# Anyone have experience with those Styrofoam building blocks that you stack up like legos and fill wi



## Seasoned Oak (Feb 11, 2010)

I hear they are an R40  after being filled with concrete ,and a great heat sink to boot.not to mention termite proof with the concrete anyway.


----------



## SE Iowa (Feb 11, 2010)

Yes, I built a 3 storey all ICF, all brick home that was ~4600 internal sf.   Also poured a VERY difficult foundation for my fathers house this summer using the same ICF's.  Up until I built my house I had never constructed anything, but I enjoy that kind of challenge.


----------



## Highbeam (Feb 11, 2010)

I helped with a house that the basement to the floor joists was ICF construction. The other cool thing is that the ICFs hold the rebar in place. The steel scaffoling/form support structure was extensive and pretty unique to ICF construction. The window bucks were very deep. 

I don't know about R40 though since the foam is only a couple of inches thick on each side and its an expanded polystyrene foam with an R-value of only like 5 per inch. I don't know how much better it actually performs than a similar RC wall with foam applied to the inside.


----------



## lowroadacres (Feb 11, 2010)

When we bought a used cedar log house to move to our acreage we weighed everything out and made the choice to go with insulated concrete forms or ICF for short.

The main reasons we went for ICF were ease of handling, increased insulation values and resale value.

Due to the fact that we did not have to rent forms or hire someone to form up the basement before the pour we did the ICF basement for less than we would have paid a contractor to construct a traditional basement.  This was magnified by the fact that we did not have to strap and insulate afterwards but rather we were able to hang the drywall with relative ease.  I say relative because we did one tiny thing wrong.... Somewhere along the line of stacking the blocks the instructions that I had been given from our contractor friend did not make it from me to my buddies and the "X"s" on the blocks did not line up after the first three courses of blocks.  This added several hours to the drywall job as we had to map each set of anchors and measure and pencil mark each drywall sheet to be able to hang them up properly.   

Needless to say the fellow doing the mudding, taping and sanding for me got a real kick out of my handiwork.

I would highly recommend the product and if we ever build again (I hope not as we still aren't completed this house  ) we will be using the product again.


----------



## SE Iowa (Feb 11, 2010)

I do not know what the rated efficiency is on my blocks. All I can give is antedotal results. We have all radiant floor heat in gypcrete on the floors. We use a Weil-McClane ultra condensing boiler on NG. We heat our main level and bathrooms to 70F and the bedrooms to 69F. Our largest gas bill was for $185 for one very cold month (note that we have an instantaneous hot water heater and cook on NG too). We spend far less than $1000 per year heating our home in a reasonably cold climate (this am it was -8F). We do notice that the heat mass in the walls and floors coast up and down which is where I assume we gain alot of efficiency. For the most part, the efficiency of the house has held me back from buying a wood boiler. It just wouldn't pay.

Of the many things I now know about the pros and cons of ICF construction and experience from living in one, I would say that you should defiantly make sure that you buy the absolute top of the line windows when building an ICF home. They are the weak link in the system.


----------



## jklingel (Mar 14, 2010)

R40 is somebody's bad dream. Concrete has an R of about 0.5/inch. You can not get more than R20 out of the foam, and that is only where you have not scarfed out the inner insulation to run a wire for an electrical box. Above grade, if you have a moderate climate and can get them heated w/ the sun, then great; free heat is always nice. ICFs are a very good product, when they are appropriate. At $25/block, plus concrete and rebar, they are not cheap. You can frame a wall w/ a real R40 for a whole lot less money than ICFs. If you want a wall to be straight and plumb when you are done, then you need a gackle of bracing before the pour. That needs to be thought of before you lay in your PEX in the slab. The bracing needs to be anchored to the floor. And, WATCH THE CAT WHO RUNS THE VIBRATOR! We had two blow-outs on my son's walls, because the "pro" brought the wrong vibrator. We only poured 6' high, and it is sickening to see all your mud suddenly get sucked out of the wall. Fortunately, we had 3 guys w/ screw guns and plenty of plywood, so the losses were minor. ICFs are a lot of work, but you have a very solid wall when done. Thermally efficient? In some locations. Below grade? I think they are the way to go there, if you have to also insulate on the outside of a cinder block wall, as a comparison. My prices were the same for a cinder block foundation wall (w/ XPS) and ICF walls. I will choose the ICFs over laying 2000 cinder blocks. I would suggest, too, that you insert wooden 1x4 L's, vertically, in the corners, because they may be handy for locking down sheet rock. And, if above grade, have fun hanging pictures, etc, on the walls, unless you plan ahead somehow. That's my take on them. I don't see them used above grade in many super-insulated houses that are shooting for less than 10 btu/sf heat losses in cold climates.


----------



## jklingel (Mar 14, 2010)

PS: Termites love styrofoam. I'd treat them w/ something, if possible, if I had termites around.


----------



## SE Iowa (Mar 14, 2010)

jkilingel,

Sorry about your experience.  I have had just the opposite experience.  Mine were only $16/block, we had minimal bracing, no blow-outs and as far as EFFECTIVE R values, I bet we are not too far off of 40.  My icf walls go up 3 stories and only vary by 1/2 inch at the most (i.e. strainght, level and true).  On the average winter day, we go thru 500,000 btu's which includes hot water and cooking gas.  Taking a small amount out for those 2 things and dividing by 4600 sf we probably are near 4 to 5 btu's/hr INPUT for our house.  

  The real advantages include the uninterupted insulation envelope, heat mass "coasting" and lack of convectional air movement/loss.  We also enjoy greatly reduced sound transmission.  

  It is not all a win-win situation.  There are some drawbacks as with anything, but I sure am happy that I went with all ICF's.


----------



## Badfish740 (Mar 14, 2010)

lowroadacres said:
			
		

> When we bought a used cedar log house to move to our acreage we weighed everything out and made the choice to go with insulated concrete forms or ICF for short.
> 
> The main reasons we went for ICF were ease of handling, increased insulation values and resale value.
> 
> ...



We want to build a log home new and I'd like to put it on an ICF basement simply so that I could do it myself and just hire out the excavation.  This thread will be an interesting one to follow.


----------



## Later (Mar 14, 2010)

Have a friend that built a second home with these along the Canadian border in Northern NY. He closed up the home in the fall - no heat, no electric, his lowest indoor temp for the winter was 37 degrees. I'd use them in a minute!


----------



## Chris S (Mar 14, 2010)

I built 2 large homes with ICFS- from footing to roof, as well as some smaller projects.  
As for R-40, as posted above this is not true,  the R value is the combined R values of the material, nothing more.  The claim that your wall will perform like R-40 is true however largely due to the elimination of drafts- especially at electrical boxes, and the typical foundtion to framing - sill plate area.
I did 2 jobs with Owens Corning, then switched to ARXX.  There are several others, but the blocks like ARXX are far superior to anything else I have seen on the market.  
Part of the problem with these products though is that people view them as a do it yourself project.  Whil they are easy to handle, and go up like leggo blocks,  if you have a lot of corners, irregular windows, or other challenges  ( We poured some 12' high walls) be prepared.  I watched one job that took almost a year because the homeowner thought he could do it all with his wife.  
Also when you pour have lots of help.  My last pour was 80 yds of concrete, which is substantial, and I had 8 experienced men on site that day, and everybody worked throughout the whole pour.  Part of the reason being the pump costs by the hour, so we wanted to minimize that.
For a handy person, a building without too many corners and details is definitely do-able, but watch the videos, pay attention, and follow their instructions to avoid blow outs & worse.  For the OP if you want more info & pics, pm me.
Chris


----------



## jklingel (Mar 14, 2010)

SE Iowa said:
			
		

> jkilingel,
> 
> ... EFFECTIVE R values, I bet we are not too far off of 40. On the average winter day, we go thru 500,000 btu's which includes hot water and cooking gas.  Taking a small amount out for those 2 things and dividing by 4600 sf we probably are near 4 to 5 btu's/hr INPUT for our house.
> 
> The real advantages include the uninterupted insulation envelope, heat mass "coasting" and lack of convectional air movement/loss.  We also enjoy greatly reduced sound transmission.


 •• Glad the ICFs worked out for you. When I've run the numbers, an ICF wall costs a fortune. You can build a stick house tighter than necessary (HRV REQUIRED), with an uninterrupted insulation layer, far cheaper, and w/ a far better R than an ICF. Passive solar heat gain can also be easily achieved w/ a stick house. That is one of the functions of good windows. In fact it is not uncommon to have too much heat gain if precautions like trees and overhangs for shade are not thought of.  However, if you like ICFs, and like the quite (which I suspect is more than w/ a 14" cellulose wall), then git 'er done. You'll have a wall that will outlast a few generations, too. I just can't see putting that much money into a house in my climate. Moderate climates? Perhaps so, but the expense is unavoidable, as far as I can see. Once you've been in your place a couple of years, post us with the actual fuel consumption and your heating degree days. It would be informative to see the numbers. In the meantime, ROCK OUT WITH THE BAND! The neighbors won't hear you.


----------



## leaddog (Mar 15, 2010)

Make sure you don't want to do any remodeling or changing as it's alot harder to do once the concrete is poured. 
leaddog


----------



## SE Iowa (Mar 15, 2010)

Jklingel,  We've been in our home for almost 3 years now.  Total utilites for the last 2 complete years averaged $1100 for electricity and $1068 for NG.  That's about $180 per month on AVERAGE for all utilities including hot water, etc for 4600 square feet, although we don't use the basement very much.  I'm very happy as our temp swings from lows of -20F with prairie-style wind in the winter to 95F and 85% relative humidity in the summer here.  Probably not like fairbanks with the ocean tempering the temps.


----------



## begreen (Mar 15, 2010)

Also being discussed in the DIY forum. Many years ago, a contractor friend locally raised his house up a story and put it on an ICF basement wall. First in Seattle. It has done well and was a fun project for him. The basement is noticeably snug and warm. The R value of 40 or 50 is a myth. But so is the standard R15 stud wall due to bridging. For good info try this site: http://www.icfhome.com/DYKpages/dykTRUTHmyth7.htm

DIY thread:
https://www.hearth.com/econtent/index.php/forums/viewthread/53926/


----------



## mbcijim (Mar 16, 2010)

I posted on here before about this subject.  Search for ICF's and my user name.  I used Reward Wall, additionally I own at least 100,000 sft of commercial 1 story buildings constructed out of it.

My first home was built ICF from foundation to attic.  Heated 3,200 +/- with 550-600 gallons of oil per year in Pennsylvania.  I lived in it 7 years no termites.  I can't see how termites can affect the home.  Even if they ate the styrofoam on the exterior, they can't penetrate the concrete or interior styrofoam.  Not a worry for me, or my commercial buildings.  Some are 10 years old in August and still no termites.  Reward advertises R-32; I know you can buy different thickness block, I imagine if someone is advertising R-40 it is probably a 12" wall, vastly unnecessary for residential construction.

Would I do it again?  
Pro's:  house was quiet, energy efficient, made great windowsills, peace of mind of living in a concrete house, definitely helped sell the place.  
Con's:  expensive, very inflexible after construction complete, takes longer to build than stick house

Second house was done using precast wall foundation.  It too was expensive.  Due to first house sale I really didn't have the time to wait for construction either & no builder.  

DIY?  I can't see how.  Special bracing needed is pretty custom to ICF.  Not sure how a DIY'er could find the bracing.


----------



## jklingel (Mar 16, 2010)

SE Iowa said:
			
		

> Probably not like fairbanks with the ocean tempering the temps.


 Your bills are not bad at all. Here is a link to an ICF discussion (plenty more there, too) on another site that I find very informative, too. I have not yet found the advisers there to have a particular ax to grind, except, naturally, doing things as 'green' as possible. http://www.greenbuildingadvisor.com/green-basics/insulated-concrete-forms#icfs have a relatively low r-value  Now, for the ocean tempering. In Iowa? If you meant in Frb, you've confused us w/ those folks down in Ang-kridge (Anchorage). We are in the interior; middle of nowhere, in a way. Anchorage has a much milder climate, but wetter. We have 14000 HDD, so some things that work well Outside are not as good for here. For comparison, the most HDD I can find for Iowa (only several cities listed in my old book) is 7800 for Mason City. Based on my fuel usage for 30 years, we range from using 4.75 btu/sf/hr (6 people in the house, and prior to some significant "fixes" I did) down to 3.8 btu/sf/hr with just two of us (and two mini dachshunds.... little heaters). I'll do things better on the new house, too; almost looking forward to building.... almost.


----------



## Hunderliggur (Mar 16, 2010)

I used ICF for the basement of my appx 4000SF Cedar Log house.  Basement is about 2500SF.  The ICF's worked very well with minimal bracing.  I would use a little more bracing next time but I am happy with the results.  Setting the forms was done easily after the first course was laid. Concrete was pumped.  The ICF's for my house filled a 53foot semi (the driver liked it - he got paid by the mail for a very light load).  I used a PVC "waffle" for the waterproofing on the outside.


----------



## jklingel (Mar 17, 2010)

Hunder: Sizable looking place there, and seems well finished. How many battalions are you going to house? j


----------



## ihookem (Mar 18, 2010)

I can see using them for a basement but not above the basement. I have 2x6 walls with 4 1/2" of foam. I also have brick that adds R2. This comes to an R 33 for a wall. I could easily went with 2x8 studs and went with 6 " foam and brick. This would be R 44 for walls.  At 0*f my heat load is about 30k btu's. I have 2" foam on the outside of the blocks under ground. I also have 1" - 1 1/2" foam inside the basement walls. I also have R 60 in the attic with 8" energy heels for my trusses. I don't think I can get cheaper R value any other way.


----------



## Hunderliggur (Mar 18, 2010)

For the most part I agree with ihookem about ICF below ground and stud and foam above.  ICF can be good for high wind load (hurricane) areas.  There is a 2 story ICF house in my area.  My options for the basement were poured concrete panels which would have required added insulation on the outside or the ICF's.  Since I did my own construction (except pouring the slab - I know better) the ICFs were in the end more cost effective for me and yielded a nice and square foundation.  The Department of Energy has a free program called RESCheck which allows you to evaluate different construction and insulation including traditional frame, solid log, and brick.  For my area, 6 inch cedar log walls give me better than the required building code energy efficieny in my area.  My metal roof is also energy star compliant which reduces summer heat load.

The house is 3BR, 2 1/2 bath plus a 2BR, 1 bath guest wing (mother in law apartment).  I learned on my last house that basements are cheap and you don't want to expand it later.  No problem getting my two 500 gallon storag tanks in to the basement ;-).


----------



## Como (Apr 7, 2010)

Sip's have their advanatges as well, it deends on what suits your particuar situation Stick framing has the inevitable issue of thermal bridging and may be a significant issue deending on climate.

I am more familiar with AAC, but they seem not to be widely available.

For ultimate R Value nothing can beat Sip's.


----------



## nojo (Apr 16, 2010)

mbcijim said:
			
		

> DIY?  I can't see how.  Special bracing needed is pretty custom to ICF.  Not sure how a DIY'er could find the bracing.



ICF Blocks use internal bracing for the most part. Creating any needed extra bracing would require less 'stuff' then bracing traditional forms.


----------



## Hunderliggur (Apr 17, 2010)

Having built a large ICF basement (53 foot semi trailer of blocks) I have some experience.  Bracing is important but not beyond traditional building techniques.  The ICFs themselves are pretty stable but you have to brace them true to hold the concrete.  You do not have to brace the weight of concrete like a plywood form, the blocks do that.  There are basic bracing techniques in most instructions for ICF.  You should brace both the inside and outside.  My longest straight wall was 40 feet and they all came out true.


----------

