Why Build an ICF House

[rgood]

I think that's a good question - And obviously there are lots of ICF houses with windows on the S. side - So, Why build an ICF house?

1. I used to live in Germany and almost all of the houses are concrete there - And many of the people there now live in their grandparent's house. For many people a house is also an investment, so why not invest in something that will last that you can either sell or give to your kids or grandkids. If you go to Ireland you'll see all kinds of stone houses that are 400 years old. The obvious rebuttal to that is "How long are you going to live?" But still, it'd be nice if Grandpa left something for somebody.

2. ICF houses greatly reduce jet noise, road noise, train noise etc - May not be an issue, but might be depending where you live.

3. Do ICF houses cost that much more? Most web sites say 10% more - My builder says 5% more - I'll let you know.

4. Insurance cost is reduced.

5. In a tornado, the roof normally flies off and then the walls fall in. If hurricane straps are used and a hip roof is used, your roof might stay on - If it doesn't stay on, all you have to replace is the roof. Additionally often times tornado damage and deaths are caused by a flying board or piece of metal - Which will go right through siding and sheet rock, but won't go through an ICF house.

6. Even with windows in the house, your heating/cooling bills are greatly reduced, Because the concrete draws from the heat or the coolness of the ground.


What are your thoughts?

 

[slowzuki]

Number 6 isn't true, it is just well insulated. The extra mass in the outside wall slows swings only slightly, and its not connected to the ground well enough for the ground to play a role.

 

[rgood]

Slowzuki - I checked this out and you are right - It does not have to do with Ground mass, yet it is correct that most studies show ICF houses to be 20% more energy efficient. Thanks for the feedback.

 

[BruceWard]

I researched ICF a few years ago. I bid out the same house plan for 2x6 framing, SIP and ICF. ICF was over twice the price of 2x6 or SIP. I decided upon SIP and am currently building. I would love to live a concrete house but at $100K for exterior walls vs $40K for SIP it did not make sense.

 

[JB4310]

I think the concept is great, they just have not caught on, and that's been the case now for 30 years, 20 years ago they had not caught on. 10 years ago they had not caught on. So it looks like they never will.

It's got to be the cost or else we would see more of them. If it was only 5-10 % and the house would look the same, people would be building them just for the energy saving factor.

No reason a wood framed house can't be passed on for generations, My first house was built in 1832 !!

JB

 

[Mounted Madness]

We had our house built in 2007, moving in Jan 2008. We'd looked very seriously at ICF for the whole build, rather then the standard concrete foundation and stud walls. With the increasing frequency of high winds and even tornados, I figured concrete would be the way to go.

The lot we wanted was owned by the builder, so it was that builders price quote that we had to follow. Their standard build was the usual concrete, studded and insulated, with standard frame construction above grade. Our last house had ICF foundation, so we had the builder quote that...$8,000 more for the foundation.

The basement is warmer and quieter and less prone to humidity we get here in the summer. Looking back 4 years ago, and if we'd had the extra $8,000 for the main floor, it would be an option I would go for without hesitation.:thumbsup:

The cost difference would have been about 6-7% more by my estimate from the standard build costs.

 

[rgood]

I just googled "Cost of ICF house" Every one that comes up says 2 to 10% more except for one that said 20% more.

Maybe there are some "regional cost differences?"

I think alot of the difference is in the Labor costs.

The builder I'm working with only builds ICF houses - I think that makes a difference too.

 

[czechsonofagun]

If the market was geared towards brick, stone, concrete building, the cost would drop too.

In my country it is the same as Germany, buildings from wood are just temporary or summer cabins and such. And we don't have the America's crazy weather like tornadoes - strong winds may damage the roof and break windows but they will not make a pile of rubble from a house. Also thing to consider is fire - wood house means you are living in a pile of kindlings - if you ever saw stick build house burn, you know what I mean.

 

[JB4310]

I just googled "Cost of ICF house" Every one that comes up says 2 to 10% more except for one that said 20% more.

Maybe there are some "regional cost differences?"

I think alot of the difference is in the Labor costs.

The builder I'm working with only builds ICF houses - I think that makes a difference too.

I don't get it, if it's even 10% higher that would not be enough to turn away people who are building their dream home, especially if it is a better type of construction (which I believe it is).

Sure a profit builder is not interested in paying more for anything, but an American consumer.....

Are these numbers just for the cost of materials? cause everyone working on the house, from plumbers and electricians are going to face things they are not use to, which is going to cost more.

I've seen ICFs at trade shows 25 years ago, never seen a house built with them though. I would like to build a shop with them some day.

I don't even see the need for the insulation, those forms are the expensive part, why not just conventional forming and a styro board put over the out side wall.

Isn't 8-10 inches of concrete a pretty good insulator? Maybe not since there is not alot of air space in there?

JB.

 

[dmccarty]

An ICF house costs more for very little benefit when we built. At that time concrete was very expensive, was in short supply, and was being rationed to builders. Using concrete for ICFs would have been very expensive. I think we paid $90ish per yard and that was cheap. Other places were charging $100-110 per yard. The concrete cost for ICF in our house would have been around $4,000. Then you have the cost of the ICFs, rebar, and labor.

I seriously started looking at ICF's back at least in the early 90s. Contractors are very conservative in what they do and for very good reasons. Not many build with ICFs so you either have to find a builder with experience or deal with an inexperienced builder. Which is going to increase your costs and risks.

From an energy efficient perspective a stick built house can easily meet or exceed an ICF house. Just not that hard to do for less money.

An ICF house could/should be better in a tornado but the odds of a tornado hitting my house is basically zero. I looked at tornado data for my state and I think my county has only had 1-2 tornado very few decades. The chance of my house getting hit is pretty small.

Another item we wanted in the house was a fire sprinkler system. The old code made it all but impossible to put in a fire suppression system however the code changed just before we built. I asked the insurance company how much my house insurance premium would decrease if we had a fire sprinkler system in the house. It was something like $25-50. A year. This told me that the odds of my house burning down was also close to zero.

For hurricanes, the ICF house has an advantage if the windows and doors can be protected from debris. If the windows and doors fail, and the wind gets into the house, I am not sure how little hurricane clips are going to hold down the roof in big wind. Our house is well inland but hurricanes can and have had hit our area. We have hurricane clips. I think our house would survive window/door failure because the winds would barely be hurricane strength. Down on the coast would be a far different story.

Our house has R25 2x6 walls and is very quiet. It would be even quieter and more energy efficient if we had not put in lots of big windows. The windows was also a reason to not use ICFs. Why build this expensive exterior wall and then poke holes in it?

We found a builder we liked, was a PE, knew his stuff, could be trusted and who became our friend. How many people can make that statement about their builder? He was very willing to build with ICF but it would be a learning experience for him and a risk for me. Simply not worth the risk for little to no gain that I could see.

When it came time to spend money I just could not justify the extra cost, and in our case, risk, to use ICFs.

If I lived in a place where very strong hurricane winds could hit, I would seriously think about ICFs.

Later,
Dan