There is nothing wrong with double walls and lots of affordable insulation. I built decorative CMU exterior structural walls along with steel stud interior walls. I filled the cavity between the walls with rockwool for total wall r value close to 50. Also used steel trusses, metal roof and rockwool for ceiling r value close to 70. House is just a 1800 sf single story simple rectangle floor plan. Looks like old English Cotswolds cottage that my parents live in. Total exterior wall thickness is just shy of 24”. 8” CMU and steel 2x4 stud create 15” cavity filled with rockwool. The steel studs are just for fastening dry wall and retaining the rockwool. The attic above ceiling just has 24” of rockwool. Nothing complicated here just lots of rockwool in my little castle. Originally planned to use ICF but this approach was much cheaper since I did the work myself and got free rockwool by bartering my services. Still get the nice adobe buffered thermal mass benefit as predicted on Borst ICF calculator. I figure the summer thermal mass effect makes the walls have 30-40% more effective r value than the conventional 50 value.

Lawdy, Lawdy, Lawdy, the borst icf kalkulater is a godsend. Who knew that R50 walls and R70 ceilings would be a good idea? Cutting edge.

For those of you who haven't been here much, I will share what I've seen over time, which is that this is a place of respect and entities who insist on violating it find themselves unable to contribute any further. And, there may not be a "winner" and a "loser". Sometimes, there are just losers.

"Putting all the insulation on either the outside or the inside does NOT necessarily increase the thermal mass effective R-value of ICF. In our southern Oregon Summer diurnal climates where the highs can be 110 and the lows can be 45, the effective R-value of our BuildBlock ICF which has a conventional R-value of R22 would be reduced from R66 to R44 when all the insulation is placed on either the outside or the inside."
this statement is just wrong -the whole point of insulation is to stop heat transfer from one thing to another .
putting all insulation on outside of concrete will make the walls a big thermal store ,insulation inside will allows concrete to suck heat or cold from the outside world ,thats just pure physics 101.insulate both sides it will not be a thermal store ,just a damping effect on outside temp transfer .
look at real world ,caves have a very stable temp cos they are solid rock and specific heat value of rock is around 5.1 -water is 1--which means it takes 5 times more heat to raise temp of rock by 1c than water does -yes it keeps heat longer cos it gives it out 5 times slower .
that is the true meaning and use of thermal mass --insulation has NO thermal mass -,this is why using "u" values is a far better way to understand whats going on -"u" is a value of how heat leaks out of things . "r" values are just a resistance to heat flow and there will smooth out changes temperature in house,but add little to actual insulation value .ICF is a simple +quick way to build a pre-stressed concrete house ,thats all
If you want to use thermal mass as a heat store then attach to your insulated concrete slab and insulation around outside of the complete structure .
I have never said ICF is not a good system , and will work fine for people but don,t treat me like I,m an idiot ,its not the holy grail -no system is , a blend of all will give you the best ,but once you add in cost factors +project limitations ,thats where the builder has to make honest valued judgment on what is best or right cost for him

U-factors are closely linked to "whole-wall-R" values, and like R-values are not dynamically linked to rates of temperature change. It's a static number, that doesn't reflect what happens during diurnal swings in temperature.

A thermal mass with insulation on one or both sides IS dynamic- it's a filter, dampening the effects of a change in temperature on one side that affect the temperature on the other. This affects the peak heat load by quite a bit, and to some extent the average.

Stone and concrete are not merely lumped thermal mass- they also have R-value, and also inherently filter the dynamic effects, but it's at a different rate than what happens when there is also a higher amount of low-thermal mass insulation on one side or the other (or both.)

Marketing fantasy fluff using "equivalent R" or "effective R-value" for ICF is often extreme- the particulars matter, but there IS both a peak load and average energy use benefit, though they very quite dramatically with the particular climate, season, shading factors, house shape, etc. In the end the thermal mass benefits of concrete located inside insulated walls are really secondary to the thermal effects of other elements of the house.

- like windows for one - not that they are immune from the same "marketing fantasy fluff" - an excellent term for what I was alluding to.

Obviously, there is no cookie cutter method that is best for every situation but increased thermal mass can be very effective in moderating temperature swings - esp. when combined with a free or low cost source of heat or cool. A normal 2 sided icf wall will not benefit from the potential substantial heat gain from passive or active solar, wood, pellet, etc. nor from the extended cooling benefits of just opening the windows on a cool summer evening and closing them in the morning. Where to have the insulation on both sides and where to use it on one side is different for every case but the value of thermal mass shouldn't be overlooked.

ICFHybrid, I assume you are directing that post to me since I "haven't been here much" - I can't help but notice that there was no mention of a lack of respect when it was all directed toward me. Probably just an oversight?

Thank you Dana for the great word description. U is the mathematical inverse of R and both can only be accurately applied when dealing with static temperature differences or in a mathematical simulation where dynamic temperature differences approximate static temperature differences by virtue of the mathematical simulation using very small time step increments. Unfortunately, it is difficult to discuss and understand ICF performance using words. You really need to use a validated mathematical simulation or do exhaustive temperature control room testing to accomplish this.

ICF performance does not typically align with ones normal intuition. We developed our ICF performance software largely because we wanted to better understand how ICF performs based on where the insulation was placed and because we highly doubted the claims being made at the time by ICF companies...especially that ICF would have a much larger effective R-value compared to its conventional R-value in a static much colder climate than the desired indoor temperature. At the time we reasoned that ICF would perform in a similar fashion to an electrical inductor, namely that it would tend to pass more heat during static temperature differences and less heat during dynamic temperature differences. This was found to be true and the results of our parametric analysis is summarized in our ICF performance software instructions.

Several years ago we had a very lengthy discussion about ICF effective R-value in general and also about our ICF Performance software and I see no reason to repeat it again for the new readers who are actually interested in understanding the engineering, math and science associated with this subject and our ICF performance software:

GBT ICF Effective R-value Discussion

And here’s the link to the ICF Performance software for those who want to further validate it in their climates:

Borst ICF Performance Software

Please carefully read the associated instructions before using the software.

Again, we definitely don’t believe that ICF is the best solution for all locations and climates. It is just one of many solutions. And we don’t have any affiliation with any ICF companies although we have constructed many buildings using ICF from several different ICF companies. We largely just detest companies and people making false bad or good statements about ICF or other products and design methodologies. People really need to first research the facts and get educated...and the Internet isn’t always the best place to accomplish that.

I don't want to sound disrespectful but doesn't that sound like the "Marketing fantasy fluff" that Dana 1 was just speaking of? It uses the same terminology. It seems to serve to intimidate the prospective DIY home builder who could understand the concept of stacking lego blocks but not all this verbal and mathematical mumbo jumbo that Dana 1 referred to so eloquently. I tend to raise an eyebrow when the person with all the questionable answers also sells the solutions. Like all things, It's buyer beware.

A mathematical model isn't marketing fluff, nor is it mumbo jumbo. But it also isn't user-friendly or intuitive.

Modeling of mass effects and rigorous vetting the models against both laboratory and real world in-situ testing has been going on at the Oak Ridge National Labs for a few decades now, but the analysis & data would put most people to sleep.

I'm not sure the average person would be able to put the Borst freebie calculator to good use (but some could) but in the end I suspect most won't be making critical design decisions with it, whether accurate or not. Like a lot of thermal modeling (even fairly unsophisticated Manual-J type models) there's a serious garbage-in = garbage out problem, independent of the accuracy or intended use of the model itself.

This is different from marketing exaggerations where equivalent R of dynamic effects are regularly overstated (not calculated) or the R-value of EPS at a mean temp of 25F gets used (more often by SIP vendors than ICF, though the latter are not immune.) Since ICFs & SIPs are an assembly, not mere insulation it falls outside of the FTC regulations on performance statements, so they can stretch the facts on thermal performance by quite a bit without falling into legal jeapordy.

Posted By Dana1 on 05 Oct 2018 10:16 PM
A mathematical model isn't marketing fluff, nor is it mumbo jumbo. But it also isn't user-friendly or intuitive.

Modeling of mass effects and rigorous vetting the models against both laboratory and real world in-situ testing has been going on at the Oak Ridge National Labs for a few decades now, but the analysis & data would put most people to sleep.

I'm not sure the average person would be able to put the Borst freebie calculator to good use (but some could) but in the end I suspect most won't be making critical design decisions with it, whether accurate or not. Like a lot of thermal modeling (even fairly unsophisticated Manual-J type models) there's a serious garbage-in = garbage out problem, independent of the accuracy or intended use of the model itself.

This is different from marketing exaggerations where equivalent R of dynamic effects are regularly overstated (not calculated) or the R-value of EPS at a mean temp of 25F gets used (more often by SIP vendors than ICF, though the latter are not immune.) Since ICFs & SIPs are an assembly, not mere insulation it falls outside of the FTC regulations on performance statements, so they can stretch the facts on thermal performance by quite a bit without falling into legal jeapordy.

This is why it's called building SCIENCE and not building ART.

Can just about anyone build a house?
Sure.

Can just about anyone carry EVERYTHING in their head to build a house that avoids common mistakes (and sometimes fairly esoteric) mistakes?
Probably not.  And this is why we see structures fail at various points.  Even very solidly built structures.  Because someone missed, or misunderstood something...

But the tools are just that.  Tools.
They're not holy writ.
They're not "The Law".
And like any tool, you have to know how to use it properly or you cause damage to something or someone.

The whole thing seems highly suspect to me. The "whether accurate or not", "garbage in = garbage out", and the long list of major contributing factors that are not even considered or factored in make me think - BS. How necessary is a tool that might work and might not? You wouldn't accept that from any other tool. If it's building SCIENCE - then it's not an exact science, is it? - and there is never a need for anyone to carry everything in their head. All those platitudes don't mean squat to me but if they serve you well, you are welcome to them. Smart home design is comprehensive but it isn't rocket science, as much as some would like to pretend. To me, it is more a matter of the essentials and the non-essentials - and this is a definite non-essential. Marketing is everything, though, and the ability to convince or "sell" something is probably very valuable.

I am pretty confident that Dana or Mojoe have never lived in an ICF house......yet they are experts on them....Dana I do respect you greatly and know you are on another level above us all....

You're correct about that - and I am just as confident that you have never lived in a house where all the insulation is on the outside of the thermal mass.

You earlier stated: "I have a ICF house in Michigan and can easily go 2 months in the spring and 2 months in the fall without using any heat or cooling. In fact we had a mild and consistent summer this year and I ran the AC about 7 days this year. Our high is usually over a 100 F a couple times and all summer it was 93."

My house in central NH performs as well or better than that - if it matters. I didn't feel the need to say so before because it's not a contest. It's not about whose is bigger or better. It's about a sharing of information. I never knocked icf - just the way I was treated because I once suggested a variant method - and look what I got again this time. I'm sure we have more heating and cooling degree days here than you do in Michigan and I never once used my AC this year and I usually don't start burning wood until the beginning of December even though I have plenty of free wood. The normal looking 2 story 3500 sq. ft. save for the large south facing Casement windows coupled with adequate insulation on the exterior of my thermal mass just works. I'm not looking to sell my services or my designs or anything else - but those who do seem to feel threatened.

Thank you Dana. I believe that's a fair assessment of our ICF performance software. Our ICF performance software is certainly not intuitive or easy to use. It is really more of engineering tool that enables us to more accurately and aggressively design HVAC systems and passive solar cooling/heating in ICF buildings...and we PE stamp our engineering designs. We were spefically requested by other building engineering designers to make it publicly available, so we did.

I will also state that I have found our ICF performance software to be very accurate having compared a multitude of actual ICF concrete core temperature time history measurements with the software. The software temperature accuracy was found to be well within the stated accuracy of the thermocouple sensors used for the actual temperature measurements.

How one calculates ICF effective R-value is certainly a complicated matter and should be carefully scrutinized and critiqued. We explained how we calculated ICF effective R-value in great detail in our software instructions and this was further discussed in the aforementioned GBT ICF effective R-value discussion. Our software code is open source so it can be reviewed in detail as well. We didn't attempt to factor improved ICF infiltration performance into the effective R-value calculation and make exaggerated claims like some ICF companies did in the past. Improved infiltration performance can also be achieved using other construction methods.

Mojoe, you appear to be on here to help others and learn, but if don't share what we have done and the results it is all a bunch of talking. I am an engineer for a car company and only build houses for my own enjoyment. You keep claiming that people on here are only here to sell what they do for a living.....

I don't see that at all....Dana for one spends and ungodly amount of time typing things up to help people as does so many others....

If you have a idea build it and show us the results good or bad, we all can learn from it....I have made many mistakes in my life.

I am always trying to learn more and try new things and think most anything can be improved. Not a big believer in resting on one's laurels. There is no need to name names but chances are that anyone with a logo is probably selling something and I'm sure this is a lucrative pond for them to fish in. Several others - for whatever reason - seem to feel the need to keep things pure by discouraging any heresy - not Dana 1 and I'm sure many others but... You've all read what has transpired and will make or already have your own opinions. I have even been accused in a PM of claiming to have come up with the idea of the one sided insulation form although I explicitly said it wasn't my idea earlier in this thread.

Sure, I just can't get enough of the love around here. I'm sure to share more ideas since the others were so well received. After all the kindness, it's the least I can do.

Over the years, I've met many people who call themselves "builders". Several of them not only don't own any tools, but wouldn't know how to use one if they did. They are just another unnecessary middleman that drives up the price of a home. There is a sweet spot that lies in between the arrogant uneducated "builder" and the arrogant over-educated "consultant" "builder". The former tend to be stubborn and are hard to reason with and the latter think they are smarter than and superior to everyone else with their mostly irrelevant formulas and bs verbiage. They use it because they spent their life in school and lack the real world experience. Save them for sizing your high tech HVAC unit because that will factor in things like windows - and it matters.

welcome me back to the ICF legions --after much more searching and cross checking and costings
It looks like ICF will be the way I go
found sensible priced concrete pumping and analized all other options +costings and it looks best all round for my home build.

As long as the price and performance parameters make sense...

Glad you were able to find someplace closer to bring and pump your concrete.

yes after along and involved conversation with a contractor /supplier who has worked in uk with all sorts of SIPS and ICF,s for 20 years +

and asking all sorts of questions and suggesting all sorts of scenarios he convinced me that for our climate the best all round system cost / economy including future running costs
is a 150mm core in 65mm foam ,formers. he talked me out of extra insulation as cost/running benefit would not the there
he just recently changed form NUDURA -cos costings of the product have risen , no quality issues
and now has changed INTEGRASPEC If asked to suggest a system
and having looked at it I agree .
I like all the closure options for the window apertures,even tapered ones which means no wood of any kind .
he has had problems in our mild damp climate with wooden bucks rotting in few years ,which meant a large rework of clients building
I hasten to add not on one of his builds ,but it does show a weakness in including wood next to concrete.
yes they should have used the more expensive "v -buck" in original build --but I have not seen anyone on here even suggesting this could be a problem if going for the cheap option .
a full insulated window/door apertures has to be right way to do it stop any thermal bridging if no other reason
another suggestion he made which makes good sense to me ,although not most economic
If you having second floor then use hollow beam slabs ,as this will then be a good thermal mass and no need for upper floor heating in our climate
I am open to any other system suggestions if you know of better .
I await your observations
also geothermal is now not usually a good choice in such a well insulated home in UK as cost of GSHP compared to air source never works out,
I have friend -who is an architect who is refurbishing a 19th century country home /castle
it has to use radiators due to style and construction --
it has a 19th century dam +hydro which has been upgraded from DC dynamo to ac alternator .so he is using 2 stage air source heat pumps to get 70c and getting most of power from the free hydro +still getting feed in tarrif from government
the cost of destroying the 150 year old gardens and rebuilding to use geo ,was a no go
they even looked ta using the hydro dam volume to use as gshp heat source ----planning said no --you might kill the fish .LOL