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ICF's really better than stick-built?

Last Post 18 Aug 2009 12:18 PM by Jerry Coombs. 60 Replies.

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pbrane

Basic Member

Posts:130

28 Jul 2009 10:13 AM
I was talking to an EnergyStar consultant this morning and he was dissing ICF's as being too expensive and not worth it. IT could be the typical ignorance of the subject, but I keep hearing this. How big is the cost of concrete (which I would think is low now) in the cost equation? ALso, Focus On Energy (Wi's state energy consultant program) also just told me that they don't see any big difference between ICF and stick construction. So I'm back on the fence again.... -m

dwangle

New Member

Posts:78

28 Jul 2009 11:18 AM
That is interesting. I have talked to approximately 5 energy star auditors and every one of them have told me that an ICF house will outperform stick build every time they test one. Not by just a little - quite a bit better. I was told by one auditor that he went to test an ICF house that he thought would be way too large for the blower door test. He said not only did it test good, but it started sucking the doors in off of their seals and they had to take greater measures of holding the doors closed. Another auditor I talked to said he recommends ICF to everyone he talks to. Yet another auditor said one ICF house completely shattered his record of all the houses he has tested. That makes me wonder - Have the consultants you are talking to at all been around an ICF project? Do they have stock in lumber companies? :) I would think common sense would tell you that a solid wall would outperform a wall with thousands of holes in it. But then again what do I know about common sense. :) I say you need to talk to more Energy Star Professionals. I did a quick figure on the cost of concrete. Concrete is about 17% - 19% of the cost of an ICF wall. That is what I came up with. That could probably be debated. BTW, even if it wouldn't perform better energy wise, isn't it nice knowing you are in a house that won't burn or blow down? Just a thought. The reason I am so fanatical about it is that I live in an ICF house and there is no way I would ever think about living in a stick home. That is my two cents for today.

ICF for life

pbrane

Basic Member

Posts:130

28 Jul 2009 12:01 PM
Hi and thanks for the excellent reply (and pep talk).. Yes, I guess I should talk to more consultants. It may be, as I said, just ignorance. But the guy I spoke to this morning said that he tested a house built by my ICF guy once and it didn't test well. I'm more worried about why Focus on Energy would say they're no better than stick. I agree that it makes sense that you have a lot less holes/seams etc with ICF's. I also like the STC ratings (sound). Another reason is that I want a dry, warm basement, which is more difficult to achieve with standard foundation, I believe....... thanks again. -m

ICFARXX

New Member

Posts:40

28 Jul 2009 07:04 PM
Sounds as if your energy guy is just plan wrong. I would get another guy and if this guy works for the only company around you then I would request another person. Lets see you have R-50 walls vs what R- 20 or a little higher. One thing you might want to ask the guy is how was that one house he tested with ICF attic insulated.

dmaceld

Veteran Member

Posts:1465
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28 Jul 2009 09:44 PM
Oak Ridge National Lab does research on building envelopes. There's a lot of info and reports on their site. Here's a link to one of the reports. http://www.ornl.gov/sci/roofs+walls/research/detailed_papers/thermal/index.html In the conclusion is this comment: "Whole building possible energy savings in houses built with ICF walls were estimated as well. Three houses with 74 - 279 m² (800-3000 ft² ) of floor area were simulated for this purpose. It was found that for ten U.S. locations, ICF walls of R- 2.6 and 3.5 m²K/W (15 and 20 hft²F/Btu), the average potential whole building energy savings (ICF house vs conventional wood-framed house) can be between 6 and 8%." Take a tour of the Oar Ridge site. But don't expect to find absolute clear cut answers 'cuz there ain't none! Also check out the SIP forum here on GBT. What you'll learn is that in a mild climate without significant daily temperature swings a frame wall can be made to have a insulation performance on par with ICF. They can also be sealed as tightly as ICF, but not without substantial effort. Your consultant may be correct, to some extent, but I'd be willing to bet he couldn't explain why. If he is dissing ICF without good clear cut explanations, it sounds like he's speaking from a substantially biased viewpoint. If you have the time, and can afford to do it, have a preliminary design of your house done with both ICF and very well insulated air tight frame construction approaches. Then get some preliminary cost estimates from several builders, both frame and ICF. Make sure the frame builders understand energy efficient construction methods. Most don't. That, in my opinion, will go a long way to getting you the answer you want. My guess is there won't be a huge difference, but the frame may be less. Then you've got to consider the other benefits of ICF such as sound isolation, fire resistance, storm protection (you are in tornado country, right?) and the temperature stability the concrete walls provide. Good luck researching, and try not to scratch your head bald while you figure out what's best for you!!!

Even a retired engineer can build a house successfully w/ GBT help!

PanelCrafters User is Offline

Advanced Member

Posts:680

29 Jul 2009 07:15 AM
Posted By ICFARXX on 07/28/2009 7:04 PM ...Lets see you have R-50 walls vs what R- 20 or a little higher. Please! Don't use that as an argument...You'll lose every time .

....jc<br>If you're not building with OSB SIPS(or ICF's), why are you building?

pbrane

Basic Member

Posts:130

29 Jul 2009 09:14 AM
Hmmm... Only 6 to 8% better than stick-frame? That's not anywhere near the claims I've seen of 50 to 70% savings. 6 to 8% seems really low. My ICF guy would also say that as the stud wall house ages, it will twist and wrack in the wind, caulking will fail, the house will get leaky etc. So maybe they should also test after 10 or 20 years to see how they compare.. I'm still sold on ICF's if only for the high STC numbers. Thanks for the great responses. -m

dmaceld

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29 Jul 2009 09:45 AM
Posted By pbrane on 07/29/2009 9:14 AM That's not anywhere near the claims I've seen of 50 to 70% savings. Ahhhh, now you've hit on the real problem, sorting out claims from fact. That's a problem that is confronted in every aspect of home construction, not just ICF walls vs. frame walls. Fortunately, in some areas the sorting is easier!! If you keep an open mind, think rationally, and don't let yourself get frustrated, it will be a very challenging, enjoyable, stimulating, and rewarding adventure!!

Even a retired engineer can build a house successfully w/ GBT help!

dwangle

New Member

Posts:78

29 Jul 2009 12:16 PM
This was on the same site. Why the different claims? "In 1999 a field investigation on thermal mass effect in residential buildings was performed by the NAHB Research Center [NAHB RC-1999]. NAHB RC evaluated three side-by-side homes 102 m2 (1098 ft2) of floor area to compare the energy performance of Insulated Concrete Forms (ICF) wall systems versus traditional wood-framed construction. All three homes had identical orientation, window area, roof construction, footprint, duct-work, and air handler systems. This research provided another experimental evidence of the superior energy performance of buildings constructed using massive wall materials. A 20% difference was noticed between the ICF house and the conventional wood-framed house’s energy consumption." pbrane- Note the different word selection. The difference between the 50% and 20%? The 50% is the HVAC cost savings. The 20% is total energy savings. That is my impression anyways. Think about it, r-40 (yes r-40 - we have had independent engineers test it to disprove the claim in KY) compared to r-20. Twice the r-value would probably mean half the heat/ac, right? I do think the r-50 claim is a little far fetched, but r-40 very attainable.

ICF for life

dmaceld

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29 Jul 2009 12:28 PM
Posted By dwangle on 07/29/2009 12:16 PM This was on the same site. Why the different claims? Location may be one reason. Possibly the frame home was built with usual construction techniques which are not as air tight as ICF. Also, these were real houses. The report I quoted from says "simulated", i.e., computer modeled. The modeled house was most likely the ultimate in insulation and air tightness. We need to be careful in comparing frame vs ICF. There's no doubt that an ICF house will inherently be much better than the usually built, (in the past anyway), frame house, but not necessarily much better than a very well built frame house. But, IMO, you will achieve a well insulated air tight house with ICF with substantially less "extra" effort than you will with frame.

Even a retired engineer can build a house successfully w/ GBT help!

dmaceld

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Posts:1465
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29 Jul 2009 12:52 PM
Pay attention to air tightness of the home. When you do heating/cooling load calculations and vary the air changes per hour input you will see significant changes in the load. The goal is to have as tight a house as possible, and then add a ventilator to provide air changes as required to maintain healthy air. Manufactured homes are stick frame, and for years have been built tight. They also have ventilators included. My brother, who spent years in the mf'd housing business, said one time, "One thing owners of mf'd homes do not complain about is the heating and air conditioning bill." I wonder sometimes if I wouldn't have been better off financially to have bought a mf'd home rather than build this ICF home! But I don't regret one bit building this ICF home.

Even a retired engineer can build a house successfully w/ GBT help!

Jerry D. Coombs, PE User is Offline

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Posts:138

02 Aug 2009 11:25 PM
As it was pointed out the Oak Ridge tests were fairly inconclusive. It's been stated that they stick frame homecanapproach the level of energy efficiency as that of an ICF. Geographical area will influence the bottom line. Of course there is a lot of debate around that statement. The point is that the level of effort in detail and QC in the Oak Ridge stick frame homes was phenomenal. If you want a stick frame home to that level of energy efficiency you have to include the costs of that effort and an independent QC agency, because the typical stick frame older just can't do it. With ICFs that energy efficiency is inherent. Any competent ICF builder will get similar results as most others in terms of energy efficiency. But is energy efficiency the only reason you want to look at ICFs? When you consider all of the other benefits of ICFs, in my opinion it's a simple choice. Stick frame cannot begin to touch ICFs in terms of sound insulation. There is just no way. And over time, in almost all areas, the foundation of a stick frame home will move enough to affect air infiltration among other things. And ICF home is inherently rigid and it's not going to have the same type of movement. I'm sure y'all can come up with other things from sales brochures too... Me? I just like ICF's

Jerry D. Coombs, P.E.<br>Coombs Engineering, P.C.<br> <br>You can have with quality; You can have it fast; You can have it cheap. Pick any two.

Buntly

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Posts:162

03 Aug 2009 06:20 AM
Amen!,............couldn't have said it better myself! Bunt

Bunt

icfcontractor User is Offline

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Posts:277

03 Aug 2009 09:23 AM
Jerry, You are right on target. Any building done right will be more energy efficient than the typical "slam bam thank ya maam, low bidder subs galore project." Comanies that are low bidders usually are, because of a few factors, they either missed something in the plans or they cut corners. When you get a whole group of companies doing that on a project, the project is the one that suffers from poor installation to just plan missing parts or steps. And people don't be confused, in my experience most building offcials are woefully lacking in their knowlege and ability to do their job right, so when you pass a city or county inspection, that does not mean it was done right. It means you got a check mark from the local jurisdiction. ICF buildings can and should be more energy efficient than the most current practices of building with stick. Jerry is right, a well managed, independantly verified building, will be a great building. ICFs make that easier. Some of the advantages of ICFs that are not listed are duribility, strength, and speed of construction. HUD lists current stick built homes properly maintained as 30-40 year structures (how long is a mortgage?) and current concrete homes as 100+ year buildings. Right there you are getting 2 1/2 to 3 times the longevity out of your home. Reducing maintenance costs and time to maintain it. Stength, an ICF home is just stronger than a stick home, plain and simple. Speed of construction, A knowlegable well rounded ICF crew should be able to keep up with or out perform a framing crew and foundation crew in a head to head competition. Then add to that when the ICF crew is done, the walls already have a quality vapor barrier and quality insulation job. My thoughts ICF Contractor

toddm

Veteran Member

Posts:1152

05 Aug 2009 04:05 PM
ICF is a definite gamble in one sense. If you resell inside 10 years, you aren't likely to find a buyer willing to pay the premium you paid for ICF. Ten years is guesswork on my part, based on my assumption that home price appreciation will be modest even after the housing market turns around. For the long run, there is no reason to guess about the energy efficiency of wall systems. UCLA offers free modeling software that allows you to try any number of alternatives based on your climate, and your house design, building orientation and window and door choices. You'll download weather data from the nearest NWS station, typically within 50 miles. www2.aud.ucla.edu/energy-design-tools/ ICF is no winner in my case: 32 kBTU/sf/yr vs 33 kbtu for 2x6 stud walls with exterior foam sheathing. The dollar savings, at $40 a year, is less than compelling. This is a small house with lots of windows facing south, and in a part of world where UCLA's HEED software assumes little benefit from the dynamic benefit of thermal mass (which is how ICF buffs ramp up nominal R20 to "effective" R40 toR50.) Your results will vary. UCLA's Climate Consultant 4 will help you choose an appropriate energy strategy for your climate. Yes, HEED's comparision of ICF and stick built assumes that the stud walls will be tight, but this isn't rocket science. Give me a caulking gun and week before the drywallers show up, and I'll give you an tight house. Or hire a spray foam contractor to strengthen stud walls and seal them at the same time.

gncc35

New Member

Posts:31

10 Aug 2009 11:40 AM
Posted By dwangle on 07/28/2009 11:18 AM That is interesting. I have talked to approximately 5 energy star auditors and every one of them have told me that an ICF house will outperform stick build every time they test one. Not by just a little - quite a bit better. I was told by one auditor that he went to test an ICF house that he thought would be way too large for the blower door test. He said not only did it test good, but it started sucking the doors in off of their seals and they had to take greater measures of holding the doors closed. Another auditor I talked to said he recommends ICF to everyone he talks to. Yet another auditor said one ICF house completely shattered his record of all the houses he has tested. That makes me wonder - Have the consultants you are talking to at all been around an ICF project? Do they have stock in lumber companies? :) I would think common sense would tell you that a solid wall would outperform a wall with thousands of holes in it. But then again what do I know about common sense. :) I say you need to talk to more Energy Star Professionals. I did a quick figure on the cost of concrete. Concrete is about 17% - 19% of the cost of an ICF wall. That is what I came up with. That could probably be debated. BTW, even if it wouldn't perform better energy wise, isn't it nice knowing you are in a house that won't burn or blow down? Just a thought. The reason I am so fanatical about it is that I live in an ICF house and there is no way I would ever think about living in a stick home. That is my two cents for today. Are you saying that a house built with icf won't burn down. Maybe i don't understand icf I thought you still used wood for the floors and roof . and shingles. Is the foam used on the Icf fireproof,or smokeproof, which is what normally kills the people in fires not the flame. Isn't wood studs still used for furring?

gncc35

New Member

Posts:31

10 Aug 2009 12:24 PM
Posted By icfcontractor on 08/03/2009 9:23 AM Jerry, You are right on target. Any building done right will be more energy efficient than the typical "slam bam thank ya maam, low bidder subs galore project." Comanies that are low bidders usually are, because of a few factors, they either missed something in the plans or they cut corners. When you get a whole group of companies doing that on a project, the project is the one that suffers from poor installation to just plan missing parts or steps. And people don't be confused, in my experience most building offcials are woefully lacking in their knowlege and ability to do their job right, so when you pass a city or county inspection, that does not mean it was done right. It means you got a check mark from the local jurisdiction. ICF buildings can and should be more energy efficient than the most current practices of building with stick. Jerry is right, a well managed, independantly verified building, will be a great building. ICFs make that easier. Some of the advantages of ICFs that are not listed are duribility, strength, and speed of construction. HUD lists current stick built homes properly maintained as 30-40 year structures (how long is a mortgage?) and current concrete homes as 100+ year buildings. Right there you are getting 2 1/2 to 3 times the longevity out of your home. Reducing maintenance costs and time to maintain it. Stength, an ICF home is just stronger than a stick home, plain and simple. Speed of construction, A knowlegable well rounded ICF crew should be able to keep up with or out perform a framing crew and foundation crew in a head to head competition. Then add to that when the ICF crew is done, the walls already have a quality vapor barrier and quality insulation job. My thoughts ICF Contractor Are you saying that an icf home is good for 100 years and a stick frame is only good for 30 to 40? first has icf been around that long. secondly. what are they saying is deteriorating on a stick frame. I am also wondering what the extra weight of the icf walls do to the footing Do they need to be larger to accomodate the added weight? Also what is the overall wall thickness of an Icf wall. While doing comparisons are they comparing apples to apples?

dwangle

New Member

Posts:78

10 Aug 2009 02:25 PM
gncc - like I said on your other post, you need to do a LOT of research about ICF's before you bash them. It is quite apparent you know very little about the technology.

ICF for life

Jerry D. Coombs, PE User is Offline

Basic Member

Posts:138

10 Aug 2009 03:27 PM
gncc35, I try not to put statements of time in any discussion on homes. There are plenty of hundred year old stick frame farmhouses out in our farmlands. They're livable, and some very nice looking, but they're not substantial. On the other hand concrete will be around for an indefinite period of time. ICFs haven't been around long, but concrete has. Many structures for over 1000 years. The would structure wears out. Every time a strong wind blows, and you hear the structure squeaking, you're hearing nails and boards rubbing. It's a tiny bit, but it's deteriorating. You won't get that kind of deterioration and noise with a concrete home. Simple fact. And yes you'll get additional loads. It's unwise to build all but the simplest of homes, stick frame or concrete, without the input of an engineer at some point. But then again you might expect me to say that. :-) When you get to needing that engineer, give me a call. Thanks

Jerry D. Coombs, P.E.<br>Coombs Engineering, P.C.<br> <br>You can have with quality; You can have it fast; You can have it cheap. Pick any two.

gncc35

New Member

Posts:31

10 Aug 2009 08:11 PM
I am not arguing that concrete will outlast wood,in certain conditions. But in a home the wood or the concrete should never be exposed to the elements. The concrete walls are alot heavier which could cause more footer shifting and cracking, which in turn causes the walls to crack. But with icf you plobably would never notice this until it was too laqte because the foam would hide the ploblems. These are just a few of the things that icf sellers are not addressing in these forums. There is only one side being told here. I am not even saying that icf is still not the best choice , I am just saying there is alot of possible problems that need to be addressed here.