after much deliberation and comparing all insulation systems and cross checking with prefered way to build zero energy homes then sips definately win hands down . ICF wall would still need extra insulation to get to required spec--so why not do it with the sips which is easier and quicker with no requirement for specialised equipment . my only reason to use ICF would be in a basement+sips above ground, and only because the ground loads are great -I discounted below ground SIPS as they still really need same water proofing that concrete does to be sure +if it fails could then be a real problem and at 200mm min wall thickness for concrete or blocks + thicker for sips.then concrete seems the right choice for long term peace of mind . your comments welcomed with reasoning behind them

We are building a house in the Florida Keys and were going to use ICF. The costs, due to many factors, are very high. I was told that ICF, where the difference in the temperature is only 30 degrees (inside vs. outside), is an expensive product and may not be the way to go. We are stuck on how to proceed. Follow along at: www.ourhouseinthekeys.com

Not here to cut down SIPS, not my specialty and very limited knowledge in them

In regards to ICF. First and foremost is the strength factor of a reinforced concrete wall, nothing beats it, not SIPS, not a framed wall, nothing.

Now, put down the pen and paper and lets look at reality, proven reality, concrete wall with 2 layers of EPS on both sides, typical standard ICF is 'Rated' at R22, some newer R30, and as I've seen you can keep adding layers to get whatever R denomination you want. In my opinion, and this only an opinion, it doesn't matter. The R value is based on what some lab has determined the value of the foam is worth, add something for concrete, something for facade and something for drywall (yes, they all have an R value) and the typical ICF assembly wall is sitting somewhere around R24 to R25

In reality lets look at your climate, I live in Ontario (The claimed birthplace of ICF for North America) and my energy bill is typically $4800 yr for electric and NG, this includes standard 80,000 BTU furnace, pool heater which we keep at 88f from May to Sept, bbq, stove for NG and AC for electric, plus lights, pool pump 24/7 May to Sept, 3 fridges, etc etc etc. My house 2200 sq ft was built in 1963 and has pretty much no insulation in the walls, attic I redid 4 years ago

Now ICF house, similar size, similar features and use as my house, electric and gas roughly $1500 year, huge savings. take out pool heater and pump and not many people have 3 fridges, 1 yes, maybe 2, that bill would be $ 500.00 year - that's cheap

Anyone got specs on a SIPS house with similar use?

So I get the net zero idea, but were talking $ 500.00 year for utilities. you have to pay something

So ICF gives you as we all know

Concrete walls - strongest out there
Better safety factor during a fire
Better safety factor during a natural disaster
Energy savings is negligible between the different 'energy efficient systems' these days, minor in nature - nothing to write home about - prove me wrong

To me life safety beats out everything

Thanks for reading

Chris Johnson
Retired ICF contractor

Both ICF and SIPs have advantages and disadvantages depending on the location. Both can be accomplished DIY for a fraction of hired cost if one takes the time to get the training and is reasonably comfortable/competent with this. SIPs go up very fast and we prefer the steel skinned SIPs over the OSB SIPs to reduce the risk of delamination, bug/rodent infestation, rot, etc. ICF performance truly excels in diurnal climates where you can get three times the ICF conventional R-value performance by taking advantage of the thermal mass effect (we have free ICF performance software on our website to evaluate this). If you have a termite issue, special care must be taken with both to avoid disaster.

I read all and can see why you might think that the ICF is better
on strength ,but that argument is flawed,if money is part of the equation --just use a thicker SIPS --in uk we use up too 9"or even 12" for full passiv house -normal minimum is about 6"
now the idea that the thermal mass of the ICf is a help is just wrong -if you insulate it both sides then it will not change in temp - so had no effect really .If it does make a difference then insulation is crap--so to say just use more insulation on inside of an ICF to lift "r" ,then you might as well just use a thicker SIPs to start with which will give the extra structural strength at same time .It s a simple thing ,more insulation will keep house hotter or colder.which ever you want and when coupled with heat recovery ventilation ,which is a must because both types of houses should be air tight , so in a hot climate the air con loads will be much less if inside does not get heated up by lack of insulation . with heat recovery ventilation system you will also be dropping your air con load again.

So ICF gives you as we all know

Concrete walls - strongest out there
Better safety factor during a fire
Better safety factor during a natural disaster
Energy savings is negligible between the different 'energy efficient systems' these days, minor in nature - nothing to write home about - prove me wrong

To me life safety beats out everything

you forgot bullet proof!!, maybe important in US. LOL
the others are covered by insurance and a decent fire detection system .--house interiors will still burn unless you are living in a bunker --to increase fire protection use steel or cement board sips.although i really think you will be either dead from smoke or out of there before its a problem ,your ICF blocks will still burn +make lots of killer fumes.

heres a link to scottish company --i have no relationship with them -check out the MVHR section --looks like a great and simple way to get upto 97%heat recovery using this ventilation system ,also very simple to fit --https://www.ecoenvelope.co.uk/.
will be what i use in next project no matter what main build system

right, usually the first thing to burn in a fire are the contents and furnishings of the home so you will be long dead from the toxic fumes and smoke from those before the structure becomes involved.

Don't expect a rational debate here. This is a partisan forum sponsored and largely haunted by corporate interests, their lackeys, and those that have personal financial stakes. Sadly, it is not the place for the free exchange of ideas that may lead to better methods of home building.

Their response is "This is an ICF forum." Go somewhere else with your contrary ideas. You got a better response than I did with my heretical proposal [not that I was the first] to restrict the insulation to the outside of the concrete in order to take advantage of the thermal mass because isolating it in a sandwich seems silly in most cases - except for those selling the icf forms.

In what I call the, "It won't be a good idea until WE think of it", I see many icf manufacturers now offering one sided insulation forms.

SIPS are good, too, and continue to evolve as well. We first used them back in the 1980's in combination with high thermal mass passive solar post and beam homes and HRVs. Good link.

Ah. Someone trying to start a flame war over a construction method.

Now I've seen it all.

Can someone show us on the doll where the evil ICF contractor touched you?

*sigh*

See what I mean?

Sciott....yu need to go on-line and find someone to come down there and build an ICF house. Even if you have to pay to put them up in a motel for a week or two. IMO....it's worth it where you are are..............

I liked the idea of ICF for a couple of old guys me and brother,so we could build at our own pace and no worries over rain damaging half built house,but costs of concrete pumping boom ,racking rental,rebar benders ,concrete vibrating poker etc--none local makes it not the easy/cheap solution it sounds for self build - --but then you dig into it deeper --ICF is best solution for a basement ,but after that the "u" values don,t stack up without adding more insulation internally .
a sip frame all you need is a chalk line and spirit level + framing nail gun or screw drivers
If i was going to go down contractor route a sips would be up+water tight in 3 days or less with a 4 man team from slab -- with no basement

By us, a boom truck is only a couple hundred dollars for the couple of hours need to pour the concrete. You can buy braces and then sell them for what you paid for them. Same with vibrators. So I would say both ICF and SIPs are very DIY friendly if one takes the time to research and get trained before jumping into it.

Don’t discount the ICF thermal mass effect either. Our ICF behaves like R60 in our Summer diurnal southern Oregon climate totally eliminating any need for AC even during our 110F days. In the Winter it behaves close to its conventional R23 R-value but our Winters are relatively mild. These days you can buy ICF with whatever insulation R-value you want and have it where you want it (equally sandwiched or more toward the exterior or interior side). So you have many options and you first have to carefully consider the location and climate before making a decision.

Posted By mojoe on 03 Oct 2018 02:02 AM
See what I mean?

Unfortunately for your argument, I'm neither an ICF contractor, nor one of their lackeys.
I have no problem use any construction technique that works.

What I have a problem with is someone coming in here and simply crapping on something because they don't like or don't understand it.

But please, go on with the Great ICF Conspiracy...

Posted By sailawayrb on 03 Oct 2018 04:33 PM
By us, a boom truck is only a couple hundred dollars for the couple of hours need to pour the concrete. You can buy braces and then sell them for what you paid for them. Same with vibrators. So I would say both ICF and SIPs are very DIY friendly if one takes the time to research and get trained before jumping into it.

Don’t discount the ICF thermal mass effect either. Our ICF behaves like R60 in our Summer diurnal southern Oregon climate totally eliminating any need for AC even during our 110F days. In the Winter it behaves close to its conventional R23 R-value but our Winters are relatively mild. These days you can buy ICF with whatever insulation R-value you want and have it where you want it (equally sandwiched or more toward the exterior or interior side). So you have many options and you first have to carefully consider the location and climate before making a decision.

John is, as his name suggests, in Scotland.

This is one of those "location, location, location" things.  Like the gentleman building his house in the Florida Keys.

Location can drastically multiply material, equipment and labor costs.
So, depending on those multiples, certain types of construction may, incidentally, wind up FAR more economical.
If you're in hailing distance of a metropolitan area, having access to concrete and concrete pumping equipment is generally easier and more economical than being at the ass end of a dirt road in Bumblefsck, Idaho (population 15 and shrinking) where the nearest concrete mill is a 2 hour drive away.


As with any construction technique, use what makes sense for your area, your budget and your preferences.

thats the problem -pumping boom is 100+miles away and £600 a day --and thats a 5hr day --concrete is basically 2hrs+ each for truck as well maybe 3hrs with turn round time --so hire costs of these things add a big chunk --in Uk concrete is around £90-120 per cubic metre and only 6 cube per truck
my guess for where I am is the concrete and equip will work out at around £180 -£200per cube where as in london it would be £120 per cube -due to competition form suppliers--not finished computing yet as with basement ICF is the way --
ICF block suppliers here will rent the support racking --£20 per week +transport ,thats OK--will post when final costs are nailed down

thermal mass I do discount it as it is insulated from the interior of the building by formers . thats not to say i would not insulate under concrete floor --then that a thermal mass --but the walls --NO-unless your insulation is so crap it allows heat to get to the middle it will be of no value other than the heat it can suck from the foundation slab +then its sealed in by insulation both sides. .
To me ICF is a quick and easy way to build a concrete structure without days joiner work to build wooden shuttering ,which you then throw away ,I might even consider precast concrete slabs for basement --will be checking those for pricing as well--the water proofing appears to be same cost no matter what system you use .

Scotty, glad you are finally researching and learning something. Hope you have success with your project. Sounds like ICF doesn't work for you because of the cost of supplies to your location. Knocking a product for your reasons without initially stating them isn't cool and from your other posts, I think my tag line fits you well.

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.

Again good luck....

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. You first have to carefully consider the location and climate when accessing ICF performance and there is free software on our website to do that. Using ICF in our Summer climate with a 60ish effective R-value eliminates needing AC altogether. One can certainly get there with SIPs or well-insulated double/single 2x wood wall designs too, but making ignorant or blatantly false statements about ICF isn’t helpful.

I value empirical evidence over theoretical. You probably fit into all 3 of the above aforementioned categories. Nothing in life is free. Your software isn't free - it's bait. You want to nit-pick about the irrelevant while ignoring the obvious and claiming to be the sole possesser of the "truth" because of some "software". Does this software have any independent 3rd party approvals or verifications or is it just something you made up? What about windows with an R value of 4? Oh, that's right, you suggested having no windows and using video cameras to project images of the outside - and my statements are ignorant? - at least they aren't self-serving.

Thermal mass is what smooths out those extremes of temperature and insulating yourself from it after spending so much on it is just silly - in most cases.