ICF's (insulated concrete forms)

Discussion in 'Homesteading Questions' started by Randy Dandy, Nov 16, 2004.

  1. Randy Dandy

    Randy Dandy Well-Known Member

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    Is there anyone that has built a house from this system or know someone else that has ? We have been seriously considering this type of system. We would mostly like to know how long the house has been built and if they are satisfied with it. Thanks, Randy
     
  2. ibcnya

    ibcnya Well-Known Member

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    Randy I built my own house 2 yrs ago using the ARXX ICF forms. I used the forms because even a novice builder can put these up. Just remember plumb and square. I built a 30x50 1500 sq ft berm home using this system and I live in southern Iowa. It faces south and 40 ft of the 50 ft south facing wall is a 2x8 wall with the 10 ft left making 5 ft wing walls on each end for stability. I used plenty of windows bought at left over construction auctions on the south side and bought lots of R-10 pink board insulation for 20 cents on the dollar when Wabash trailers went out of business and put that under the whole 4" concrete floor. I also put in pex tubing for in floor heating but haven't hooked it up yet. Wanna know why? Because this house is so warm that I only stoke the wood burner once a day. I can keep it 85 degrees in here with 2 stokes a day and the sun shining outside and -10 below. If you have any questions feel free to ask.
     

  3. moonwolf

    moonwolf Well-Known Member

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    The small store building here was made by the Blue Max system. The walls are concrete poured into interlocking styrofoam forms. What I liked about it is that I needed a building with 11' inside walls which the system easily accomodates because it's not a framed lumber building. The strength of the building is also a big plus and being very well weather sealed. The building went up fast, too.
    Once the concrete flooring was down, the forms took a day to put up by a construction crew of 4 and the next day was poured and done to the roof truss stage. This was a building about 36 x 40. The styrofoam forms are spaced with x braces every 10 inches I believe and from there the siding and drywall was screwed in.
    This system would be initially seem expensive for house building, but savings come from time in construction with conventional framing. Also, what you have is a very quiet building and well insulated, sealed with harldy any caulking involved anywhere except around installing windows. A good structure to build probably in high wind or storm areas also, being structurally very strong. Also consider no nailing involved using lumber or with using other stud type of construction.
     
  4. gobug

    gobug Well-Known Member Supporter

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    I helped a friend that built one. I only helped a few days. He had a crew assemble and pour the ICF's. I don't recall the mfg, but they were 2 piece forms held together with special fasteners. The assembly of the 2 pieces created the cavity for the concrete. In CO, slab basements are no longer to code due to radon and bentonite. So his basement has a raised floor, with a shallow crawlspace beneath it. The house is totally silent inside.

    A few concerns from a different perspective: foam has some liabilities. 1)Termites are not deterred at all from going through the foam. While the primary support structure will be foam and concrete, there are many wooden materials, like rafters and interior walls. 2) Carpenter ants absolutely love to nest in it. While they do not eat the foam, their nests are large enough to compromise the integrity of the foam/cement/rebar support. 3) Regular bead board foam is not designed to be subterranean. There are issues with water, fungus and mold. Most codes have stipulations about what kind of foam can be buried. The mfgs should be fully aware of this and have specific directions for use below grade. The bug problems have been successfully addressed by some mfg's with the addition of a minute amount of boric acid in the foam block.

    I mention these concerns only for your awareness, not to dissuade you. I think homes built with this process are great.
     
  5. Hurricane Kurt

    Hurricane Kurt Well-Known Member

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    ibcnya... I sure like the sound of your house. Do you have any pics that you could post?

    I plan on building our next home, this summer hopefully, and am trying to settle on a good passive solar design around 1500sq. ft. What I am pretty sure of so far is that I'm going with dry stacked blocks and stucco and a lot of window area on the southern wall. I was also leaning towards a radiant heat system but am second guessing it after seeing comments like yours about its just not needed.

    A few questions about your house; Do you have a growing area inside? What size windows did you use and at what angle, if any, are they at? What type of roof do you have? How did you run your wires inside? Anything you would do differently now looking back?

    Hope there aren't to many questions... thanks alot.

    Kurt
     
  6. Ed K

    Ed K Well-Known Member

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    I built an ARXX house starting in April 2003 I moved in August 2004. (I self contracted so it took pretty long) I am very satisfied so far. Its quiet and tight. I have radiant heat but currently I'm only heating one level yet. (haven't got thermostats for the rest yet.) Heating one level works pretty well for the whole house. The gas company hasn't read my meter yet and it's not real cold yet so I can't say if my energy savings are all they're touted to be but I'm happy so far

    Best wishes

    Ed
     
  7. ibcnya

    ibcnya Well-Known Member

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    Moonwolf, Bluemax is now ARXX. For Hurricane Kurt, I also toyed with the idea of drystacking blocks and doing the stucco thing. I still would have had to insulate from the inside to prevent condensation. I remember as a kid how our block wall basement would sweat and how mold would grow. So I decided to use ICF's not only for that reason but also because I was pouring it myself and the forms are built right in. I went to a local distributor and they hooked me up with a 1 day contractor's class that I paid a hundred some bucks for and received all the books and instruction that a contractor would get. I was sold on the system from day one because I could do it myself and I wanted to build a very very warm house because I hate cold. (I lived in the tropics 10 of my 20 yrs in the Corps)
    After the footing was poured and set, I stacked the forms and put up the braces in one very long hot day by myself. The next day I had 2 brothers help me with the pour which also a very long hot day. We had no blowouts which could be catastrophic. But because of the instruction I had received in the class, I had none. I think if I was to just buy and pour I would have had some problems. The roof was trussed on 24 in. centers with a 6/12 pitch. As for siding and drywall the forms have a tough plastic webbing that goes thru the form and both sides have a 1 in. strip every 8 in. that you attach drywall or siding to. Wires are run thru the wall by using a electric chainsaw to cut a groove in the 21/2 in. of styrofoam on the inside. The biggest pipe you can run in the wall is 2". Electric boxes are either screwed to the plastic webbing or tap-con to the concrete.
    I have some pics somewhere and will try to post.

    Try http://www.arxx.net/
     
  8. Randy Dandy

    Randy Dandy Well-Known Member

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    Thank you all very much. The feedback that we are getting from this system is really great. We finally found a contractor thats building a house from these forms called "Eco Block". Its not far from where we live and will be going to see the house the first thing in the morning. However we do seem to only hear about how easy they are to heat. I was wondering if they are as equally easy to cool. One of our thoughts was to build a so called "basement house". Having 3 sides mostly covered with dirt and one side exposed. We figure this would help with the heating/cooling as well but could a person get buy cooling by another method other than a heat pump ? If so then would there be enough air circulation ? Thanks, Randy
     
  9. Hurricane Kurt

    Hurricane Kurt Well-Known Member

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    ibcnya thats interesting about the sweating problem in your basement, I've never seen than in a concrete house or basement around here, maybe it had something to do with that climate or the construction method that was used or the lot itself.

    Randy its just as important to me to build a house that stays cool in the summer. I'm going to build in the Roanoke Va area and although its not the deep south it does get hot and humid in the summer. I have a relative that has a vacation home near Roanoke that I have stayed in many times, its an old concrete block house with a very open convetional design, 2 story and about 1500 sq ft. I am always impressed with how comfortable the house is in summer or winter. A small wall mount gas heater heats the entire house and one window a/c unit cools it upstairs, the downstairs never heats up if you keep the shades down on the sun and keep the windows closed during the day then open them at night letting cool air in.

    One of the reasons I'm going to use concrete blocks is because of that house's comfort level without a good design. The concrete alone makes it easy to heat and cool, I figure with a good design and proper placement it would be far superior.

    Another HUGE reason is cost. Its alot cheaper to build with blocks than the ICF's which are comparable to conventional stick built houses in price as best I can tell. The last thing I want is another mortgage and I don't have the cabbage to build a $150k home without one. It looks like I can build a nice block home for $40k or so, thats doable for me. I'm not dissing the ICF system at all, It just doesn't fit into my budget.

    Here is a website with lots of good info on thermal mass and passive solar theory, I don't agree with everything there but I have got lots of good ideas from it. http://www.thenaturalhome.com

    Kurt
     
  10. Randy Dandy

    Randy Dandy Well-Known Member

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    Thanks alot. Thats a really cool site with lots of info. Good luck with your future house building. We just got back home from visiting a house site built with ICF's. Like the contractor said, you should still have a small heat pump to help circulate and filter the air. I tend to agree with that thought. The only other way that I could think of to keep the air circulated without a heat pump is to have ceiling fans. The only bad thing that I can think of about building with block without any insulation is that I've read several web sites that state if a house is built on a basement for example then a very large portion of energy is lost through the walls of the basement if not properly insulated. But thats just what I've read so far. Thanks, Randy
     
  11. DreamingBig

    DreamingBig Well-Known Member

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    I've been interested in this system also but didn't realize it's so expensive. :( So I'll look into concrete blocks. One concern I've had about the foam is fire. Burning polystyrene is extremely toxic; the smoke can kill you in seconds. I noticed the website claimed a three times longer escape time from fire. Does anyone know anything about this?

    Thanks for the link to the Natural Home. I would like to have a waterless toilet and it's good to know the SunMar is so highly thought of. The Clivus, the only one I've experienced, has been my first choice--100% odorless. But it's expensive and requires a basement, and you can only have two toilets if they're right next to or right above each other, which doesn't fit my preferred split floor plan. :)
     
  12. Randy Dandy

    Randy Dandy Well-Known Member

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    I have seen the same claim that you have about a longer fire escape time. I dont think that the insulation material over the concrete should be of too much concern due to the fact that it is covered by drywall and the isulation should not burn like wood can catch fire behind drywall. I will do some more research on insulating block houses like you are considering and try to post it. I'm 99.9% sure that its highly recomended. As far as cost its not that much higher if any from the systems I've compared.
     
  13. Randy Dandy

    Randy Dandy Well-Known Member

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    Here is one site that I found fast. http://www.buildingscience.com/resources/foundations/basement_insulation_systems.pdf If you dont build a basement and build above ground then you stand a very high chance of a moisture/mold problem at the base of your walls if you dont properly seal AND insulate. Even in todays crawl spaces they have done several studies and found that the crawl space foundation walls should be insulated to help keep down the fluctuation of hot/cold thus no sweating and no mold. I hope this helps. Thanks, Randy
     
  14. Hurricane Kurt

    Hurricane Kurt Well-Known Member

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    I wouldn't buy an exspensive heat pump for those reasons. I mean think about it, the only air thats going to get filtered is whats coming out of duct work, not air thats already in the house. I do agree that they will move some air around, I have one in my home now and thats about all its good for :) This does not seem to be a logical solution to air movement or filtration.

    It kinda defeats the purpose of building a house with high thermal mass in mind over a basement. I'm going to take advantage of the largest amount of mass I can, the earth, and build directly on it, no crawl spaces etc.

    Alot of the moisture problems that are related to mold or mildew in block basements don't transfer into block homes imo. Basements don't usually get much natural light nor do they get heated and cooled like the living spaces or were they designed to for that matter.

    I have a room in my current house that gets mold spores on two of the walls now. It has to be cleaned on a regular basis so it doesnt grow. Its caused by the walls getting condensation on them. This is basically caused by a temp. fluctuation, not enough thermal mass to keep a constant temp. perhaps. The house is brick and highly insulated with drywall inside, not block. I guess my point is, if there is one, Concrete block isn't any more vulnerable to these types of problems than any other building material or method.

    Kurt
     
  15. gobug

    gobug Well-Known Member Supporter

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    Here's a website by a guy in Texas who is building his house of cinder blocks. Each week he has posted a set of photos and explanations of what he is doing. He has been working on this for more than 18 months now.

    http://www.texasmusicforge.com/gimmeshelter.html

    Cinder block may have mass, but the R value is poor. Additionally, cinder block or concrete are like a sponge when it comes to moisture.

    A common mistake made in new homes with basements in how the vapor barrier and insulation are installed. Above ground, the vapor barrier goes as close to the living space as possible. Underground is the opposite. When the insulation and vapor barrier are installed inside in the basement, the concrete walls cannot lose their moisture, and a perfect environment for molds and mildew is created.

    Subterranean concrete walls, including cinderblock, must have proper underground style insulation and a vapor barrier outside against the soil.
     
  16. Randy Dandy

    Randy Dandy Well-Known Member

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    Thats what I've been reading also gobug. But Kurt has a good point about the air circulation that I didnt realize. I have been reading some sites that talk about how heat pumps circulate the inside air only and that there are systems that heat and cool that also infiltrate fresh outside air in recommended proportions. I would imagine that these systems are higher in cost. I agree with everything you stated gobug. It matches all the conclusions I've come to from all the info I've read. I would also like to do what Kurt said about taking advantage of the earths resourse. I still wonder if we build a one level home on a slab useing the ICF system and the house is covered by dirt 3/4 of the way up, but open on one end, and we had a radiant heat floor system in the slab for winter, then would the dirt around the house keep it cool enough in the summer for us not to buy any kind of air conditioning system. Would ceiling fans be enough ? Please help :waa:
     
  17. BeckyW

    BeckyW Well-Known Member

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    My familiarity is with 12 inch thick adobe walls. I'll bet they come in at somewhere around R40-R50. In Bakersfield CA which frequently sees summer temperatures of 105-106, that adobe structure didn't exceed 80-85 degrees without any air conditioner. (Key was closing up the house and drawing blinds by 8:30am). Ceiling fans in every room. Now, humidity is VERY different in Tennessee however I'd bet ceiling fans could do just fine. And if they don't quite, all you would need is one window AC, maybe two if you're over 2000 sf, for the worst days/nights of the summer. I'll bet, though, closing up the house in the morning before 9:00 and dropping the mini-blinds would probably do the trick.

    Oh, your flooring also makes a difference. Bare Mexican paver tiles in the CA house in spring/summer/fall -- large area rugs for the winter.

    I'd suggest you contact the manufacturer. I'm sure they have info on that. Have your heat calcs on the house handy.
    BW
     
  18. Hurricane Kurt

    Hurricane Kurt Well-Known Member

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    Ya know this is the same thing I wonder about and can't find a good answer to. My plan is to just see what it ends up feeling like in the house on a hot day and go from there because I am not going to install any sort of hvac system in the house.

    My heating will be taken care of by a free standing wood stove. I plan on using a good de-humidifier, ceiling fans and strategicaly placed windows to draw a breeze. If it gets uncomfortable in the heat of summer I'm going to get a pair of self contained air conditioners on wheels. These cost between $350-$500 a peice for 7500btu units. I'm figuring $2500 for these items in my budget which is still alot less than a mediocre heat pump system with duct work, registers etc. not to the mention cheaper electric bills. We'll see.

    Kurt
     
  19. ibcnya

    ibcnya Well-Known Member

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    I use two 5 or 6 thousand bTU window A.C. and that's it for cooling. Also keep the south curtains closed in the summer.