getwired
New Member
Posts:6
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| 21 Feb 2009 10:00 PM |
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Hi All,
I'd like to thank all of you for your responses to my geothermal vs concrete masonry post (aka. Limited Funds - Two Options". I am now leaning towards the option of concrete masonry.
With this said, I now have a new dilema... Our builder is an experienced concrete masonry builder, but using CMU blocks. Yet, everything I read on this site seems to indicate that ICF is better... Is this always the case, or is this regional and specific to the house specs?
Here is some information on the house:
Location: Central North Carolina (Chapel Hill, NC)
Ceilings: 9ft (all floors)
First floor: 2208 sq ft
Second floor: 895 sq ft (under the eaves)
Basement: 2208 sq ft (unfinished)
I'm trying to inform myself, yet all of this reading is just making me unsure.
Thanks in advance for any responses. |
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Alton
Veteran Member
Posts:2157
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| 21 Feb 2009 10:18 PM |
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When you price CMU against ICF, be sure to compare fairly. Consider the amount of insulation and reinforcement in each. Include the time for laying each type of block and placing of concrete in th ICF or grout in the CMU. You can use concrete block a lot of places without grout and vertical reinforcement but I would not trust it in a storm. Check out impact testing of the two systems. ICF is much stronger in many ways. |
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Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period .
334 826-3979 |
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Chris Johnson
Advanced Member
Posts:877
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| 22 Feb 2009 12:39 AM |
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ICF covers many aspects of construction
1. we are already insulated
2. we are already strapped, ready for finsih
there are others, but compared to what you are talking about thuse 2 should be reason enoug to strongly consider ICF consrruction
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| Chris Johnson - Pro ICF<br>North of 49 |
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Jelly
Veteran Member
Posts:1017
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| 23 Feb 2009 08:53 AM |
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I looked very closely at CMU, and if done right (properly reinforced and insulated) it can be an extremely strong and energy efficient method of construction. It is cheaper in overall material costs than ICF. The catch is labor. While one concrete masonry unit costs about a dollar, the labor to lay the block will cost at least that much, sometimes a good bit more. Then there is the added labor of applying insulation, something which is already complete when laying the ICF block.
I wouldn't be surprised if when it was all priced out by an experienced CMU builder versus an experienced ICF builder, that it cost about the same. The decreased labor of ICF would make up the difference for its high material cost.
Now if you have a builder not experienced in ICF, then he is probably going to want a lot more to do it that way. You might consider getting a different bid from an experienced ICF builder.
You can indeed make a perfectly safe and efficient house with CMU, but you won't find much love for it here in this forum. |
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getwired
New Member
Posts:6
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| 23 Feb 2009 08:51 PM |
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I contacted my potential builder and asked about ICF in comparison to CMU. The response I received listed a few good and bad things about ICF:
The Good:
1. Very energy efficient.
2. Technically, there is less labor involved. The wall system costs just a little more than an 8" CMU masonry wall.
3. When waterproofed, you can apply hardiplank, stucco, and stone to it.
The Bad:
1. The forms are made out of hardened styrofoam, which are not exactly environmentally friendly.
2. They cannot be used with a basement system. Note that you can have a basement though, and still use this. We can build the walls in contact with the ground with a CMU wall, and use the ICF system above grade.
3. The walls tend to undulate when concrete is poured in them. It's not a structural issue, just one of aesthetics. You never, ever pour an ICF wall at 12' in height.
Several things in this response have me asking more questions. For example, my reading has given me the impression that that ICF was ideal for building a a home with basement, that both basement as well as other floors could be built using ICF. Therefore line item 2 (under The Bad) has me wondering if my understanding is incorrect.
I would appreciate it if someone clear this up for me?
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Alton
Veteran Member
Posts:2157
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| 23 Feb 2009 09:10 PM |
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I have seen too many problems with using CMU below grade. |
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Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period .
334 826-3979 |
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TB MACS
New Member
Posts:19
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| 23 Feb 2009 09:34 PM |
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Cmu is no comparsion to ICF.Yes they can be installed below grade, we do it every day in NC.We have several multistory homes in Chapelhill that we have completed, if you would like to see them or talk to the homeowners, i would be glad to do so.As far as icf walls being straight i will put any wall we do against a cmu wall for being true,square and plumb. Also there is no problem with pouring icf walls at 12'-0" high, most of the basements we do range in height from 10'-0" to 12'-0". We have pour several walls that were 24+ high in one cont. pour,cutting pockets for concrete placement . Its all in the installer,always check references and never let your job be someones learning curve. If we can be of any help on your project, please contact us.
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STACKING THE CAROLINAS ONE BLOCK AT A TIME!
TODD BIGGERSTAFF/ TBMACS ICF CONTRACTOR |
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MDiver
New Member
Posts:56
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| 23 Feb 2009 10:02 PM |
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ICF can be used as a basement system. That is all I use for my basements now, even if we don't use ICF above grade, we are still using it for the foundation. |
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BrianW
New Member
Posts:6
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| 24 Feb 2009 05:42 AM |
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It sounds like your builder is not familiar with ICFs at all. I am building a 12 foot high basement right now on the edge of Chapel Hill and you are welcome to come see it. There is also another one on the other side of town with the same height walls and two stories above being built. I'll email you my contact info.
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tdbuilder
New Member
Posts:67
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| 24 Feb 2009 07:05 AM |
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Like in the last 3 or so post, I have to agree that you contractor is misinformed. ICFs can go taller than 12' over 20' on a couple of my jobs. Some part of the walls is almost always under ground, like stated earlier ICFs are all I use on basements now. In a couple of cases where the labor rates are high (government jobs) we would be cheaper that a cmu. |
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Jelly
Veteran Member
Posts:1017
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| 24 Feb 2009 08:07 AM |
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getwired, it would be good if you could find an experienced ICF builder for a second bid.
Like the others have mentioned, ICF is used for basements all the time. Your builder may be concerned about the foam being in contact with the dirt because of termites, but most ICF manufacturers impregnate their forms with borate to prevent that (the termites can't do any damage to ICF, but theoretically they could bore through the forms. It's not even likely to happen. The borate is added, in my opinion, just to quiet any concerns, even though those concerns aren't warranted).
The walls will undulate if not properly braced and care is not taken during the pour. This is where you need someone who knows what they are doing.
And true, as a material, hardened styrofoam is not environmentally friendly. But you have to consider where is that material being used. If it's a coffee cup that you're going to throw away after one use, then it's practically a grievous crime against nature! But if it is a building material that is meant to last forever, well that's where you want to use styrofoam. Better to last a lifetime insulating a building than a lifetime in a landfill. And besides, the CMU would have to be insulated, too. And the best insulation for CMU is external styrofoam boards (if he wants to insulate your CMU house on the inside using fiberglass, then he's not really interested in efficiency anyway). |
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colinmcc
New Member
Posts:35
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| 02 Mar 2009 06:00 PM |
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getwired, Your builder is woefully ignorant! Find another!! If properly detailed there is no reason why icf can't be used for below ground, I have done that on every house I've built since 1992. Never had a leak, nor a callback.
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Buddy Newberry
New Member
Posts:9
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| 03 Mar 2009 10:01 AM |
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I apologize for the long response to follow:
There are a few issues that must be addressed and cleared up in this Forum first and foremost. The word Styrofoam should never be associated with ICF's. None of the ICF's most commonly exhibited on this website are made of this material. ICF's are made of Expanded Polystyrene (EPS) Type 2, which is expanded by steam at 212 degrees Fahrenheit. Styrofoam or "Xboard" is created through a catalytic chemical reaction that is continuous throughout the lifespan of the product. In turn, this chemical reaction that creates the product also breaks it down over time, giving Styrofoam a limited lifespan, while at the same time releasing HFC's and CHFC's. EPS is produced through a steaming process that is powered by the efficient means of natural gas. Due to the clean and environmentally friendly nature of this production process ICF's have no trace of HFC's or CHFC's and therefore promote indoor air quality as well as energy efficiency. Subsequently, EPS type 2, or in general terms ICF's, can be labelled as a Green Product even before we start talking about energy efficiency, in-door air quality, R-Performance and Healthy Home living.
It is widely known that concrete is not a Green Product (it can be made more Green by replacing certain ingredients with more green alternatives such as Fly Ash) and even if you still don't believe that EPS is a Green product, the outcome that you get by combining these two elements together creates the most Green building system on the market. By super insulating the concrete between two panels of EPS a green value can then be given to these two products, because of the thermal dynamics, or heat sink effect that is created. It is the thermal properties of an ICF's concrete core that produces the R-Performance and overall energy efficiency of the building envelope. Therefore, because of the overall performance and green elements that are attributed to an ICF wall system, concrete and EPS can be labelled green themselves.
On another note, it is absolutely ABSURD to say that ICF's cannot be used below grade. ICF's started exclusively in below grade applications and are perhaps the cost efficient way to construct a foundation, frost wall, stem wall etc. When comparing ICF's to CMU's you are comparing a Cadillac to a Pinto, in other words there is no comparison. Yes the upfront cost of an ICF is going to be more, but the overall installed cost will be far less and the performance will be unmatched. In constructing an ICF wall system you are completing four steps in one; studding, vapour barrier, insulation and house wrap. By simply building the wall you are eliminating costly construction applications at the same time. When using CMU's you are sacrificing structural stability, insulating properties, indoor air-quality, time and money. When an ICF wall is poured it is ready for any type of interior or exterior cladding that you wish to apply. Once the CMU wall is completed you have to glue on or rest insulation and waterproofing against the wall on the exterior, install insulation and vapour barrier on the interior, and in some cases a stud wall. When looking at ICF's don't look at the upfront cost look at the INSTALLED COST. As well, there are some ICF's that have multiple web thicknesses including a 5" web like IntegraSpec ICF, that allows you to meet the same wall thicknesses of CMU's should your plans specify this detail.
Finally, plumb, straight and true walls are going to be ensured by your installer just like it would when using CMU construction. Find a good installer.
Buddy, |
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Alton
Veteran Member
Posts:2157
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| 03 Mar 2009 10:25 AM |
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Amen |
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Residential Designer &
Construction Technology Consultant -- E-mail: Alton at Auburn dot Edu Use email format with @ and period .
334 826-3979 |
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thagreen
Basic Member
Posts:283
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| 03 Mar 2009 02:37 PM |
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Nothing else to be said! Nice post buddy.
ps. you seem fired up!!lol |
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arkie6
Veteran Member
Posts:1453
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| 04 Mar 2009 01:33 PM |
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"ICF's are made of Expanded Polystyrene (EPS) Type 2"
Note that not all ICFs are made from Type 2 EPS. Several ICFs, primarily the site-assembled flat panel forms, use the higher density Type IX EPS foam. Type IX EPS has a nominal density of 2.0#/cu ft while Type 2 has a nominal density of 1.5#/cu ft. Type IX also has a higher compressive strength, higher tensile strenght, higher R value, and lower water vapor permeance.
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Quad-Lock
New Member
Posts:30
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| 05 Mar 2009 10:32 AM |
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Great post, Buddy! Re Green Aspects / Sustainability of ICFs: another important point is that typically more than 90% of emissions from buildings happen during its operation - with a big proportion from heating & cooling. This means that ICFs initially higher CO2 output from EPS + concrete (compared to framed or uninsulated walls) is offset by lower emissions over the building's lifetime. The break-even point is typically within 3-7 years compared to wood-framing - after that ICFs really shine with lower emissions and utility bills! Re EPS Types: Arkie's right - Quad-Lock's regular thickness panels are Type IX in the US (which starts at 1.8#/cu.ft - see chart or our panel specs). |
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