Petunia290
New Member
Posts:3
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| 23 Apr 2008 05:52 PM |
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Hello everyone. I am so glad that I happened to stumble upon this great site. It has been very educational and helpful. We are hoping to build our 2000 sq foot home next spring.
My first question is how strong is an ICF foundation compared to a conventional foundation? My builder is trying to talk us into building an icf home but with a conventional foundation as he believes it is stronger.
My second question is... I know that we will save a lot of money in heating by going with the icf and also if we were to go with geothermal. My concern is...will we save enough to make up for the cost of both?
We originally wanted to go with icf, geothermal and infloor heating but our builder estimated that it would cost us around $70, 000 more for all three which we would not get back enough in savings to make it worth it.
Thanks for your time.
Monia Butler
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wes
Advanced Member
Posts:810
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| 23 Apr 2008 06:19 PM |
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Is your builder talking about using a conventional poured concrete or cmu foundation below grade and then switching to ICFs above grade? If so, that's just plain dumb. In my experience, an ICF vertical wall assembly is much stronger than either equivalent thickness poured walls or filled cmu.
Without more detailed info, I would not think that spending the additional $70,000 would be worthwhile.
How do the additional features breakdown, cost wise? |
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| Wes Shelby<br>Design Systems Group<br>Murray KY<br>[email protected] |
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bobgieser
New Member
Posts:33
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| 23 Apr 2008 07:41 PM |
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If conventional foundations in your area are CMUs, then Flat panel ICf systems( 90 % of the systems out there, is way more stronger. If a regular poured wall system is conventional in your area (take the wood or metal forms down the next day or so) then flat panel ICFs are again way more stronger (That's Kentucky talk for: "way mo betta"!!)
Reason being is that when an icf wall is poured and is curing, the EPS panels stay in place and a slow moist cure is taking place allowing the 3500-4000 psi concrete to cure out at 5500 or more in 28 days.
Hope this helps. Listen to Wes |
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| Bob Gieser<br>Sales and Technical Support<br>Holdfast Technologies<br>Master Distributor for Nudura ICFs<br>(916) 214-4398-cell |
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gncc35
New Member
Posts:31
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| 10 Aug 2009 11:22 AM |
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I want to know where everyone on here is getting their information that is saying that an icf wall out performs a cmu wall in strength and insulation value for a basement wall. First off the strength factor, what size of cmu wall and icf walls are you comparing. Are you factoring in any reinforcement used in the cmu wall. Because I assume your icf walls are using reinforcement. Secondly when you are comparing prices are you comparing same wall thickness. Thirdly when you are calculating r value and u value for underground walls what energy savings would you see when the temperature variance from the external wall to the interior wall is so minimal, when in fact it may cost even more money to cool icf wall construction underground especially in warmer climates, because the cooler temperatures of the ground would not transfer to the inside. But in reality if you had absolutely no openings in your home this might make a difference but the fact is most windows are not going to exceed much better r value than 4 or 5 so how much difference could it make in the overall picture if your walls go from an r 19 to r30. The r value in the walls of a structure is minimal compared to attic of your home. Just talk to the experts like owenscorning about that. cmu has been used for many more years than icf and has proven itself over and over, and if properly constructed with vertical and horizontal reinforcing,will stand the test of time. Why do you think it is still the product of choice for all of our childrens school buildings. Now for the interior finish, what if you don't want finish the icf for a basement. How hard is it to wash the foam. Does the foam peel and flake off like all other foams I have seen. Will rodents and bugs dig on the foam. Will ants build nests in it. A painted cmu is cheap and nice looking. Can you just paint the foam? Everyone on here is quick to talk about the possible advantages but not the disadvantages. |
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renangle
Basic Member
Posts:304
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| 10 Aug 2009 12:07 PM |
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Hello Ms. Butler,
If you are going to build a 2000 sqft house and lets assume that you do the basement and above grade walls with ICF, I would not put in the geothermal hvac or the radient floors. Yes, they are nice, but you subject yourself to a diminishing return in my opinion. If you build the house with ICF and its 2000 sqft, I believe that your heating and cooling cost would be somewhere around $65 - $70 a month (depending on where you are of course), but for the sake of argument, lets just say its at $90 month. If you put in a geothermal, lets knock the $90/mo in half to $45/mo. That's $45 a month you will save or $540 a year. Multiply that by 10 years and you are at $5,400 in savings over a high efficiency SEER HVAC. As you can see it will take you a lifetime to get to the break even point for the geothermal. Once an ICF house gets to a particular size (10,000 sqft plus), I would contend that combining ICF and geothermal will have a diminished rate of return on the investment. 10,000 sqft may even still be too small.
Some people really want geothermal and that's great, but I personally don't believe the numbers work. I will choose not to get into the CMU debate.
renangle
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wes
Advanced Member
Posts:810
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| 10 Aug 2009 03:52 PM |
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gncc35,
I am totally surprised by your opening statement. I think the best answer is: 'Common Knowledge'.
If you honestly believe that a CMU basement wall can be equated to an ICF basement wall for habitable living space, I can only conclude that you have no experience with ICFs. The differences in living conditions between the two are pronounced.
As to your statement concerning school construction, in my area, ICFs have proven to be so much better for the quality of school buildings, that the state DOE is considering making it mandatory that all new schools be built with ICFs. |
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| Wes Shelby<br>Design Systems Group<br>Murray KY<br>[email protected] |
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gncc35
New Member
Posts:31
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| 10 Aug 2009 07:57 PM |
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By just saying common knowledge does not address any of the questions at hand! |
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gncc35
New Member
Posts:31
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| 10 Aug 2009 09:43 PM |
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wes, also yes it is common knowledge that a slow cure on concrete normally ends with a stronger psi, but there is also thousands of variables that most don't consider. I am sure a concrete man could enlighten this but more important is the concrete slump, how long it set in mixer, air content, was it vibrated properly, how much water was added to get the concrete to flow, all these variables play a part in concrete strength. also if you are saying it makes a difference in strength in the finished product between 4000 and 5500 psi why not just order 5500psi concrete? Or better yet if strength is that big of concern why not just go up a size on the wall thickness like you would get with a formed wall or a cmu? |
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gncc35
New Member
Posts:31
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| 10 Aug 2009 10:03 PM |
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can anyone tell me what the typical below grade wall size in an icf wall is used. the normal cmu below grade in our area is 12" the normal formed wall is 10" the normal cmu cavity is 6" does anyone have any tests that would compare equal exterior wall dimensions with equal reinforcing. example 12" cmu vs 12" formed poured vs 12" icf with 6 or 7 inch cavity? Just a hunch but I am willing to bet the icf would come in last because if all were reinforced equally the wider stance of the other two would outweigh the advantages of the slower rate of cure on the concrete. another huge question about icf if a icf contractor never pulls off the forms how are you to know if the concrete was completely placed in the wall properly without large voids? like I said I do not know alot about Icf walls and these are all legit concerns everyone should consider. |
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scicf
New Member
Posts:67
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| 10 Aug 2009 10:39 PM |
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Usually a six inch or eight inch cavity icf is used. The rebar is truly the strength of a concrete wall, whether it be icf or poured. The question in regards to consolidation is true-if a hack does the job. Those of us who back our homes make sure things are done right, without the homeowner or inspector hanging over our shoulder. Consolidation is foremost on my jobs. The old adage "You can build a million bridges and never be known as a bridgebuilder, But you suck one @#$% and your a @#$sucker for life" is true in homebuilding. |
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dmaceld
Veteran Member
Posts:1465
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| 10 Aug 2009 11:07 PM |
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gncc35,
I've never seen a CMU basement wall that didn't leak water. It's easiest to have a water tight basement wall with ICF, although it can be done with poured, or with the right stuff, CMU.
Think about labor for a minute. CMU are labor intensive, and no where near as easy for a DIY to do as an ICF wall. To achieve the same strength with CMU you've go to fill it with concrete after it's stacked. An ICF or ordinary poured wall form will be much easier to fill. Unless the basement walls are awfully deep I would think the only reason you see 12" CMU being used is to achieve proper strength against the backfill without filling the cavities with concrete. 6" poured or ICF will do the same.
There was a message here a few months ago where someone said they built an ICF wall about 4 times faster than a crew near by built a CMU wall. Same size crews.
R values of the walls do matter, regardless of what owenscorning says. I just looked at one of the heat load calcs for my house. 12% of the heat loss was through the ceiling, 11% through the floor, and 77% through the walls. I don't have a break down handy about what the % is through the wall proper and how much through the doors and windows. I estimate not more than 40% of the 77% is through the doors and windows.
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| Even a retired engineer can build a house successfully w/ GBT help! |
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dmaceld
Veteran Member
Posts:1465
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| 10 Aug 2009 11:15 PM |
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Posted By gncc35 on 08/10/2009 9:43 PM
all these variables play a part in concrete strength. also if you are saying it makes a difference in strength in the finished product between 4000 and 5500 psi why not just order 5500psi concrete? Concrete strength has been discussed in this forum quite a bit. In a wall in a house the only real impact of concrete strength is all secondary, i.e., the effect of slump, which matters a lot, and the effect on water permeability, which is a concern for below grade walls. As a practical matter 2000 psi concrete will hold up the house just as well as 6000 psi concrete. Only in unusual situations would it really make a difference.
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| Even a retired engineer can build a house successfully w/ GBT help! |
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gncc35
New Member
Posts:31
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| 11 Aug 2009 12:50 PM |
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The statement i have never seen a cmu basement that didn't leak is not a fair statement. First off most cmu basements were never covered by the sheets of waterproofing membrane that must be used on icf there is no other choice, where with cmu you can apply a waterproof membrane directly to the structural wall, then you can also apply the same process everyone is using on the icf wall, you could also go above and beyond and spec an intregal water repellant in the cmu. as with anything if it is not installed properly you will have problems. If an icf is not installed properly I can assure you it will leak. also on an icf if you were to accidentally puncture the waterproof membrane while backfilling what defense do you have against water. If i were using icf I would want an intregal water repellant put in the concrete mix. as for your next statement, i read on one of the companys website that a nonreinforced 11 5/8 cmu unit is around the same strength as a 6 " cavity icf wall why would you use anything less than a 12" cmu, for starters you would not need the extra expense of the reinforcing rod, secondly you have just formed a brick ledge. as far as stating a do it yourself project, i read on the header topic that icf to be reinforced properly you need some sort of special expensive bracing, it also says a first timer will almost always have crooked walls. also back to the earlier subject you said to achieve the same strength as icf you would have to core fill block with concrete, isn't that what you are doing with the icf blocks?you said that a 12" cmu would be awfully deep, what is awful about that the icf wall exterior dimension is just as deep! you stated that a icf wall went 4 times faster, what were the crew sizes. i have seen cmu mason take as long as a month on a job and i have seen them take as little as 2 days!You said your house has 77% heat loss thru walls. first 77% of nothing is nothing secondly was your house properly constructed. Way to many variables to be making those broad statements> |
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dmaceld
Veteran Member
Posts:1465
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| 11 Aug 2009 01:31 PM |
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Posted By gncc35 on 08/11/2009 12:50 PM secondly was your house properly constructed. Damn right it was!! I'm done!
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| Even a retired engineer can build a house successfully w/ GBT help! |
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wes
Advanced Member
Posts:810
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| 11 Aug 2009 03:55 PM |
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gncc35
I have been in residential construction for almost 35 years. During the first 20, I spent a lot of my time dealing with required repairs on basement walls (CMU and poured). It was so bad that I would not take on a new construction project that involved a basement, period. Then I saw my first ICF basement. It was a revelation. The damp, musty dungeon had been replaced by a climate that was warm, dry and livable. I am a proponent of ICFs because I have seen the vast difference in quality of life between ICF and CMU construction.
You know, I have only met 2 people who firmly believed that CMU construction was superior to ICF construction. The first had never seen an ICF installation. The latter was a certifiable idiot. Which one are you?
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| Wes Shelby<br>Design Systems Group<br>Murray KY<br>[email protected] |
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gncc35
New Member
Posts:31
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| 11 Aug 2009 11:34 PM |
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all this name calling and still no real answers. How many of these so called repairs were properly built cmu and poured walls. Correct me if i am wrong but a poured wall is basically the same as icf minus the fact on icf you leave the forms which if i have read and understand correctly are not waterproof, so the only thing that makes an icf waterproof actually has nothing to do with the icf at all. the only thing is now there are manufacturers out there making a membrane to apply to the wall to make an icf waterproof, and the icf manufacturers are making recomendations to use these products. Only difference with poured walls and cmu there are no directions for proper waterproofing, in fact as I said earlier there is ways to make cmu and poured walls more waterproof than icf because with these two options you can first apply coatings directly to the concrete surface, also you can visually inspect the structural surface for possible voids. Yeah, go ahead call me idiot, then read the numerous other posts on here about wet basements with icf walls. I bet those people are wondering if they made the best choice. ps. if you find an icf manufacturer that claims there wall is waterproof without any further treatment to the exterior let me know. |
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gncc35
New Member
Posts:31
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| 11 Aug 2009 11:54 PM |
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guess i made him mad. The only point i was trying to make is in earlier discussions there was an agreement that a properly constructed stick frame with extra attention to proper building practices performs just as well as icf when it comes to energy effeicency.In a typical home if you had no insulation at all in the walls or in the attic there would be a much greater heat loss thru the attic not the walls. Also, what is the best r value anyone has seen in a window? 4,6,8 at best. if a home has alot of windows what does it matter that a wall r20 vs r13. and actually after saying all that r value really means absolutely nothing in energy savings in a home it is the u value that really matters, at least as far as windows go and i assume as goes with anything else. For example rvalue on windows is a test at the center of the glass, you could have an r value of 50 and not have any weatherstripping letting air pass freely to the inside. this is where u value comes into play it is the overall value of the window as a unit. so if i were to figure the u value of a wall it would include doors and windows. don't dwell on individual r values you have to look at the whole picture. |
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Jay23
New Member
Posts:13
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| 14 Mar 2011 03:40 PM |
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Most people are smart enough to look at tests and make their minds up you clearly don't want to as you are a CMU installer.
It is so laughable that you think CMU will stand up to ICF, look at blast tests, and pressure tests done by the DOD and I'm sure even you can see the benefits after that.?
I'm sorry mate but the rest of the world knows and you are willfully ignoring the facts that are available and standard knowledge.
ICF has no dew point like block or poured (Thats where water & air meet=MOLD) Insects don't eat EPS but will go through the cracks in your CMU. I poured a 20' high racquetball ct below grade wall with no problems can you do that with CMU?
ICF tested to 285 MPH lateral can CMU do that? After hurricane Katrina did you see the picture of 3 ICF homes still intact and thousands of CMU and wooden structures gone!!
Being willfully ignorant and not doing a real investigation into future building materials is why people still use wood and why all of those homes got wiped out in New Zealand & Japan, ask any of those people if they would have it all over would they use you or me to build their home...Thats Point blank. |
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gncc35
New Member
Posts:31
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| 15 Mar 2011 12:10 PM |
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Posted By Jay23 on 14 Mar 2011 03:40 PM
Most people are smart enough to look at tests and make their minds up you clearly don't want to as you are a CMU installer. It is so laughable that you think CMU will stand up to ICF, look at blast tests, and pressure tests done by the DOD and I'm sure even you can see the benefits after that.? I'm sorry mate but the rest of the world knows and you are willfully ignoring the facts that are available and standard knowledge. ICF has no dew point like block or poured (Thats where water & air meet=MOLD) Insects don't eat EPS but will go through the cracks in your CMU. I poured a 20' high racquetball ct below grade wall with no problems can you do that with CMU? ICF tested to 285 MPH lateral can CMU do that? After hurricane Katrina did you see the picture of 3 ICF homes still intact and thousands of CMU and wooden structures gone!! Being willfully ignorant and not doing a real investigation into future building materials is why people still use wood and why all of those homes got wiped out in New Zealand & Japan, ask any of those people if they would have it all over would they use you or me to build their home...Thats Point blank. For starters I am not a cmu installer you just assumed that. Secondly you can preach strength about icf all you want but if someone reinforced the cmu with as much steel that is required in an icf wall the cmu would be way stronger, also if you added 2" of styrofoam to the cmu you would have all the necessary r value you would need. What makes you think my cmu has cracks. What kind of mason leaves cracks for bugs?It is standard knowledge a well constructed icf vs a half butt constructed cmu would be stronger but if you invested as much money in the cmu as the icf cmu will finish on top every time. |
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icf4life
New Member
Posts:20
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| 15 Mar 2011 02:25 PM |
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"For starters I am not a cmu installer you just assumed that. Secondly you can preach strength about icf all you want but if someone reinforced the cmu with as much steel that is required in an icf wall the cmu would be way stronger, also if you added 2" of styrofoam to the cmu you would have all the necessary r value you would need. What makes you think my cmu has cracks. What kind of mason leaves cracks for bugs?It is standard knowledge a well constructed icf vs a half butt constructed cmu would be stronger but if you invested as much money in the cmu as the icf cmu will finish on top every time. "
Well I should not even dignify this statement with a response. But if you are not a cmu installer it would almost be impossible to know the pros and cons. I install both as well as poured walls and have been for over ten years and literally have hundreds out foundations under our belt, it is not comparable ICF's are better in every compacity and its not close. I dont think I am the first contractor on here to say this, I would trust the guy who does it every day. If cmu's were better I would be installing more of them, its common sense. |
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