Hi, it's me UREdogLady. If you were following Cheap and efficent you know my inexperience.Since Jelly advised a new tread I decided to try it. Alot of site considerations, insects and moisture foremost then theres unpaved roads and rear elevation, this is what I have been considering AAC blocks w / CMU base on slab http://www.safecrete.com/aac/building/buildingwithsafecrete_new. I don't know if you can follow this but I pasted it in. I'm in central North Carolina so not alot of cold weather.

Why not just use ICF ?

ACC is higher in costs than other ordinary concrete plus it is not as strong as conventional concrete. It will also be hard to find contractors who are familiar with autoclaved aerated concrete.

I don't think that ACC is even recognized by the IRC so getting it past the building department and your mortgage company might prove to be difficult.

Posted By UREdogLady on 24 Aug 2015 12:46 AM
Hi, it's me UREdogLady. If you were following Cheap and efficent you know my inexperience.Since Jelly advised a new tread I decided to try it. Alot of site considerations, insects and moisture foremost then theres unpaved roads and rear elevation, this is what I have been considering AAC blocks w / CMU base on slab http://www.safecrete.com/aac/building/buildingwithsafecrete_new. I don't know if you can follow this but I pasted it in. I'm in central North Carolina so not alot of cold weather.

The link you wanted to post is here:

http://www.safecrete.com/aac/buildi...te_new.cfm

I chose AAC over ICF because of the first rule of DIY: You will make mistakes so best that they be small ones. Here is an AAC builder in NC: http://www.sungardenhouses.com/ And the closest AAC manufacturer: http://www.aerconaac.com/ You will find both to very helpful.

Lbear is blowing smoke. building inspectors will take any plan that has an engineer's stamp on it -- extra expense true enough but also required for ICF. Lbear knows this so now you know Lbear. This was a while ago but the materials in my AAC house cost less per square foot than ICF forms alone, before concrete and pumper trucks. You can trowel stucco and plaster directly on the block. Or leave it bare. ICF must be covered, typically by drywall.

You will hear that AAC is insufficiently insulative, so I will merely introduce a rare concept on GBT. It's good enough.

Posted By Lbear on 24 Aug 2015 02:43 AM
Why not just use ICF ?

Lbear, if I recall budget is an issue, that's why she's not considering ICF.

UREdogLady, could you give us some more details? How big of a house are you considering? Will there be a second floor? Are hurricanes, earthquakes, floods, or tornadoes likely in your area? Will you be doing all the work yourself? What is the motivation for your green-building interest?

AAC blocks are very light and easy to lift and cut. Roof panels would be a different story (but you can use a different material for the roof). If Safecrete isn't that far from your site then shipping may not have to be too cost prohibitive. The price per block is what is still unknown. At this point I think it's good to keep an open mind to various construction methods.

Back in 2009, 8 inch block cost about $2.40/sf delivered to PA from FL if memory serves. Stucco cost more than the wall. Distributors like Safecrete generally can't do better than the manufacturer. They pay the same trucking costs and pass it along. Back then there were two plants in the SE. I think today it's just Aercon.

AAC would fall under "mass wall" category per the IRC, and would have to have the steady-state R minimums (not a dynamic load
equivalent R" value) for mass walls in your climate zone per chapter 11:

publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_11_sec002.htm

The mortar lines are thermally bridging, so you may have to beat those numbers by ~15-20% to get true code-min performance out of it.

If you're in US climate zone 1 or 2 you can use the equivalent-R numbers estimated by the Florida Solar Energy Center for an Orlando FL climate, cited by Aercon in Table 1 in this document:

http://www.aerconaac.com/technical-manual/Thermal%20Efficiency.pdf

So while an 8" Aercon AAC wall beats a steel sided wood studded 2x4 building with low density R11s, it doesn't quite beat the thermal performance of crummy R19s in a 2x6 wood framing even in a cooling dominated climate like Florida. That said, it would still make current code-min performance in zones 4A & 4B, but would not in zone 4C, nor or in zones 5 & higher. (It would roughly meet code min performance for zone 5 under IRC 2006, but not IRC 2009 or later. )

I just read your other thread, URElady, and I'm not going tell you what you can't do because your determination is the only essential ingredient. Just a caution. Lightweight concrete takes on a different meaning as the day wears on. My 1600 sf AAC house was delivered on two flat bed semis: 45 tons in total not counting the conventional mortar poured into reinforcing columns every four feet and bond beams at the top of the wall. The blocks weight 31 pounds each. Truing them in three dimensions is not as easy as it seems. You'll spend your days bent at the waist sighting down the wall, vertical being the dimension easiest to mess up. Keep it small. Keep it simple. Avoid deadlines. My county charges $10 to roll over a building permit for another two years. A mortgage company won't have that kind of patience. Nor will insurance companies until the structure is completed.

Stucco and plaster are art forms. Try it but be ready to admit defeat (as I did.) If you have the knack, plaster works out to about 25 cents a foot for materials IIRC and stucco for less than a dollar. Siding over AAC is simple. A five inch wood screw in AAC holds 70 pounds. Normal saws and power tools. You'll need a box store cement mixer, an industrial hand cart and some scaffolding. Add foam insulation boards between the furring strips under the siding and you will have an efficient house. Reclaimed foam board is easy to find.

Shotgun houses minimize interior walls. Google modern shotgun house to see some surprisingly attractive plans.

THANKS TO ALL FOR YOUR IMPUT :I have contacted AerconAAC and requested a price list for blocks,I guess thats the way I'm leaning especally if I can leave them unfinished at first then go back later w/ whatever trim, sealer, paint, and solar panels. The house itself I haven't nailed down yet, though I've looked at floor plans for hours on end. Just a small 24'x 36' one story w/loft- one slope roof - over open front for porch. Mostly open with central plumbing.Rear elevation if I don't get completely level, granite or river rock might be an issue.There is a mountain behind me (Well in the south they call it a mountain) and alot of trees to clear.I'm in zone 3 it looks like.I have a well and septic tank a 12x48 singlewide to live in until complete.If it was on a slab I'd probably move it first but,it isn't. zoning allows me some time before it goes.I think that covers it except Why build Green? because its right.

Why build green? If by "green" you mean "high performance", because it is much more comfortable, far less expensive to operate, more resilient, less problems down the road.

ps off the river above flood plane no other natural catastopes expected.

I have been thinking about it and AAC may be your best option if you have plenty of time. The reason is because it unfolds one block at a time. If you set 10 the first day, which wasn't far off my initial production, those blocks will be just fine in two months or six months or however long it takes you.
You'll need help four times. Sungarden can point you to a NC engineer who knows AAC. You'll find that people in the AAC business, which is struggling on the residential side, take a missionary approach. They want you to succeed and are happy to help. As I said earlier, you'll need an engineer's stamp. Mine drew up the blueprints as well. You will want to minimize cutting blocks, which means the walls, windows and doors are placed at 4 foot intervals. Also you want doors and windows terminating on the same course of blocks. More about that later.

Next you need a mason to set the all-important first course, which is bedded in regular mortar to compensate for the inevitable discrepancies in the slab. Because AAC is milled to a sixteenth inch tolerance on the mating services, it is almost stackable -- as long as the first course is close to perfect. You should be able to find an experienced guy willing to moonlight it on a saturday. $200 very well spent.

lintels are structural pieces 12 inches high and 16 inches wider than door and window openings. You'll need help setting them, which why you want everything at the same height.

Finally, it is heavy work pouring mortar into the support columns tieing the walls to the slab and into the trough of concrete at the top that ties the walls together -- the bond beam -- and it happens eight feet in the air. Another day you need help. The lintels and pour need only strong arms.

That leaves the roof and interior walls. Aercon will tell you that its panels must be installed perfectly flat. Not sure where you saw them used for anything but a flat roof. I used 40 of them, 2 x 7 feet, and about 350 pounds each, for a deck over my garage. Three of us cranked them up in a day with a Genie hand lift. Gotta say there was no race for the crank from 2 pm on. A flat roof done right costs more than a conventional pitched and shingled roof, which is what I would do.

The good news: in most jurisdictions you can get occupancy in bare AAC walls and a working kitchen and bathroom. Of course living in and working on a house is no fun, particularly if the builder and cleaner are the same person. It can be done.

toddm very, very helpful, I'll have no time restrictions, so I can DYI with help from nephew, neighbors and friends whenever they show up. One thing though. On the safecrete site, it has rebarb run through the support columns instead of concrete, looks easier if I can do that instead of pour.When I contacted their phone # I got Taylor Trading who is the middleman for Hubel, but he said that a prior customer in Raliegh NC had leftover blocks and that he'd email me the contact info. I dont know about mix and match on brands and I doubt leftovers would be enough, but I guess i'll find out. maybe I can use them for a fireplace or chimney, they're supposed to be fireproof. Any thoughts?

You put rebar in the columns, rebar in the slab sticking out 2 feet, rebar in the bond beam and then fill everything with concrete. (Actually it is easier to place the bond beam rebar after you fill the columns and the bottom third of the beams.)

Mix and match shouldn't be a problem, While the tops and bottoms of the block are milled for a close fit, if you get enough block for a complete course, minor differences won't matter. You should guesstimate how many blocks in a course so you know how much is usable. I was told to protect the blocks from rain during construction. Less a problem for the blocks than for contractors applying finishes. An autoclave is a steam oven, and the blocks dry for up to a year after they come out. Covering them quickly raises issues for paint, wood, wallboard and so on. I had zero problems because of my construction pace. Slooow.

Hebel closed its plant in Adel, Ga. It has production now in Mexico. Dunno if it's open again in Ga. or not. Worth a call.
www.hebel-usa.com/

There is a difference between won't ignite and repeated exposure to 2000 degrees. You'll have ask about that one. I'm building an outdoor oven with my leftovers, (One day.) But I think I'd line it with fire brick or the special clay for ovens.

good idea-I considered fire brick lining for fireplace, but I have a nice cast iron woodstove I use when the power goes out (most winters for days at a time) for heating and cooking. So an open fireplace would be a luxury just to watch the fire. If I used my stove and lined the chimney w/ stove pipe it might be feasible.

Posted By UREdogLady on 26 Aug 2015 01:42 PM
good idea-I considered fire brick lining for fireplace, but I have a nice cast iron woodstove I use when the power goes out (most winters for days at a time) for heating and cooking. So an open fireplace would be a luxury just to watch the fire. If I used my stove and lined the chimney w/ stove pipe it might be feasible.

An open hearth fireplace is more than a luxury just to watch a fire, it's  24/365 air & heat leak and an enormous PM2.5 emissions source- a real energy efficiency and air pollution disaster that has no place in an efficient home.  

An EPS rated cast-iron or soapstone wood stove with a nice viewing window gives most of the aesthetic ambience of an open hearth fire, with more an order of magnitude less PM2.5 emissions, and more than two orders of magnitude less air infiltration/heat-loss.  If you want to roast marshmallows by an open fire, do it outside.

Posted By Dana1 on 26 Aug 2015 02:09 PM

Posted By UREdogLady on 26 Aug 2015 01:42 PM
good idea-I considered fire brick lining for fireplace, but I have a nice cast iron woodstove I use when the power goes out (most winters for days at a time) for heating and cooking. So an open fireplace would be a luxury just to watch the fire. If I used my stove and lined the chimney w/ stove pipe it might be feasible.

An open hearth fireplace is more than a luxury just to watch a fire, it's  24/365 air & heat leak and an enormous PM2.5 emissions source- a real energy efficiency and air pollution disaster that has no place in an efficient home.  

An EPS rated cast-iron or soapstone wood stove with a nice viewing window gives most of the aesthetic ambience of an open hearth fire, with more an order of magnitude less PM2.5 emissions, and more than two orders of magnitude less air infiltration/heat-loss.  If you want to roast marshmallows by an open fire, do it outside.

Dana is 100% correct on this. Open fireplaces are an abomination to a home and the environment.

They are actually illegal to install in some counties due to the pollution they create. Maricopa County in Arizona is one such county that forbids open fireplaces in new homes.

The EPA did a study in Alaska and found areas around Anchorage were so polluted during winter that the air quality rivaled that of industrial China. The cause of the poor air quality was due to wood burning fireplaces in peoples homes.

Well, excuse me !!!

UREdogLady, I think with your simple 24 x 36 AAC rectangle that a steel SIP roof would be a great option for you. They are very light so no crane would be needed. If it's just one slope then there wouldn't even need to be any cuts made and you could tape the seams and use it as a finished roof. Depending on the SIP thickness and the span there may not need to be any secondary support either. A roof like that could be finished in a day.

A smart interior design can save money and sweat. Read Sarah Susanka's Not so Big House for tips on maximum use and minimum walls. You might want to heft a sheet of wallboard down at the box store for extra motivation.