I'd say the question of salvageability is whether or not there's enough plastic and foam to reattach siding. Three points:

The odds of being sucked out of a roofless ICF house are far greater than those of being sucked out of a storm cellar.

While it is possible to build a bunker-like house, the aethetic and financial costs far outweigh the benefit. Even in Moore, a tiny minority of houses were hit in '99 and again in '13. See the paths here: http://www.livescience.com/34554-moore-tornadoes-comparison.html

If the ICF house can't be rebuilt, replacement will be costlier.

Your comments about cost and aesthetic constraints against building with ICF are frankly misinformed and sorely out-of-date. IF there is any increase in up-front cost associated with building ICF walls and ceiling deck, those costs will be recovered in 3-5 years with the savings in heat and cooling (50-80% less). My crews have built numerous ICF homes that did not cost any more than comparable homes in the same neighborhood that were stick-built. It totally depends on the builder/contractor. Anyone who has an interest in ICF should NOT be discouraged by a comment such as this.

And by the way, do you have any SCIENTIFIC or empirical data that supports your assertion that a person is more likely to be "sucked out" of an ICF home than a storm cellar? Please – we are dealing with people's lives here...if you don't know what you're talking about, kindly refrain from "throwing something on the wall to see if it sticks!" Survivor interviews in Moore area reported that several of the "storm cellars" were close to losing their steel doors, due to faulty latching mechanisms. No storm safe structure will be effective if it's poorly designed or constructed.

For the record, there are NUMEROUS cases of ICF homes all over the US surviving EF5 tornadoes and Category 5 hurricanes. The Corps of Engineers and FEMA both recognize and cite ICF construction as meeting all requirements for storm safety. We are bidding two schools in Kentucky and two in Texas that are designed entirely with ICF exterior walls and concrete decks, rendering those schools essentially impervious to dangerous storms, and also meeting Homeland Security anti-terrorism requirements. The folks who know what they are doing are choosing ICF as the starting point for safety.

IF there is any increase in up-front cost associated with building ICF walls and ceiling deck, those costs will be recovered in 3-5 years with the savings in heat and cooling (50-80% less)

Uh-oh. Let's try to keep things on the up and up. Things won't go well if you use the industry propaganda here. Fact is that stick-built can be done for less than ICF in terms of energy-efficiency.

ICF has other characteristics that can recommend it above other construction methods, but energy savings isn't quite that much of a slam dunk.

I am currently living in an ICF home that I built two years ago in Oklahoma, and I'm happy to say that you are completely incorrect in this case. I am heating and cooling this 1800 square foot home in an environment where temperatures swing from -10° in winter to +105° in the summer, and my average heating and cooling costs are less than $50 per month. I don't know what the construction costs are like in the Pacific Northwest, but in Oklahoma and the southwest, where I work, stick-built can't approach ICF in terms of energy efficiency of comparable wall facing. And I will completely stand by my 3-5 year cost recovery. I don't know how to be more up and up than that.

bigsumm, I had to follow the link to the Facebook page to see the photos, nothing in your posting at all. Sorry!

I can't imagine that anyone savvy enough to build a house with ICF would not include a windowless ICF safe room – complete with concrete deck and hurricane-proof door, but I suppose there are some folks who are doing it. Keep your property AND your family safe

It seems that we may be partially dealing with a difference in definitions here. The idea of building an entire home that meets FEMA 320 and 361 standards for storm safety, WOULD suggest a complete absence of window openings, and only hurricane-proof doors. But that's not really how anyone would want to do it. Current Corps of Engineers plans for those Kentucky schools I mentioned, for example, utilize ICF for all exterior walls, and also include ICF walled safe areas in the core of the structure. Obviously, the exterior window and door openings (unless they meet hurricane-proof specifications, and some do) render the building envelope vulnerable to flying debris penetration. But a huge advantage to having all the exterior walls in ICF is that they vastly increase the likelihood that interior furnishing, fittings, and contents, will have a higher degree of survivability. Lots of hurricane/tornado survivors are quoted as saying: "we lost everything, but at least we still have our lives." And that's a valid comment – unfortunately when those same survivors face the reality of almost complete loss of personal property, heirlooms, irreplaceable sentimental objects – the warm, fuzzy feelings can be dashed. Build with ICF, add an insulated concrete deck (ala InsulDeck), and include a personal safety room (or area) for the best total solution.

stick-built can't approach ICF in terms of energy efficiency of comparable wall facing

Not exactly sure what "comparable wall facing" refers to, but the facts are that there are any number of stick built sandwiches that will perform higher than ICF, in which case the cost recovery is ZERO. ICF has a large number of features but direct comparison to a stick built on r-value isn't one. Is it possible that you aren't aware of the range of wood frame possibilities?

And, other than labor, what is particularly cheap there in the heartland? Concrete? Steel? Is the Block cheaper?

Update: The ICF shelter that shows the steel rods punching through was a post and beam style ICF building. The rods just happened to punch through 2" of concrete in the beam section. Here are the pics.
https://www.facebook.com/pages/Green-Machine-ICF-Building-Solutions-by-Michael-Summers/331587203573139

Posted By ICFHybrid on 01 Jun 2013 09:02 AM

stick-built can't approach ICF in terms of energy efficiency of comparable wall facing

Not exactly sure what "comparable wall facing" refers to, but the facts are that there are any number of stick built sandwiches that will perform higher than ICF, in which case the cost recovery is ZERO. ICF has a large number of features but direct comparison to a stick built on r-value isn't one. Is it possible that you aren't aware of the range of wood frame possibilities?

And, other than labor, what is particularly cheap there in the heartland? Concrete? Steel? Is the Block cheaper?

If you build a wood frame wall and ICF wall with the same R value, the ICF wall will result in improved energy efficiency in an Oklahoma climate due to the increased mass of the wall.  You may not see much difference up north with the mass wall, but you will the farther south and west you go.

thanks....I'll research.

arkie6,

Couldn't have said it better myself. Except that I would add the much improved building envelope and decreased air penetration, which is what another thread is discussing parallel to this one. Thanks.

bigsumm,

I'm glad you updated that post. I was really wondering about that rebar penetrating six inches of concrete

Posted By bigsumm on 01 Jun 2013 12:03 PM
Update: The ICF shelter that shows the steel rods punching through was a post and beam style ICF building. The rods just happened to punch through 2" of concrete in the beam section. Here are the pics.
https://www.facebook.com/pages/Green-Machine-ICF-Building-Solutions-by-Michael-Summers/331587203573139

That makes more sense now. Something was off when they posted that picture and I knew that those rods could not have punched through 6" of concrete.

I am NOT a fan of the post and beam style of ICF like HercuWall and others. Those systems are never as strong as 6" of monolithic concrete.

Seriously, okicfpro, are you saying that a typical ICF house with wood roof and conventional glass and doors is safer than a storm cellar? Really? You can make it safer, but once you add the costs of concrete roof and impact resistant glass and doors you will NOT recover the costs in 3-5 years. In fact, if you build a structure that looks more like a bunker than a house, you won't ever recover costs because no one will buy it, even in Moore.

Guess what? Those reluctant buyers are right. Here is what Oklahoma City says about the odds of your house getting flattened: "The experts at the National Severe Storms Laboratory have computed that the chance of being struck by a tornado at any given point in Oklahoma is once in about 1,400 years – and you'd have to wait around even longer (around 4,000 years) for a chance of being struck by a significant (F2+) tornado. Whereas, the chances of a Category 1 (75+ mph) hurricane to strike a given point along the gulf or Atlantic coasts is once every 10 years." http://www.abetterlifeokc.com/main/climate/

Yes, one should look at how global warming is changing things... and discover that there are FEWER violent tornadoes in recent years. http://www.wunderground.com/climate/extreme.asp

Your argument for safe rooms is silly. You can build a concrete safe room in a house built of mud and straw. More to the point, storm cellars are the best choice for the 90 percent of Moore homeowners whose houses are still standing.

Your argument for property protection requires facts not yet in evidence. If the choice for the Moore ICF house linked earlier in this thread is stripping the exterior walls to the concrete and jerryrigging siding, or knocking it down and starting over, you haven't protected squat.

If you build a wood frame wall and ICF wall with the same R value, the ICF wall will result in improved energy efficiency in an Oklahoma climate due to the increased mass of the wall

Yeah, I have no problem with that; I'm seeing it right now. But, my point was you could build a proper stick frame with sealing and foam sheathing and beat the ICF even considering the mass effect. The ICF will have other features to recommend it.

The first lesson I learned during my classes in college was that statistics can be manipulated and one can prove or disprove anything they want with statistics. In the end when you are burying your loved one, quoting all the tornado stats and how rare tornadoes are will mean nothing.

Opinions will differ but there is no doubt that a wood framed home is nothing but a house of cards when a powerful EF1+ tornado strikes it. Brick facade homes, CMU homes, post & beam homes, etc. are really no stronger in such events because the walls are hollow in many areas or have very limited or no concrete. Structural monolithic concrete of 6"+ is the bare minimum.

The US Government chose ICF with a solid monolithic wall for the Edwards AFB in California. It looks like a 6" or 8" concrete core.

YouTubeVIDEO

Posted By toddm on 01 Jun 2013 05:42 PM

Your argument for property protection requires facts not yet in evidence. If the choice for the Moore ICF house linked earlier in this thread is stripping the exterior walls to the concrete and jerryrigging siding, or knocking it down and starting over, you haven't protected squat.

Once again you are apparently purposely ignoring the fact that the home took a direct hit from an EF5 tornado and the walls are still standing. While all the wood framed homes were wiped off their foundations. If peoples lives means "squat"  to you, that is your opinion, but human life is not "squat". What an ICF home protects is the occupants of the home, so you protected peoples lives. That is the goal of building structures to withstand such events.

As far "jerryrigging" goes. If the walls are shown to be structurally sound, they can easily strip the remaining foam and install a product like InSoFast which will return the wall to the EPS foam with attachment strips like the original EPS was. The siding can be installed and no "jerryrigging" is taking place.

One thing I think is missing in this discussion is attaining a critical mass.
This does two thing
1- as has been mentioned, it will substantially reduce the flying debris, which is what beat up the pictured ICF house.
2 - more importantly, it you have several consecutive city blocks built of ICF, each house protects its neighbour. Your neighbours still standingICF house will be your primary defence while your own wall will be the secondary line of defence. This won't necessarily give protection from the vacuum effect but will greatly increase the protection from the shear or plow wind effect.

Posted By ICFHybrid on 01 Jun 2013 08:06 PM
Yeah, I have no problem with that; I'm seeing it right now. But, my point was you could build a proper stick frame with sealing and foam sheathing and beat the ICF even considering the mass effect. The ICF will have other features to recommend it.

Only if you continue to believe the nay sayers on this forum and think that the R-value is only the equivalent of R23. The industry continues to say that is not so but the "experts" want to stay with it.

I will repeat what I have said before. My house heat loss calc's where done using R50 as the equivalent for all ICF walls. The heating appliances where sized for that (actually a little lower) Three years now and we have not come close to running low. Last year we had close to a week of -32ºC which is our design temp and it was all good.

ICFHybrid - it seems you will likely be in your house this winter. If we get lucky and have a period of weather close to your design temps, please let us know how often your heating appliance runs. It you have installed for a heat loss based on R23, at design temp the appliance should be running 100% of the time. And yes give it a day to off set "the mass" I'm sure it will only run 50% of the time if indeed you sized to R 23.

I can't say if it hold true for a cooling dominated climate because we don't do air conditioning, but I don't see why not.

Posted By FBBP on 01 Jun 2013 09:41 PM

Only if you continue to believe the nay sayers on this forum and think that the R-value is only the equivalent of R23. The industry continues to say that is not so but the "experts" want to stay with it.

I will repeat what I have said before. My house heat loss calc's where done using R50 as the equivalent for all ICF walls. The heating appliances where sized for that (actually a little lower) Three years now and we have not come close to running low. Last year we had close to a week of -32ºC which is our design temp and it was all good.

All I can say is I'm glad I didn't use R50 for my heating/cooling calculations. My nephew did them using Wrightsoft with 6" ICF wall construction selected in the program. For my one story, 2000 sq ft house w/ crawl space and roof insulation on the underside of the deck, the heat load came out just over 30,000 Btuh with 74F inside, 9F outside. My Daiken heat pump kept the house at 72F when the outdoor temp hovered around -9F to 0F for more than a week. At that temp the heat pump output is only about 20,000 Btuh. It ran constantly. The 10,000+ Btuh deficiency was made up by the normal heat of living, i.e., TV, computer, cooking, bodies, etc., plus a day or two of running the pellet stove at low output.

Heat load calculations generally ignore the heat generated by daily living, which can be a substantial portion of the heat supply in an ICF house, or for that matter any well insulated house. Be sure to factor that into your assessment of how low the apparent heat load is on your ICF house.

In my case daytime solar insolation is a major contributor to the heat supply, not just through the windows but also through the 10" of roof foam insulation. When the day is cloudy in the winter the heat pump runs a lot more hours.

Now, as a contrast let me share something about a stick house. My brother installed a 2 x 6 frame manufactured home on our family farmstead which he owns. This is used as a guest house for his children and their friends. Last week, when the temp was in the 40's there were about 8 people in the house. They had the windows open to cool the place down. This isn't the first time I've seen that. That house is so tight and well insulated that a half-dozen or so adults produce enough heat to keep it warm without running the furnace, even in cool spring and fall weather.