Replies

1. 
   Jim_White_AIA | Nov 02, 1999 10:27pm | #1

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   Tom, our firm has looked at this product and we feel that it has tremendous potential, especially in Texas. The positive effect of thermal mass, good insulating qualities, breathability, load-carrying ability, amd easy workability of this material more than justify the slight increase in costs compared to conventional stick framing. When we went to look at a custom residence being built locally with this product, it so impressed the retired master mason we have on staff that he is planning on using it for a new personal residence, as am I. You might contact Hebel SouthCentral at (972) 735-9133 and ask for more information, or contact their regional sales manager, Mike Fletcher at [email protected]. If I can be of any assistance, please feel free to contact me directly.

1. 
   Norman_Williams_GREENBLOCK_METRO | Nov 03, 1999 08:00am | #2

   *Hi Tim, There are a couple of Hebel houses going up in the subdivision I live in just south of Dallas. Contact me and I'll be happy to introduce you to the contractor. He is a friend of mine.

1. 
   Jack_Durre | Nov 04, 1999 12:49am | #3

   *Hey! Keep this topic going! I too, am looking at Hebel (now known as "Matrix") for my own house in So. Georgia. I've been fascinated by the information I've turned up to date, and it just seems to keep getting better. One of my most recent questions had to do with the use of a vapor barrier with AAC (it's "Autoclaved Aerated Concrete", by the way), and the advice I got from several different sources said 'no-none required'. That's one more small cost that I won't have to pay as compared to frame or conventional CMU. Another advantage, if you consider veneer plaster on the interior has to do with plate height. I'm looking at a minimum of 9 feet, and in frame, that means extra cost due to waste of longer studs, sheetrock, etc. With AAC, I can stack it to the desired height and apply the veneer plaster without concern. (I'm also considering it for the interior partitions, since my nearest fire department is 45+ minutes away! This stuff has an 8-hour rating.) Anybody have any experience with veneer plaster in this situation? (I've had it on drywall, and loved it, but this is a different situation/material.)Somebody tell me what's "bad" about AAC...I'm getting worried, because I haven't been able to find much to date!

1. 
   timbo | Nov 06, 1999 12:07am | #4

   *Thanks for the imput, Jack. I've not thought about the advantage of the ACC in 9'+ ceiling heights -- good point! I wonder though how the ACC block building method compares with stick construction. I've mentioned this type to several builders in the area, and they're rather cool to it. Probably because they are not geared up for it, i.e., know subs who are competent in this, and they won't be bothered in this builders market. You've probably read the other replies that I've received, and I plan to contact these guys, too. Let's keep in touch about this method. I'm equally excited about building with the blocks. I wonder how they handle thru wall wiring, cable, plumbing, etc? I may travel to the Dallas area to see these homes going up (see previous message)and talk to the builders and owners if I'm able to get away in time to see them.

2. 
   Guest_ | Nov 07, 1999 10:43am | #5

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   Don't have time to research this more now, but a couple of things I did dig up:

   For those of you who like technical documents, you can plunk down $25 for 4 pages of: "C1386-98 Standard Specification for Precast Autoclaved Aerated Concrete (PAAC) Wall Construction Units" from the ASTM at:

   http://www.astm.org/DATABASE.CART/PAGES/C1386.htm

   There is an article in Environmental Building News on Autoclaved Aerated Concrete (has short list of some vendors):

   http://www.ebuild.com/Archives/Product_Reviews/AAConcrete.html

   Another brief overview of AAC in Advanced Buildings - also lists some manufacturers. A couple of quotes lifted from there:

   "Experience and Application:
   Hundreds of homes, primarily in the southern US, have been built using AAC. In this climate, AAC increased comfort levels and lowered energy costs for the owners. The performance of AAC in cold climates and commercial buildings is not well documented."

   "Cost:
   At least one US manufacturer claims that the houses constructed with exterior AAC walls cost 1 to 5% more than a conventional wood frame houses."

   http://www.advancedbuildings.org/aercon.html

   A press release(?) of another vendor at:

   http://www.newcretellc.com/index.html

   "New Crete LLC has joined forces with Texas Contec, Inc. to promote a better building material for the construction industry - Autoclaved Aerated Concrete."

3. 
   Jack_Durre | Nov 08, 1999 12:06am | #6

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   Timbo:

   I just received the tech manual from Hebel at the office on Fri., so I haven't had much time with it as yet, but I can answer one of your questions:

   Electrical and plumbing...it's so simple, it's a bit hard to believe, but if you find the right (read: open-minded) sub, you're home free! To run an electrical line, lay up the wall first, and then simply pull out your woodworking router, chuck up a core bit, and plow a groove into the wall face from point A to point B. Pull (maybe that's a misnomer in this case!?) your wires, patch the groove with the appropriate patching material (supplied by the AAC mf'r), and you're done! (Unless, of course, this was a previously-finished wall, in which case, you'll have to patch the veneer plaster, sheetrock, panelling, or what have you!) Simple, yes?

   As I understand it, the block should NOT be placed below grade (monolithic slab/footings or CMU stem wall), although I haven't actually seen anything saying so. Once the block is laid (and these can also be panels, BTW. I'm looking at using an 8" x 12" x 24" block, laid as an 8" thick wall...makes 2 sq. ft. at a time for 38 pounds of weight...almost the same as conventional CMU), and the mortar is apparently Type S or M, you need to place windbracing in the form of tie bars back to the footing. The easiest way appears to be to stub up when you do your foundation with rods at spacing/locations determined by code/engineer. You would then rout out the block/panels as you lay them up, so that there is a continuous path up to the tie beam. The tie beam can be a lintel block, and the rods would then be brought up from the stubs to the beam through the routed grooves. Bend over the top end into the lintel's channel, grout the lintel and the routed grooves, and you've got a wall!

   To a framing-oriented contractor, this probably sounds scary, but again, if you can find an open-minded one, he's likely to find that it's quick and relatively cheap. The info that I'm getting says that it's "close" in cost to frame, and the payoff makes it cheaper, if you amortize it over 30-50 years. (No vapor barrier, lower heating/a/c costs, no termites, etc.)

   I've gotten a couple of names of experienced subs in my neck of the woods, and they should be able to give me more names of electrical, etc., so that I don't have to pay for their education! You may be able to do the same, since there's a Hebel plant in Texas, and they're bound to have a rep working the surrounding area. He can provide you with the names, just as my rep did for me.

   Good luck! (Do I sound like I've reached my own decision here? )

4. 
   Guest_ | Nov 08, 1999 02:08am | #7

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   We build exclusively concrete homes, usually with steel framing. I have been asked by several of the builders that we subcontract from to use the Hebel system. (BTW there are several and prices vary greatly) I have shyed away, mainly because of the time and expertise required, the block must be set by competent masons, and the mortar must be mixed by same. We elected not to get involved with one, and a regular mason did, he had fits when he had to start accomodating all of the requirements that the builder and homeowner had, it took weeks to do the job, when everyone involved thought it would be up in a snap.....simple things such as Lintels became major issues concerning loading, etc. Moral here is find someone that has BEEN THERE, DONE THAT. I think the fire resistance etc. is great, but I still believe that if you go to the extra expense, wouldn't you like to have a house that will withstand a tornado? and have a performance R-value in the R-50 range?.....don't get me wrong, I think they are neat, and have looked into using the panels for floor systems with regular ICF walls, I just wonder about the cost vs benefit for exterior walls..... BTW, I have a builder customer in Austin that will give you a good (maybe biased) opinion on both Insulating Concrete Forms (ICF) and Hebel, he has done both. I do know you might as well throw the router idea away, go buy a cheap $40.00 electric chainsaw at either Home Cheapo, or bLOWEs, don't add any chain oil, and rout away, you will wear out the chain, but you will also make cuts at lightning speed compared to the router. Ian

1. 
   Guest_ | Nov 08, 1999 11:37am | #8

   *Ian,How would the chainsaw work on typical ICF?Jerry

1. 
   Guest_ | Nov 09, 1999 04:35pm | #9

   *Jerry: We use electric chainsaws all the time, they are great compared to the hot knives and routers. They make a mess, but you can soon become a "qualified, certified FOAM CARVER". Try it once, you will never switch back.....and start practicing, we will be having the foam carving contest sometime next year!! Ian....seriously, if you have questions, don't hesitate to contact me. If you are in the TEXAS area, you are welcome to come see a project or two, even get paid to work on one. Ian

5. 
   Jim_White_AIA | Nov 13, 1999 12:09am | #10

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   Ian, I love your electric chainsaw recommendation. You must have been a remodeler in a past life...
   Anyway, using a skilled tradesman may not always be the best route with a new product like this. Only the first course is laid using Type "S" mortar. It's critical that it be laid plumb & level, but that's not all that difficult. After the first course, subsequent courses use a notched trowel and special high-strength mortar for the bed & head joints. If things get grossly out of wack, you just cut a tapered AAC shim, slap it in the wall & keep on going. It is really amazing what you can get away with appearance-wise compared to a normal masonry wall and still end up with a sound wall. I know that Hebel has pre-engineered lintels available & can probably make custom ones on order.
   It would be interesting to find out if Texas Tech's engineering Dept. has come up with any tornado resistant designs using this stuff. I suspect that it would just suck up wind-born objects from a tornado like a bulletproof vest, but I really don't know. Mt next home WILL have a tornado shelter. We've dodged that bullet one time too many...
   Using metal framing for the non load-bearing walls is an excellent idea. Have you costed-out gypsum lath w/ a skim coat of plaster on everything instead of gypboard? With the fire ratings for this type of construction, a homeowner just might be able to get a discount on their insurance. 20 min. rated doors probably wouldn't be cost-effective, but everything else sure looks like it might qualify as at least 1-hour rated construction.

6. 
   Tim_McCloskey | Jan 04, 2000 11:32pm | #11

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   I'm considering building a house using the Aireated Conclave Concrete (sp?) blocks that I was reading about in last years' Fine Hombuilding magazine. Has anyone used this before? I like the idea of plastering the inside, but wonder if the overall costs of using the block is significatly higher than traditional wood frame/drywall construction. I will be building my home in the Central Texas area if this helps. Anyone have any knowledge about this? I will really appreciate any replys.

7. 
   varunsharma960 | Nov 28, 2021 04:30am | #12

   ACC stands for Autoclaved Cellular Concrete, which is another name for Autoclaved Aerated Concrete (AAC), a light weight concrete material that does not use coarse aggregate. Aggregates used for the manufacture of this concrete is no larger than the size of sand particles.

   Approximately 80% of the volume of an ACC or AAC block is air, and this is achieved by foaming of the mix.

   The main constituents of ACC are Lime and/or cement, sand, fly ash, calcined gypsum and water. Foaming is achieved by the addition of aluminium powder at the rate of 0.05–0.07% by volume. https://www.helplinehub.org/acc-cement-customer-care-number/
   Autoclaving is the process where an object is subjected to steam at high temperature and pressure in a chamber or device called the autoclave. However, autoclaving chambers for AAC blocks are large and several units of these blocks are autoclaved at the same time. Autoclaving results in the strengthening of the ACC block.