I live in Sioux City, Iowa, home of Lite-Form Technologies, actually it is across the Missouri River in South Sioux City, NE.  I went to your local home show yesterday and Lite-Form was there demonstrating/showing off their products.  My brother recently built an ICF home and found out later there were many hollow spots using the traditional product.  Representatives at the home show showed me their new product, Flexx Block, which they said will stand up to rigorous vibrating to ensure that concrete gets into all areas.  They showed me how the plastic cross ties had gotten much stronger.  The salesman seemed very knowledgeable and really convinced me to go the ICF route, which I've wanted to with our projected build date not until spring 2008.  The one big fear has always been not getting concrete into all the areas.  Is there anything you guys can tell me that would allay my fears?  Do problems with hollow spots rest mainly with inexperience on the part of the installer, the inherent weakness, if any, of the ICF form, or the cement being too dry and not being able to flow adequately?  I plan on going with a concrete floor utilizing radiant heating and geo thermo heating as well, with the ICF extending all the way up to the roof.  It's a year away from build date but I'm already getting excited at the prospect of an energy efficient home like an ICF.  Thanks very much for your help! 

" Do problems with hollow spots rest mainly with inexperience on the part of the installer, the inherent weakness, if any, of the ICF form, or the cement being too dry and not being able to flow adequately?"

Yes to all three, and they're all related. Higher slump, more fluid, better infill properties, ...but more form pressure. Stornger form, lower slump, better vibration properties, but again, inexperience can cause pockets or too much vibration can cause block failure.

Having a block blow out is not a problem, it's how all things related are done in the rest of the installation!

Let's get this out their, The ONLY way to get concrete in ALL areas of any form is to internally consolidate it!
I don't care if it's an icf or any other form concrete needs to be vibrated.
I see a lot of contractors afraid of the vibrator and pour a 6" or even a 8" slump mix and think this will flow.
I ask you this, why bring up the stress on the forms having a watered down mix to bring up the flow?
If you pour a thicker mix a 4" or 5" with large stone and vibrate it you are only stressing the form in a small area for a small amount of time.
All forms will hold concrete if installed correctly (some will take more work than others) but all need to be vibrated INTERNALY.
Let us just look at the first inch at the bottom of the form , this is the most important part of the wall (the cold joint).
When we pour all the rebar, ties, and form hold a lot of the Portland (cream) sand and fines that fill all the voids on it way down.
So the rock hits the bottom (a cold joint) and has more of the same fall on top of it until its full.
You can not see in the form so you can not see this but you know its happening.
now if we introduce vibration in the mix the cream changes in to liquid and moves down to fill the voids.
You can see this when pull the head of the vibrator out and the concrete drops down in the form ( where did it go) it filled the voids and drop all of the larger rock tighter together. (good concrete)
We all want good concrete and the only way to get it is to ITERNALY VIBRATE !
If you don't think I am right just cut out the foam at the 1" mark at the bottom of the form and look at the cold joint. Don't worry you can use some foam in a can and glue it back in. If you see gravel and voids on the bottom you got a wall siting on ball bearings just waiting the move and rebar with void around it not able to hold it.
Now if this is under grade (on the footer) and water gets in(and it will) the rebar will rust and fail to hold back back fill and water pushing in.(not good)
Find a good contractor that will use a form that recommends that you INTERNALY VIBRATE the concrete in their forms and you will have GOOD WALL.
I hope this will help you with your fear with using an icf product on your new home.
Their is no bad information, just miss informed decisions.
P.S. all of you that wish to argue with this look it up . http://www.arit.com/voidspace.htm
Good luck with your build.
Regards ,
Scott

I agree with Scott on the consolidation issue! I would like to add my 50 cents worth on this issue to make sure there is a very clear understanding on consolidation.
Here we go the first part of this issue is an experienced contractor, and because all of the walls out on the market today have some differences it is important that the contractor is experienced with the wall that will be used.
Should you choose a less experienced contractor it is also important that they know how to use a consolidation device, and from here on in lets refer to that device as a vibrator.
Unfortunatley we have a whole lot of people that get a new tool and do not know how to use it properly, for example if you vibrate a wall to much it will move all of the aggregate to the bottom of the wall reducing the strength of the wall at the top. Concrete is designed with strength in mind, the aggregate is what gives it the majority of its strength the cream as it is called is the binder. Over vibrating the wall will also increase the pressure of the fluid density in the concrete creating extreme pressure on the foam in the wall system which in turn will cause a blow out.
For most wall systems the manufacturer will recommend the amount of vibration or consolidation to use, and it is pretty much the same or close on all of the systems out there. The real key to proper consolidation is that you use short burst switching the vibrator on and off, the concrete will consolidate very rapidly if the correct slump is being placed in the wall, and infact less than a second of vibration at any given spot should be sufficient.
Slump this is very important most wall systems will recommend a 5" to 6" slump no more and no less. Do not depend on the truck driver to know what slump he has in his truck although his gage will give him an idea of what slump is I have personal experience that the gage can be wrong. The best thing to do is to test the slump, and this should be done at the end of the hose on the pumper truck not at the mix truck. Here is why I say this, depending on the tempature and humidty in the air slump will change about 1" as it goes through the pumper system on average. With that said if you do check at the mix truck you will have to take that into consideration. I will give you an example; If the mix truck arrives and the slump is at 4" and your goal is to be at 5" going into the wall you will need to change the slump at the mix truck to a 6". To change slump to a 6" you will have to determine how much concrete is in the truck, and lets say it is 10 yds. that means the slump would have to be changed by 2" inorder to achive the correct slump at the wall. To change slump the rule of thumb is 1 gal. of water to 1 yd. of concrete will change slump by 1" in this case you would have to add 2 gal. of water per yd or 20 gal. inorder to achive the correct slump at the wall.
It appears from your post that you are the potential home owner and not the contractor who will be building the walls, but this should give you some knowledge and questions to ask your contractor so you get some one who knows what they are doing.
I have heard most of the sales pitches out there in regards to the variuos wall systems and the question to be asked when some one claims that there wall is able to be vibratated till h_ _ _ freezes over is this do you gaurantee that I will have no blow outs, not a one will do this, the next question to ask the sales person is what happens to concrete if it is consolidated to much most can not answer that question, so go to the ready mix company in your area and ask them what will happen to concrete if it is over vibrated, the answer will be it reduces the walls strength.
The leason here is two fold make sure the contractor you choose knows their stuff, and ICF walls built correctly are the best way to go.

Interesting... I always thought that vibrating from the outside of the walls on the nailers that run all the way through to the other side would transfer the vibration to the interior.

That also works and is my preffered method but it still comes down to knowing what you are doing.

Yup, Cattail knows his stuff. Some people just don't understand why you can't just vibrate the sh!t out of concrete. He told you the answer.

Cattail.
The next time you pour a wall, as you come around on the top lift, let the concrete flow in one spot until it reaches the top. vibrate the outside of the form and watch the concrete. Then stick the vibrator inside the wall and into the wet mix. Then come back here and tell us the differance.
Regards
Joe

I think a geographical location with local mix designs along with past ICF experience dictates your opionion's on vibration and here's why. From my 8 years in the industry it appears the older school ICF pros are all into vibrating ICF walls. Why, propbably most came from the likes of a waffle grid system and have carried that practice into todays more forgiving forms. Fortunately we run all pea stone mix here 3/8 stone with a mid-range plastisizer and fly ash at about a 7" slump. In a flat wall system this mix only needs external vibration by window lintels. We have proven this time and time again, the mix has the water content of a 4-5" slump but flows like a 7" plus with the appropriate mix design. We have cut uncountable test subjects in walls along with test at the rebar(#9) in our insuldeck system's which were only externally vibrated. This mix breaks at 5000 plus every time we have had it tested. I'm not disagreeing in anyones methods only pointing out that previous experiences dictate alot in life and there's more than one right way depending on your system. As far as the statement above from woulfcc goes fill a 5-gal. bucket full of water to the rim and stick your foot in, it will overflow for a second or two, pull it out and the water level will drop.

p.s. We have poured in excess of 1000 plus pours this way and have had no issues what so ever.

This is good although the focus of this has went from a consumers concerns to the issue of consolidation which was in fact his main question he is getting very good advice. All in all what it comes down to is experience in the builder of choice. Hopefully the builder that photogman chooses can gain some knowledge from this post.
Walltech makes some very good points in regards to the old waffle wall and the issues of voids, the damming effect can still be seen in some of the new straight wall systems on the market today. Several of the brands out there claim to be a straight wall because the foam is straight on both sides of the system, however this is defeated by the wide flat cross web in some of those brands which makes the flow of concrete even worse than the waffle wall. Then if you add the equation of rebar it can be even harder to move concrete through the wall. Always look for the wall system with the largest openings to allow free flowing concrete. You can also go with a larger higher tensil strength rebar to reduce the amount of damming areas in the wall some times this is money well spent.
We very rarely use a plastisizer but that is also good advice. We have also had many test done in regards to voids and having to remove foam and expose the concrete to satisfy the inspector, and in every case the inspector was impressed and has changed his or her attitude in this regard.
One other item that we use at our cold seams is to apply a 1/2" bead of butyl caulk in the center of the wall at the cold seam, this is probably not necessary but I get to sleep at night knowing that I have done everything possible to negate water infiltration into my customers home. Becuase no matter how much you consolidate concrete at the footing you still have a cold seam, two surfaces that are not monolithic therefore fluid can move through the joint (think about that).
So to photogman you are doing the right thing in getting knowledge I wish every consumer would take the time to ask the questions, it would soon eliminate the fly by the seat of your pants contractors and allow the quality contractors to win the bids, and not be the guy the consumer hates when he hands you a bill for fixing the mistakes that the fly by contrator made on your project.

Thanks very much for all your replies!  They will go a long ways for me sorting this ICF thing out.  The more I read about ICF basements and foundations, the more excited I get.  You are right, I need to find the right contractor to put in my foundation that has had alot of experience.  I can find tons of people willing to step forward and give it a go that have never worked with this stuff, but I believe I have to approach it like looking for a surgeon.  When I was diagnosed with Renal Cell Carcinoma three years ago, I didn't look for a surgeon to take my kidney out that wanted to get experience on my account, but rather went to Mayo and had a world-class physician that performed partial nephrectomies 3 days a week, 48 weeks a year.   That's the kind of concrete man I'm going to look for!  Then someday on a cold winter evening, I can sit in my home enjoying a nice wood fire knowing that it was done right.

Photogman,
I am glade to here you got it. I hope you enjoy this build.