ICF Walls

[mbcijim]

ICF = Insulated Concrete Forms. I built my 1st house out of this. They are two styrofoam panels - one inside the house and one outside. They pour concrete (4"-6") in the middle. The brand I used gave me an R-32 wall. The wall goes from the footer to the roof. The roof (cathedral) I put 3" of rubber roof blackboard insulation then sprayed it with 3" of spray foam. It is 2,050 sft plus a heated 1,200 sft basement.

The result is a very tight, well insulated house. At the time (2000) the cost to do build the ICF labor myself was the same as hiring a builder to stick frame the house.

I heat with oil and used 500-600 gallons per year (3,250 sft total) keeping the house in the low 70's. You guys will be happy the new owner is in the process of putting in a OWB, although I can't get him to read this board! My oil delivery guy asked me if I was getting oil from another guy because I was using so little oil. That was when I knew the ICF walls worked!

It's expensive, but something that should be considered for new home construction.

I used Reward Wall brand name, but there are many other kinds out there. For all I can tell, they are all basically the same.

 

[WILDSOURDOUGH]

I used ICFs for the foundation and SIPs for the Upstairs (Ranch)- Put Radiant in the full walkout basement slab with an OWB.
I will attest that they are the only way to go for new construction- though there will be less of that going on.
I heat the entire home with the radient in basement slab- I have no heating source on the 'main' floor level. It works beautifully- nice an warm.
Basement maybe gets a little too warm, but no complaints from the wife or 91 year old mother-in-law.

 

[dvellone]

Cost the same as hiring out the framing? Are you comparing it to just the stickframing because as you know the forms provide, all in one pour, framing, sheathing, insulation and vapor barrier. In that regard it would be substantially cheaper.

I'm gearing up to build my house and have been considering the forms or timberframing with lumber from my property so I would be greatly interested to know cost comparisons.

 

[mbcijim]

Keep in mind this was 2000.

The cost, stick framing, for material and labor was the same as the cost for ICF's, material only with all labor self performed. It took me about 3 monts to do all the labor myself.

 

[Highbeam]

Does that cost for ICFs only include the actual foam forms? Or do you include the rebar and concrete? I helped assemble an ICF basement and there was a good bit of cost in bar, mud, and scaffoling as well. Even the stick framed house needs a footing and stemwall. Then you have the pumper truck guy, etc. Finish work was different too with the plumbing and electrical outside of the normal wall.

 

[mbcijim]

If you're question was directed to me, by material I included concrete, rebar, ICF forms, pump guy, spray foam, and screws.

I had a friend lend me scaffold. You do need special scaffold, stuff almost exclusively for erection of ICF. I was fortunate to get that given to me. That's the hardest part about self performing this job.

 

[WILDSOURDOUGH]

If you are building- The Forms (ICF's) probably have not changed much in the last couple of years...
but the price of rebar, steel (lolly columes-I used 12-16" hemlock logs instead) and create- all of which used to be just an after thought... has gone up quite a bit. Just a cost to think about.

 

[SE Iowa]

I built a 2 story + basement colonial with 100% ICF outside walls. I was going to stick build my attached garage but at the time (2002) the cost difference was not very much and it was relatively easy so I built it with ICF's too. I put radiant floor heat in 100% including the slab in the garage (note the radiant in the house is embedded in 1.5in of gypcrete). Total above ground sf=2800. Garage is ~700sf but I do not heat it yet(temps never get that low in there). Basement is another 1750sf. Total conditioned space is ~4550sf!! I have an instantaneous boiler with 11 zones that runs on natural gas. My highest heating bill ever was $175 for one month. Typically we spend about $160/month during the 3 cold months and about $100-110/month another 3 months per year. This does include the service charges and the gas usage for our range top stove and our hot water heat (instantaneous though and ave only $5-10/month). It does get cold here but not usually longer than 2-3 months and usually only 2-4 weeks of that really artic sub-sero weather although it is very windy here on the the edge of the prairie (one reason why I build a ICF home).

If I had to do it all over again I would even at todays prices. I have something like 110 sq yds of concrete in the walls and #4 rebar vertically every 16" and horizontally every 32". My increase in cost would be ~$5000-6000 total for concrete and rebar. The forms would be somewhere around and extra $4000-6000. Total of b/w $9000-12000 extra. remember there are SOME extra cost with ICF anyway (extra long jamb extentions, electrical/plumbing slightly more etc). I guess I figure (in retrospect) that the savings from build with ICF's was equivalent costwise as putting in an OWB or gassifier BUT I do not have to do anything now such as cut wood etc. In addition it will never wear out or need maintanence or electricity etc. Utility rates will rise as well which will make the future even better.

 

[Chris S]

I've built a few jobs with ICF's including my own home (3600 s.f. ranch - over 250 yds of concrete) We used Owens Corning, but after some investigation, and training are starting a job shortly with ARXX. I was surprised to find almost a 50% price increase in 5 years. I guess the end product is green, but the manufacturing is oil dependant. One nice thing about the ARXX- the supplier will rent us their scaffold/ bracing system. My experience was 6000 s.f. of heated space on a hilltop on 1200 gallons of oil for 12 months including hot water. Approximately the same consumtion as my former home 3000 s.f. with no wind exposure. Oh & in my new home I wore shorts all winter ass my wife had control of the t-stats.
This is a great performing system, but IMO unless you are able to do it yourself, the labor & material involved is probably 20% more than stick framed construction so be prepared.

 

[begreen]

I'm a bit surprised that one would want insulation on the interior side. I'd rather have double the insulation on the exterior side and the concrete uninsulated to take advantage of the thermal mass on the interior. Do they have a system that uses form boards on the interior instead of a foam wall?

 

[SE Iowa]

BeGreen,
Check out the Quad Lock system. If I remember right, it uses more insulation on the outside for the ICF block and less on the inside. I assume this is better since the thermal mass, once heated will coast alot longer.