I tried a search on Bautex block, to see if there were any discussions on the forums. Came up empty. Wondering if anyone has experience or educated opinions on these blocks vs ICF for residential construction in southern Missouri? Our property is 15 miles from the nearest volunteer fire department, so fire resistance is an issue for us. Our property is also heavily wooded and we average 48 inches of rain, so moisture and bugs (termites) are also why we are not wanting to build with wood. I have 4 years of planning to do before we begin any construction, so we are obviously in the early stages (although I have been reading up here and other places for several years already). Thanks in advance for any input. Tim Edited to add: one issue with ICF that has me still searching is the insulation on the interior wall. I am stuck on the idea of having the mass in direct contact with the air inside the house.

And sorry...but my paragraphs do not seem to be translating to the post! ugh

I built a house in Pa with low density concrete blocks, had a good experience and have a house that's both livable and attractive. Trouble is there are three ways to arrive at lightweight concrete and Bautex doesn't say which it uses, or at least that I can find. My guess is foaming -- chemicals that aerate the concrete as it's poured. (Cresco is another manufacturer.) Another approach is to mix EPS granules in regular concrete. (eg Rastra) The last, which I used, is to add a reactant to regular portland, causing it to puff up like a marshmallow, and cure it in an autoclave (pressurized steam oven.) (Aercon, Aircrete)The first two are aerated cellular concrete, or ACC. The last method is autoclaved aerated concrete, or AAC.
The Pros:
Low density concrete can be carved into anything an architect can conjure. I put chamfers, chair rails and entablatures on my house. It's a traffic stopper and, covered in a half-inch traditional stucco, as durable as, well, cement.

DIYable. You will make mistakes but building block by block they're going to be small ones that can be fixed unlike a nightmare in single-pour concrete.

Fewer steps, greater precision (possible). You can trowel plaster and stucco directly to it in the case of Rastra-like ACC or AAC but apparently not Bautex, which needs a moisture barrier.

In most jurisdictions you'll meet fire code with bare walls, which can be handled at your leisure.

Permanent by American standards. Fireproof. Quiet. Green. The first step in making cement is to heat limestone to 1000 degrees Centigrade. Obviously the life cycle energy picture improves for a block that's mostly air.

Cons:
Stackable blocks aren't really stackable. First off you need a near perfect first course or you'll be fighting everything that happens from there up. Even then, small discrepancies in blocks can add up to a major hiccup after four, five courses. Truing a wall in three dimensions is easier said than done I hired a moonlighting mason and served as his tender.

The cavalry is gonna be reluctant to saddle up. Bautex wants the blocks fixed with glue rather than mortar and suggest wood shims to keep them straight in three dimensions. Masons charge by the block and use a 3/8s mortar bead to compensate for irregular blocks. The good ones in action look like automatons. Your average contractor, even 10 minutes later, will be muttering "wood shims?" That said, masonry walls tend to be straight and true with 90 degree corners because there is much less room to fudge than with wood or foam forms.

You'll need old-school plasterers and stucco guys, I found some good ones who worked with Dad as teenagers back when every house got a skim coat. You'll need to skim every wall inside if you don't want a marked difference in appearance between block and drywall faces.

Bautex claims a static R14, but I'm wondering what the whole wall number would be after pouring the concrete honeycomb. Clearly it will be less efficient than regular ICF, or even OVE studwall with foam sheathing. On the plus side, it will be a tight house with proper attention to openings and ceiling.

Cost after shipping can be a problem. Rastra is in AZ. Aircrete is in Tx with a plant in Mexico.

I wouldn't pay a premium over studwall (and didn't.) You won't get it back in a resale.

Thanks for the reply and the benefit of your experiences.

One of the Bautex engineers is going to be in Houston several times over the next month. I am going to meet him for lunch and discuss my project.

You mentioned three manufacturing processes...but I missed why that is troublesome. I can certainly ask which method is used...but what is the problem with one or the other method?

Thanks,


Tim

I did notice in the Bautex videos that they use an aerosol can with some sort of foam/glue between the blocks.

And yes, they do recommend a moisture barrier. They sell (of course) both permeable and impermeable.

Open cell/closed cell is the major difference. AAC will absorb moisture but so slowly it doesn't need a barrier. Dunno about the Rastra approach. A second difference is tolerance. AAC blocks are cut and milled on the mating surfaces to a tolerance of a sixteenth inch after they come out of the autoclave. If Bautex is cast, you will definitely want to know what tolerance they guarantee. Finally foamed ACC is the one approach that can be done onsite in a single pour, albeit with specialized equipment rarely used in residential construction. That's why hybrid ICF like Rastra and Bautex comes in blocks at some considerable cost in shipping. I couldn't find a foamed concrete contractor. You might be luckier.
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I'd also look into poured concrete with rigid foam on the exterior.

Too much mass can be a problem outside the desert southwest. I have trouble controlling humidity with a minisplit set on dehu without making my house too cold. Except for the humidity it would be mostly comfortable without HVAC. Your results in Mo will vary. The alternative is a basement style dehumidifier that adds heat of condensation as it removes water. To be fair, controlling humidity can be difficult in any house tight and efficient enough to keep the ac off.
Consider cement block sheathed in foam or above ground versions of Superior Walls. The latter can be purchased in r21 panels.

Bautex is a Composite ICF, like Rastra, Apex, Amazon, performwall and Cemplex. Most are made with recycled EPS, but Bautex look like they use new, not sure why they would. A few of these have disappeared over the years. A few years ago I met with the owner of Cemplex in Pahrump NV, a few years ago. I like these ICFs and would like use them on a house without a basement and with stucco cladding. Otherwise I would use the more common flatwall ICFs like BuildBlock.