Looks like ICF manufacturers are now offering increased R-Value on their forms. Typically an ICF has 2.5" of EPS per side, which gives it a true/effective R-23 value. Now many manufacturers are making thicker forms or add-on EPS options. Amvic Plus now offers 3.25" EPS per side for a true R-30 value.

ICF ARTICLE

Some climate areas like Arizona, it would be overkill/diminishing returns to go above R-22 on the walls. Other cold climate areas like Northern Michigan and similar areas would benefit from higher wall R-Values.

Just thought it was interesting to see this development in the ICF industry.

I think that they should increase R value by adding a cavity for cellulose.

The Amvic 3.25" interior would make it possible to install standard gang boxes. With that extra interior depth, having horizontal knockout channels for wiring would be sweet.

The majority of insulation should be on the exterior anyway so that thermal mass attributes are maximized esp. with conrete floors tied in with ICF walls as it is all one big thermal bridge.

At high-R even EPS starts getting expensive. While the thermal performance is there, the economics are a real stretch at R48.

Calling the Amvic Plus product "a true R-30 value" is more than just a bit of a stretch- it's pure marketing BS, in practical terms, unless "true" means something other than "factual" in your dialect.

6.5" of EPS only hits -30C (-22F) AVERAGE TEMPERATURE THROUGH THE INSULATION, not at -30C outside temp.

Even the -30C outside temp is a condition few in the lower 48 see anyway- lower than the 99% outside design temp for most US locations. You're not going to see that in AZ until the next ice age. (Building your next house on a 10,000' peak in Antarctica? That would be a place where the Rvalue at -30C might be relevant, at least in the summertime. :-) )

At 115F outside, 75F inside 6.5" of EPS performs at about R24, add R1 for the concrete, another R1 for siding/finish wall and you're at ~R26 for a steady-state R. With the big diurnal temperature swings of higher-altitude AZ the dynamic effect of the thermal mass counts for something though.

Their phony charts by which theyeven at R1.5 for interior AIR FILMs:

http://www.amvicsystem.com/wp-content/uploads/2012/07/R-Value-Chart-3.30-303.gif

http://www.amvicsystem.com/wp-content/uploads/2012/07/R-Value-Chart-3.30-221.gif

Any whining about "yes, but those air films are real" blah blah blah. For apples-to-apples ALL wall assemblies have identical air films, but they don't exist in an ASTM C 518 test fixture, so they're usually ignored.

Their average R-values of the interior & exterior EPS layers don't jive with EPS manufacturer's curves either- theirs has to be something special, or they're using dramatically different densities for interior & exterior if the exterior 3.25" is R16.26 @ 22C and the interior is only R14.53 at some unspectfied interior room temp that would normally be pretty close to 22C. The R value of EPS rises as the temperature falls, yet their -30C outside condition chart gives it R13.67 for both the interior & exterior layers. It's simply not credible to me- YMMV.

For a generic view of what happens with EPS across temperature & density see:

http://texas.transconsteel.com/Products/ultraframe/docs/Other_Properties_of_EPS.pdf

Marketing distortions like that are what gives the insulation industry (and ICFs in particular) a shady reputation, and there's really no need to stoop that low. I'm sure it's a pretty good product, which should be able to compete without sending up stinking smoke screens.

I'll call it a nominal-R26 wall until they take a section of wall and test it per ASTM C 518 for a relevant steady-state apples to apples prior to dynamic effects of the thermal mass.

They are using Type 2 EPS @ 1.5 lb/cf density.
3.25" x 2 = 6.50"
R4.5/inch for Type-II EPS

6.50" x R4.5 per inch = R29.25

By "true" I meant that no thermal bridging factors to consider as compared to stick framing (20% +/-).

Nowhere did I incorporate "thermal mass" into the R-value as I know that the term makes some people go into a fit of insanity. Although I will say that Oak Ridge Labs recognizes that it plays a role in RValue but assigning a specific # is difficult due to the specific geographic applications (ie. Arizona vs. Ohio).

Jeffrey Christian (Oak Ridge National Lab) - High mass walls can really significantly outperform low-mass walls of comparable steady-state R-value-i.e., they can achieve a higher "Mass-enhanced R-value" but this mass-enhanced R-Value is only significant when the outdoor temperature cycle above and below indoor temperatures within a 24-hour period.

Assigning a climate-specific number for thermal mass is super easy, Lbear. Amvic builds a wall in an ORNL blessed hotbox, cranks the numbers through DOE 2 and voila! Pretty much every composite ICF manufacturer has done so. None of the sandwich manufacturers have to my knowledge but please prove me wrong with a link. I assume conventional ICF types prefer fiction, as in my contractor's claims that 6" Arxx is an effective R45 in so central Pa. IMHO fostering ignorance is reason to be incensed, if not insane.

having gone down the path of adding extra insulation to ICF to make it close to a frame wall, it makes an already expensive system even more expensive when compared to frame wall alternative. And no, I am not comparing 2x4 or 2x6 code min. stuff like they always do. Rather thick exterior foams, double studs, etc. Material costs of ICF vs double stud is 25-30% more, and giving you a less-than (and variable) r value ranging from r-10 and higher nob to the framed assembly. Sure, you lose out on some of the other claimed to fames of ICF such as strength, easier to achieve tightness (notice I did not say tighter) fire resistance, etc. I still think its a great basement soluation, and will use it in that application. But for me in the mid west and zone 6, above grade doesnt make a lot of sense. Sure, I am in tornado alley, but thats what we have basements for....and insurance. Goals for my designs are tight and high r. Pay off is just not there. ever.

Even though those R values numbers by Amvic are probably a bit over, they aren't by much (say 10-15%). They also used stucco siding, not a very insulating siding, so at least they didn't fudge everything.

R-value all by itself is pretty meaningless unless you can take away all effects of air infiltration and humidity. Consider the R-value of fiberglass -- it means nothing if there are air leaks or high humidity, so at least you don't have to consider that much with EPS. Within a small margin of error you pretty much know what you are getting with ICF unless the "thermal mass" or "effective R value" terms are used -- the stated R values should be pretty close to "true" values. Anyone considering fiberglass or cellulose should assume at least 2" of exterior EPS to block humidity and infiltration. Also with ICF (or SIPs) there is no extra worry or calculations related to thermal bridging due to studs.

If anyone thinks ICFs fudge R values that is nothing compared to windows. There are so many variables to consider including the process of measuring R value of both glass and frame. No real standards to speak of (in the USA).

IMHO there is one area that *underestimates* the insulating benefits -- exterior window shades and to a smaller degree storm doors. Wind blowing over a window will have a great effect on heat loss. To get a *rough* idea just look at some of the wind chill charts -- for example, a mild wind at 0F can essentially increase the heat transfer as if it's 20 degrees colder. This is never factored into any R or U values and if it was, I think more people would be getting exterior shades. I plan on getting (expensive) exterior insulated roller shades for my next house even though the published R values are only 1 or 2 I know with the winter wind they will allow the window to at least get close to its rated R\U values, reduce air infiltration (yes it is always there; it can only be minimized not eliminated), plus they stop some of the reflective\radiation heat loss and if the shade is tight enough the extra dead air space would help as well.

Interesting. At 30% more cost for the walls I'll take ICF over stick every time. You are in the weeds in the overall cost of a home. I am glad to see better stick construction as it makes better still more affordable. Also, you forgot to mention lower insurance costs and higher STC which are also in favor of ICFs as well. Regards.

insurance premiums was about $55 less a year for full ICF. Also I have not run the numbers, but I would guess the STC of a 10-12" thick dense packed cellulose wall is not to far off of ICF. But the insurance savings is nothing compared to the energy cost savings between the 2 in my heating zone 6. Texas would be a different story.

You might need to talk to a new insurance agent. If you have masonry walls (ICF) with a non combustible roof you should save much more. Also, with foam in staggered stud wall (assuming a thickness of more than 2x the stud) you will still have effectively 3 walls in series. One 2X6 wall with foam cavity, one continuous foam wall, and a second 2x6 with foam cavity. The only part of the wall that is truly continuous insulation is the center. Likely, your still around R-30 unless you add continuous external insulation to assist. Please send me one of your wall designs and I'll do me best to calc. Regards

Posted By Lbear on 12 Sep 2012 06:15 PM
They are using Type 2 EPS @ 1.5 lb/cf density.
3.25" x 2 = 6.50"
R4.5/inch for Type-II EPS

6.50" x R4.5 per inch = R29.25

By "true" I meant that no thermal bridging factors to consider as compared to stick framing (20% +/-).

Nowhere did I incorporate "thermal mass" into the R-value as I know that the term makes some people go into a fit of insanity. Although I will say that Oakland Labs recognizes that it plays a role in RValue but assigning a specific # is difficult due to the specific geographic applications (ie. Arizona vs. Ohio).

http://texas.transconsteel.com/Products/ultraframe/docs/Other_Properties_of_EPS.pdf

^^^1.5lb EPS only hits R4.5 per inch when the material is about 40F or colder.^^^ (Interpolate the density, scale to 1.5, intersect with the blue 25F line.)

So at a 70F interior temp when it's 10F outside (for a 40F average)  that's about right, but any warmer that it will be less.

Certainly in any AZ climate it's not going to average anywhere near R29.25, steady-state, and it may average well shy of R25, particularly on the sun-exposed walls.

The  R-values of the inner & outer thicknesses in the manufacturer's explanatory charts are all over the place, and not consistent with any raw EPS manufacturers R/temp data.

At 75F most 1.5lb EPS is pretty close to R4/inch.

But at 110F its closer to R3.5 per inch, which is a pretty big performance hit on, say a roof SIP.

But the annualized average will be about R4/inch give or take, for most lower-48 climate zones- a bit less in cooling dominated zones, a bit more in colder regions.  So that 6.5" x R4/inch= R26, a bit less in the summer a bit more in the winter.

I wasn't criticizing your characterization, or presuming you were incorporating dynamic factors, only questioning the manufacturer's numbers (which I had assumed you were quoting uncritically) since they in fact claimed R30. But their footnote indicates it's R30 whole-wall, including siding, concrete, finish wall, + air films, at a -30C outdoor temp, but failed to back even that up with credible evidence given the whacked numbers in their explanatory charts.

Type-II designation covers a range of densities and specs for different manufacturers' Type-II goods will vary a bit, but none spec R4.5/inch at room temp or higher.  This manufacturer specs R4.55/inch @ 40F with R4.17/inch @ 75F (which  is  pretty   typical).

I'd still call that about R4/inch average for most US lower-48 locations.  It might average something like R4.5/inch in Whitehorse Yukon or Fairbanks AK on an annualized basis (OK, so you don't have to build in Antarctica :-) ) but it will average well under that in AZ.

Posted By sharter on 13 Sep 2012 10:59 AM
Even though those R values numbers by Amvic are probably a bit over, they aren't by much (say 10-15%). They also used stucco siding, not a very insulating siding, so at least they didn't fudge everything.

R-value all by itself is pretty meaningless unless you can take away all effects of air infiltration and humidity. Consider the R-value of fiberglass -- it means nothing if there are air leaks or high humidity, so at least you don't have to consider that much with EPS. Within a small margin of error you pretty much know what you are getting with ICF unless the "thermal mass" or "effective R value" terms are used -- the stated R values should be pretty close to "true" values. Anyone considering fiberglass or cellulose should assume at least 2" of exterior EPS to block humidity and infiltration. Also with ICF (or SIPs) there is no extra worry or calculations related to thermal bridging due to studs.

If anyone thinks ICFs fudge R values that is nothing compared to windows. There are so many variables to consider including the process of measuring R value of both glass and frame. No real standards to speak of (in the USA).

IMHO there is one area that *underestimates* the insulating benefits -- exterior window shades and to a smaller degree storm doors. Wind blowing over a window will have a great effect on heat loss. To get a *rough* idea just look at some of the wind chill charts -- for example, a mild wind at 0F can essentially increase the heat transfer as if it's 20 degrees colder. This is never factored into any R or U values and if it was, I think more people would be getting exterior shades. I plan on getting (expensive) exterior insulated roller shades for my next house even though the published R values are only 1 or 2 I know with the winter wind they will allow the window to at least get close to its rated R\U values, reduce air infiltration (yes it is always there; it can only be minimized not eliminated), plus they stop some of the reflective\radiation heat loss and if the shade is tight enough the extra dead air space would help as well.

Stucco is better than you might think, because of the trapped air films. It's more air-retardent and better insulating than 6" clapboards hard-nailed to the sheathing & housewrap sans-rainscreen.

Kicking around the deficiencies of ASTM C 518 test procedures and how it overstates real-world performance for low density fiberglass is going after a pretty dead horse, but I can kick that horse with the best of 'em! :-)

The vapor permeance of 2" EPS isn't so super-low (or so high) that it can be ignored. That's true at typical ICF thicknesses too. EPS makes a lousy air-barrier (use the sheathing, which is more dimensionally stable over time), and 2" of EPS on the exterior isn't NEARLY enough to prevent moisture accumulation in wood sheathing in a 2x6 stick-built in US climate zone 6 or higher (but 3" would be- barely.) 

In cold climates EPS is great because it increases in R-value as the temperature falls, so when used as exterior sheathing it'll have on the order of 25% more R value at -10F (R4/inch becomes R5) when the heating load is high than it does at +50F when the heating load is low.  (With polyiso it goes the other direction. R6/inch nominal needs to be de-rated to about R5.3/inch @ 0F in an insulating sheathing app.)  But with EPS the converse is true for hot climates- it loses performance as the cooling load climbs. (A foil facer + an air gap can extend & improve that hot-climate performance a bit, not that it would be appropriate in an ICF.)

The air-retardency of cellulose (at any density) is 10x better than low density fiberglass, and in a stick-built adds some protection to the structural wood independent of how much exterior foam you have. At dense-pack densities it's even more true, and for thermal modeling it's as-good-as gone, but I still wouldn't skip the exterior foam for the thermal break on the framing, even in assemblies where the foam wouldn't be needed for moisture control.  Cellulose has a much stabler R over temperature than EPS or XPS or any other foam (rigid or sprayed).

Not all SIPs are devoid of thermally bridging elements, as is commonly believed. (Though the thermal bridging is pretty small in most relative to stick-framed structures.)

Don't get me wrong, I like EPS, and I like ICF, but I despise BS & overreaching mis-statements of fact (by any of 'em.)

Dana,

My main point is that 6.5" of EPS is a well-known commodity and should get 25-27R or so depending on quality\density. So saying R30 by including the rest of the wall system seems reasonable to me.

AFAIK, bad press that ICF gets regarding rvalue is related to using the "effective R value" argument about thermal mass, and not cheating by a couple r values by air film or other BS. The thermal mass effect only helps to average the temperature out over the course of a day, so under the right conditions (cold nights, hot days) it works and was abused by sales to exaggerate the rvalue. So I totally get calling the sales department on BS and half-truths.

For stucco, their chart said .13R which is nothing really as I think they would have just round up to R30 anyway. They could have said insulated siding instead and got and additional R3. I agree though that the true rvalue of stucco is probably better than .13 due to the air gap between it and the EPS.

So cost:benefit EPS currently wins factoring in air infiltration and other factors (at least for exterior layer of insulation) but there are better insulatators out there. I would rather pay more for ICFs that had better insulation and that weren't as thick, since that extra insulation cuts into floor (or roof) space, requires bigger window\door bucks, makes me question fastening ability due to shear load, and thus costs as well. I'd love to see a polyurethane ICF that gets R6\inch instead. Maybe a good price:value combination would be a bimodel polyurethane exterior and cheap EPS on interior since we cut into the interior insulation anyway for wiring etc and I don't think rvalues really matter as much on interior. Better yet, ignoring cost, if interior ICF had structural supports or made out of something else altogether such as EPS+portalnd I'd go for that even if the rvalue goes down -- that way I can hang cabinets, curtain rods, pictures, drywall, etc. without having to find strips. Yeah the blocks wouldn't be reversible but who cares.

In the future, look at aerogel. R10 or more per inch and is translucent. Translucent walls and roofs so free daylighting. Where we want windows we'll have cameras with head-tracking digital projections. That would be awesome anyway...

EPS; once the density and thickness is known, becomes an easily attainable R-Value. ICF's don't have much "wiggle room" when it comes to determining R-Values. Putting aside the thermal mass effect, once you know the forms parameters, determining R-Value of the EPS is pretty straightforward.

Now, with stick frame, there are so many variables at play that determining a true R-Value is not as easy to do. The quality of the lumber, the stud spacing, the headers, framing around doors, corners and windows, paying attention to details, sealing, caulking gaps, vapor barriers, insulation types (cellulose, spray foam, EPS, fiberglass), quality of installers, attention to properly filling wall cavities, air barriers, thermal bridging, and on and on...

With that being said, exaggerated claims are very prevalent in the stick frame and the stick frame insulation industry. Yet I don't hear the same outrage and "fact checking" against stick frame that ICF brings. The minute someone mentions ICF the insane asylum doors open and the patients come out, log on the internet and begin posting on GBT. The visceral hate that is sometimes present on this forum against ICF makes me question what is really behind the people and their positions.

I have been accused of being employed by the ICF industry. Which is not only a complete and utter lie, it shows the personal attacks and disgusting hate that is present on this forum by a few people. If you dislike ICF, fine don't use it, but don't go around making personal attacks against people. Discuss and debate it but don't make false allegations against people and personal attacks.

Each building method has its pros and cons. Some building methods are better in some climate areas than others.

I've said my 2 cents...

Great thoughts on icf's versus double wall. Nice r-value on the double wall as long as the double wall dense pack system doesn't continue to dense pack over the life of the wall system. I'm lucky I have a choice for a wall system since I still do some insulation work after 37 yrs in the business but given what i khow I would go with a icf system. 8" basement, 4" above ground wall with a 2" eps overlay on the exterior. R-60 cellulose insulation cap in the attic

And worth every penny Lbear. I don't have any problem with ICF. I'm sitting in a house built on ICF stem walls, and I will happily testify that it is superior in structure and efficiency to standard practice cmu construction and cheaper besides. I do have a problem with deception, as in your claim that quantifying the mass effect of ICF is difficult. Amvic could have reasonable numbers for representative climates around the US in a matter of months, as you well know. We don't see these numbers for traditional ICF because they are underwhelming. Thermal mass is most effective when it is exposed to the interior rather than covered with foam. So the ICF industry remains heavily invested in ignorance. How bout that mass effect? (Wink. Wink.)

No one should be more po'ed about this state of affairs than you, assuming that you get around to building that house in Arizona at some point. I've got $100 that says the best ICF wall you could build in Az is the thinnest one you can find. That is to say that R16 would interfere less with the mass effect in the most suitable climate for it in the US and be MORE efficient than R23 or R30. Less expensive too. Wouldn't it be nice if an ICF manufacturer gave you the information you need to decide?

So, fine. You are not a tool of the ICF industry. But the alternative is not overly flattering either.

For my next [hopefully last] home, I considered double wall but not for long. ICF has too many advantages to ignore, and I'm not talking about thermal mass effect or my favorite: wicking heat from the ground effect (tho I think both have some merit under the right conditions). SIP sounds good on paper but I don't want to live in a styrofoam house, plus wanted radiant floor heat and a zero-barrier layout including from garage to house and concrete floors (and thus concrete walls) just made sense for that.

Contractors and homeowners like cheap, big and fast. Who doesn't. Thus McMansions with no character but with a nice refrigerator and granite countertop. In the end they have crappy walls, windows, doors. But still better than 5 or 50 years ago. The house lasts just long enough before we pass away and most of us are fine with that since that's "what everyone else does". For those of us that know and care and perhaps also have the $ to care, we build with ICF, get the best doors and windows we can (like from Germany), geothermal, solar panels, radiant heat, passive solar, thermal mass, and perhaps try to build a smaller footprint with some architectural style.

The forcing function is that the days of cheap oil and electricity are gone, and things may get much worse. Build it right. Leave it for the next generation to enjoy. In the USA we don't really get that. We have no stone homes, castles or adobe cliff homes to give us inspiration. We are re-discovering thermal mass, geothermal and solar orientation. ICFs to me are part of this new (welcomed) renaissance.

Well put sharter.

Todd, why pick on people? Remember typical AAC doesn't have enough heat capacity to even classify as a mass wall according to ASHRAE's recent report. ICF far exceeds the minimum - in fact - the heat capacity of ICF is almost double the min for "calling" or defining a wall as massive.