rob's structures going up here on the Big Island.:

http://img.photobucket.com/albums/v61/Ga...kdjzac.jpg

-Veritas odium parit”(Terence 195–159 BC))-"Truth begets hatred".

[Cagary]

http://img.photobucket.com/albums/v61/Ga...jy4bx8.jpg

-Veritas odium parit”(Terence 195–159 BC))-"Truth begets hatred".

[bagada]

I have been researching this and there is even other things besides air that can mix into concrete to make it insulating. Lava cinders is one of them. The problem with these mixtures is that the more air you put in them, The less strong and the more insulating. You can use Perlite, Lava, vermiculite, and air(soap). Any mixture of those would also work. From what I read, Perlite and air are the most insulating but weaken the structure. Ideally, You would want to make a sandwich with more strong cement on the outsides and insulation mix on the inside. Lava cinders are the least insulating aggregate but also the strongest. Since lava cinders are cheaper than both perlite and vermiculite, It might be more cost effective to use it and just make the walls thicker to equal the R value of a better insulator. I think something like 14 inches of cinder crete is equal to a couple inches of perlite. IT seems that things that are very strong are not so insulating(concrete, metal) and things that are very insulating are weak due to having a lot of trapped air(down feathers, fiberglass fill). The sandwiching of insulation with strong wall materials seems like the best way to do it IMO. However, Cinders are very cheap, abundant, and local. Also the more concrete you add to the mix the more thermal bridging will happen through the web of concrete. FYI this is all theory.