How long go houses last? How much heat and energy would these save over that time? Did you do the calculations to say that they are truly not "green"? These are mostly used for basements, and you should know up in the north the foundation needs to be below the frost line. A carbon intensive digging effort. What do you suggest as an alternative for basement walls? No basement? That may lead to larger houses over all, and it seems everyone wants to live in cardboard box sized houses....if you are a true environmentalist that is.

Ahh, but you are speaking in a general term, which is never an accurate way to determine basically anything.

Constructing above grade with ICFs is prudent if you are building in areas that are subjected to severe weather conditions/high winds/floods. Tornado Alley? Florida? Just two of many areas where sever storms wipe away many structures every year. Just one house rebuild averted more than makes up for the initial carbon load of using ICFs.

So, to sum up, build a bunch of initial carbon heavy ICF houses on the Florida coast, one Cat 3+ storm comes through, you just made your green statement while watching your neighbors hous...kindling piles get trucked away.

LA: should we not be building floating houses for the Florida coast?

Are we all supposed to live in yurts, because a foundation is too "invasive" for the earth? Please give me a break.

You sure can earn a lot of LEED points with this type of building material, which "leeds" me to believe that you are overreacting. Or perhaps LEED isn't green enough either?

http://www.polysteel.com/archengineers.htm

Honestly. Apparantly no materials are good unless they are mostly useless. You can't insluate in humid climates with straw or saw-dust or whatever the new over-hyped pathetic R-value green insulation is in. Foam works better than anything else (although not so much expanded polystyrene). So far, isocyanurate and extruded polystyrene are the best insulation value per inch...

Go as far as this: 6 inch iso-SIP has an R value of over 40. An equivalent wall in straw bales would be over twice the thickness (and this is not including the huge problems of air leekage, window framing and moisture rotting your walls). So that is an average of say 8" more wall thickness, which results in on a 1600sqf house, (25x65') That is Immediately 180sqf more square footage for your house (and area is measure on the outisde walls, not inside) to get the same useable area. Wow, sounds like the foam might take a lead here! If you do a slab floor that is another 180/3 = 60 cubic feet of concrete which is 2 yards! That is a huge difference from a "green" insulation type, this is just the start, we then have a larger roof, foundation etc.

Also, a good house is designed to last 100 years or more, concrete isn't so bad then... Yes it doens't rot into the ground, but wait... that is a benefit when you actually want your house to last.

I think Lloyd Alter is way off base in this article. IFC's are very useful in climates where the frost line must be considered when building. Furthermore, I've seen them used successfully in arid climates (Phoenix) where they do a great job at keeping the cooler temperatures inside the home during the scorchingly hot days. Please note, that the ICF's in that case were above grade, not just used in below grade foundations.

Mr. Alter also seems to imply in his article that homes are built and knocked down all the time. This simply isn't the case. The home my grandmother lives in was built in the very early 1900's. It's still standing there today much as it was then. It would appear to me just looking at homes I see everyday, that the life cycle alluded to in the article is far greater than the author would lead us to believe.

When it comes to the energy savings that these structural members provide year after year in the winter and summer, not to mention that they use less concrete than normal concrete walls, it is clear that they ARE green.

LH: Lloyd specifically said "above grade," so your foundation "point" is misdirected. Maybe take a deep breath first, next time.

How can concrete not be a "green" material? Concrete is made up of 3 things:

* 100% Natural Earth (also known as rock)
* Gaia-Produced Portland Cement
* Organic Water

--
editor note: "the manufacturing of concrete is responsible for up to 7-10% of all CO2 emissions worldwide"

http://www.worldchanging.com/archives/003151.html

Yurts are an extremely invasive home technology, and not particularly green.

They KILL every living thing that was once gloriously soaking up the bountiful sun UNDERNEATH them.

BAN YURTS!

The manufacture of ANYTHING produces CO2.

Manufacturing offspring produces a net gain in C02 emissions. That's not the point.

The author claimed that concrete, a product consisting of all-natural ingredients, is "not particularly green" when in fact, it is 100% green.

It would be like saying that "trees are not particularly green" just because people carry them around in CO2-producing logging trucks.

it's have low level of fire resistens. Need to use mortar about 35 mm. and mesch for it.

Lloyd, that was a silly comment: floating houses. I'm not talking about building in places where it STAYS flooded. I'm talking about places which get hit with high/catastrophic winds. A flood will still damage an ICF house, but not in a structural fashion. More cosmetic in nature and more easily repaired. Tornado alley doesn't see much flooding now, does it?.

Looks like everyone who has responded also thinks you are a bit off-base here. No biggie, just reality.

I like constraction systems witch uses polysterene. But this sys has a low level of fire resistens. Need to use more 35 mm of mortar.

The energy that goes into making mortar is not insignificant, so if you build a concrete structure you should plan it to last, which seems less and less likely as land gets more valuable and tear-downs of perfectly good houses become more common.

Perhaps something in a building code that requires a concrete new builder to guarantee that he won't tear-down for a given number of years (40-60?) and which is binding upon all subsequent purchasers, waivable on paying some kind of carbon mitigation/waste fee.

Concrete overenthusiasm has killed off civilizations. In central America, it took three buckets of wood to make one bucket of mortar. Maya denuded their forests to build their magnificent temples, and then drought put the kibosh on their advanced economy.

But if its designed lovingly, to last, it's great. Look at the Pantheon!

while i tend to agree with lloyd here in general, this whole issue is very messy when you try to parse out the eco-economics of the materials. what is ironic here is that bill mcdonough's first endorsed building materials is the 'green sandwich'. essentially a modified version of the ICF.

concrete is extremely energy intensive to produce, one of the largest single co2 materials you can aqcuire. yes, the lifespan and post-life inertness of the material are very green, but calling it 100% green is also way off base. it may be the greenest and most responsible option available, but definitely not "100% green". the above analogy is false. growing wood absorbs carbon which compensates for the co2 released in processing it into lumber. there's no similarity in mining and crushing rocks. it's a pure net loss.

the problem with SIPs is that they are a mess of materials that are inseperable, non-recycleable, and actually fairly toxic (glues and foams) at the end of their life. osb is an end-of-life product that can be nothing but landfilled (no burning or mulching). SIPs are however, very energy efficient.

Regarding SIPS.

Sips built with isocyanurate foam, which has an R value of around 7, do not use glues, and they foam and glue can be delaminated with not much effort, with knives or the like.

and OSB can be composted when mulched wiith mushrooms, as mushrooms are able to break down almost the most toxic stuff (and the glue in OSB is not that toxic).

Anyways, SIPS i think are likely the best option, as you get a VERY air tight house, which is quite important for high heating/cooling areas.

Some interesting points starting with Lloyd's and all the critiques afterwards.

I agee with some of the critiques that it is not fair to say it isn't "green" but it usually gets an unquestioned free ride and Lloyd is willing to question the accepted--is it "green" enough? The energy saved in some climates would be more than in others. Is the life span longer? I know the concrete will last virtually forever but what about degrdation of the foam? The foam is also an easy path for termites and to eliminate that path I believe would require thermal bridging. When you stated "serious architectural overkill" I assume you meant structural overkill but as someone else pointed out, not necessarily in a hurricane zone and maybe not in San Francisco either (seisemic zone). A couple of other points not previously made: It requires a larger footprint to yield the same usable space because the walls have to be so thick using more materials for footings, roofing, etc. If sheetrock is being mounted directly (as it is designed to be with imbedded plastic screw anchoring) the electrician will be routing out foam for wiring conduit creating more thermal bridges.

Given a sandwich-style ICF like the one Lloyd used to illustrate this article, his points have much more strength. But some other ICFs, like the Insulock blocks, are primarily foam, with cores for pouring concrete and adding re-steel. Using these helps to significantly reduce the amount of concrete needed versus either a sandwich style ICF or a traditional concrete basement wall. An 8" Insulock wall also offers R-38 insulation, versus R-22 for an 8" Eco-Block with 4" concrete. But either one is vastly better than an uninsulated 8" concrete foundation wall.

For above grade construction, it is not even necessary to fill all the cores, enabling further savings in material and embodied energy.

I agree that there are many cases where using ICFs above grade is not the most efficient use of resources. But some other comments to this have already pointed out cases where someone might reasonably choose to use that approach. To those others, let me add a case where a building was being built by a crew with only limited skills. Fewer kinds of materials going into a building also means fewer supply trucks making deliveries to the site.

Lloyd Alter hit the mark on this one. He's absolutely correct.

ICFs are two high embodied carbon and embodied energy products slapped together and painted with greenwash.

ICFs should have long ago been the standard for basement walls, not an upgrade.

For those interested in doing one for the planet, there are far better options for highly green and sustainable walls above grade. As for below grade, if it means not having a basement, then so be it.

OK, Mr. Greener-than-thou ... I say we get rid of basements. Everything down there gets wet and moldy. It's really hard to play ping pong unless you have really high ceilings. Also, there's the radon gas.

The solution? Just stick everything in your garage. It's above ground, and the mechanical door opener doesn't work anymore, so why park the car in there?

There are ways to use a lot less concrete for house foundations. Ted Owens shows how in his book/DVD (just google him). It's called "rubble trench foundation". It still uses concrete, but a lot less, and it meets code.

mushrooms to mulch OSB? i hope that can be true someday and i'd love to hear more (links?). right now, it sounds like an overly hopeful concept. i recently toured a material disposal business... the largest in the tri-state area, the one responsible for sifting through WTC material... they work with steel, aluminum, lumber, plastics, etc and they said OSB is end-of-life. they cannot do anything but landfill it because of, yes, toxic, glues in the material. SIPs are loaded with glue. and burning (as homes often do) is possibly the worst case scenerio.

further, there are good arguments that they create an overly sealed home and always require mechanical systems to facilitate air exchange. that means energy use, maintenence, indoor air quality concerns, and safety issues with CO. it might not be the wisest choice to live in an air-tight envelope. i'm not rallying against SIPs, but it's good to consider the bad with the good. they are not necessarily as green as the companies producing them want you to think.

All the acronyms get confusing, but SIP is not the same as ICF. No glues are used in ICFs. When an ICF is exposed to flame, it will burn at the point of contact, but the flames do not spread, and they do not produce any toxic off gasses (though, like all smoke, its not good to breath it).

I keep hearing that there are many better solutions to green construction than ICF, but what are they? I am not familiar with anything you can take to a housing developer or a commercial construction company, and they can start using now, with current plan, crews and tools, that will reduce heating and cooling costs of the building by 40%.

ICF Construction isn't replacing strawbale houses, it is replacing wood houses with fiberglass insulation. Can you seriously say fiberglass is greener than concrete or even EPS? Fiberglass, like asbestos causes cancer and lung problems!

ICF Construction is replacing pour-in-place concrete. Wooden (trees from forests) forms are built for the walls, treated with diesel (toxic) so the concrete does not stick. After the concrete is dry the forms are torn down and hopefully re-used a few times before their toxic remains are land-filled. And the concrete walls- still have no insulation or energy savings. Is that better than ICF?

Lloyd calls it green-washing- I call ICF a real life solution. We don’t have time for fantasies about everyone living in rammed earth Hobbit pods and skyscrapers disappearing because we are beyond the consumer era.

In just a few years we will have reached our maximum greenhouse gas emissions that will create the 2 degree climate change that will change life as we know it on the planet. Building operations account for 48% of those emissions- lets use what we have, like ICFs, to cut that number in half, and then added technologies to take it to zero!

This article is off-base.

I live in a hurricane area.

I NEED concrete. The only structures which survived Katrina were concrete and domes. You can look it up.

SIPs will not cut it here. Although many people use them out of ignorance or economy.

When you really plan to build your own home, you design it to last as long as you can. Homes are the most expensive things that most of us buy.

All materials have pluses and minuses. In terms of energy, cost, length of use everything.

There is no way to predict what the next person who puchases you home will do with/ to it. They may live in it. They may tear it down. If it is well designed and constructed, they may live in it.

There isn't any one answer that will satisfy all people. Some like yurts, others do not. It is fine. Are you a nomadic herdsman living in Mongolia? A yurt may be the best choice for you. Do you live in a tornado area? ICFs may be the best for you... How much money have you got? This factor may decide alot of things for you.

The url for Philip's article on green options is broken. Here is the updated link
http://greenbuildingelements.com/2007/04/02/insulated-concrete-forms/

I am getting ready to build a house out in the country, and I find some of your suggestions that ICF's are not as "green" as you would like them to be ludricious.

ICF's produce savings in CO2 emissions by my NOT running the HVAC systems all throughout the year because of the thermal mass effect of all the concrete behind the walls. I fire up my AC for maybe two hours and the house stays a comfortable and stable temperature for the rest of the day. This includes summer and winter climes. ICF's are 10 times stronger than brick or wood-clad houses, which is a great benefit if you live in Tornado Alley (which I do), or if you live near the coast where a Cat 3, or Cat 4 hurricane will produce a monsterous carbon imprint when your built house begins rotting in a landfill after its blown away. Another thing which you also fail to mention, is that with changing weather patterns - grass and wildfires are a real threat to most houses. Add a brick or stucco facade and a steel roof to your ICF house and you have a virtually fireproof house, which WILL not add to the current pollution in the air when your house turns into a matchstick. Another added asset is also the fact that I don't have to worry about structural damage done to my house by termite infiltration, or damage done by carpenter ants. This includes NOT having to use invasive chemcals to kill or control the termites, which could get into the water table. Also add in that ICF are easier to work with when it comes to radon gas abatement should your house experience that kind of problem.

Some of the research on ICF and concrete houses shows a lifecycle of 100 years. Since stick-built houses have lower lifecycles (even more so in termite infested environments, and higher humidity climes where wood rot is more apparent.) - stick-built houses show twice or three times the carbon imprint as a result of old houses being demolished (and currently, there is nearly 0 recycling done for demolished houses - it's a trip straight to the landfill).

Also remember that with a 100 year lifecycle, I can lower my carbon imprint by installing rainwater catchment systems to water all the trees on my property that I intend to plant.

There is a front end load for ICF's in the beginning (expanded stryofoam blocks and plastic holders for the rebar), but the long-term effects of using ICFs causes these kind of buildings to have a significantly reduced carbon "footprint" for the long-term lifecycle of the house.

I think this could be an extremely green way of building, especially if geopolymer cement were used to produce the concrete. Standard cements release a great deal of carbon emissions during production, geopolymer cements release much less.

There is little building waste (which often ends up in landfills) when building by this method.

The obvious energy savings you gain from the insulation.

The house will last a long time so you save the carbon emissions associated with building a replacement.