I have discovered 8 holes in my ICF foundation - 3 of them are at least 24 x 12 inches, the rest are somewhat smaller. How do I fill these holes? What type of concrete do I use? The foam is not reuseable - can I just use spray foam over the concrete? I would appreciate your suggestions.

A zero slump, no aggregate concrete would be easier to pour in. I would use rigid foam for any large holes and spray foam for small holes and gaps.

I had my suspicions about the foundation as the house is still under construction and many other things were going wrong. I literally took a marshmellow roaster and poked holes all around the interior of the walk-out basement and found the holes very quickly this way.

I had my suspicions so I took a marshmellow roaster.

Where do I get the rigid foam from? Would the provider of the blocks have it?

If you are willing to glue them together, any of the big box stores should have 2" XPS or EPS.

Posted By evary on 18 Apr 2013 07:05 PM
I have discovered 8 holes in my ICF foundation - 3 of them are at least 24 x 12 inches, the rest are somewhat smaller. How do I fill these holes? What type of concrete do I use? The foam is not reuseable - can I just use spray foam over the concrete? I would appreciate your suggestions.

Was it a trained and seasoned ICF contractor? Did they vibrate the walls when they poured? They should have used a pencil vibrator to get proper consolidation and no voids.

thank you!

No, it was not a trained and seasoned ICF contractor - if I only knew then what I know now. They apparently did vibrate but I doubt they used a pencil vibrator.

evary - assuming you have no cladding on the inside or out, it is easy to see voids in ICF by placing a halogen work light in the inside after dark and walk around the outside.
If you know where the voids are and have not removed the ICF panel, punch a small hole just big enough to get a about 1" funnel in at the top of the void and pour in a runny mixture of no shrink grout. Grout is just about self levelling so it will fill almost any void. You may have to foam or tape any joints to prevent the grout from leaking.
If the panel has been removed, you can use the same non-shrink grout to dry pack the void.

Unfortunately, I already have stucco. Will this technique still work? Do you have any other suggestions? So greatly appreciated - this is so stressful ...

The patching will. The light? probably not but might be worth trying. Larger voids can be found by tapping the wall or running something that makes different sound, like a toy tractor or truck over the walls. Unless the voids are in the areas of headers, it is unlikely that the structural integrity of the wall will be seriously effected. A properly detailed ICF job has a great deal of redundancy built into it.

My brother is an engineer with one particularly bad experience with an ICF wall a few years back. Inexperienced contractor didn't consolidate. They condemed all but about 10' of the entire wall of a rather large house (multi-million dollar build). It was a 4" core, which is more difficult to consolidate, but apparently the contractor didn't really even try. Initially found voids by slapping the foam. They pulled off one section and the owner and contractor about had a seizure. "Is there any way to do this less destructively", so out came the welding wire marked with the foam thickness and away everyone went poking the walls. Voids everywhere... He was understandably concerned when I told him I was desiging a ICF home

How thick is your wall core? Are you sure you have found all the voids? If I read correctly, you say there is stucco on the outside already? If so, that probably precludes poking any of the outside wall foam? You may be able to tap the outside(rubber mallet on a piece of plywood against the stucco) and listen for any anomolies. Then you can dril thru the stucco to confirm? It is the relationship of the concrete compressive strength to the rebar's tension and shear strength that makes a concrete structure strong. You start converting the wall to a conglomerate of concrete blocks, you start to loose strength, perhaps to a significant level. What percentage of the wall do you estimate are void space. Yes, a properly specced ICF wall should be more than strong enough by a large margin. But these walls must hold up all the roof load and be able to withstand a certain ammount of lateral stress in earthquake and high wind. You are quite literally betting your familys life on this... That is the drawback of ICF's(or any concrete poured wall for that matter) They must be poured correctly as it is very difficult to go back and fix properly later to the same level of integrity as a proper initial pour. This might be something you want to get an engineering consult on, at the very least for peace of mind...

Good Luck.

Posted By evary on 18 Apr 2013 09:41 PM
No, it was not a trained and seasoned ICF contractor - if I only knew then what I know now. They apparently did vibrate but I doubt they used a pencil vibrator.

First, get the State Registar of Contractors involved, file a complaint against his license. Get the BBB, file a complaint. These people need to STOP building and destroying peoples dreams, lives, and stealing their hard earned money. I'm sorry, this type of stuff really drives me mad. People invest their heart and lifes fortune into a home and then these contractor yaks come around and rip people off by doing horrible jobs like this. They should not be touching ICF if they never used it before. Ridiculous.

Next thing to do is hire an engineer and have them examine these walls. Since this is a structural issue and voids of 2 feet by 1 foot in diameter is beyond some minor "air pockets". The wall could collapse and kill you and your family.

Take photos and document everything. Get an engineering report, this is key. The report will detail the poorly built walls and how they are structurally unsafe.

Add this story to the long list of horror stories about how ICF's are NOT a job for non-ICF professionals.

I bet he used an external vibrator which have been proven to be quite useless or they did the orbital sander on the outside walls, which is also been proven to be a waste.

They should have used a pencil vibrator to get proper consolidation and no voids.

Vibration is not a substitute for using the proper concrete mix and good technique in "placing" the mud.

Agreed, assuming this clown even has a license, get the state contractors board involved to shut him down, get an inspection by a competent engineering firm, and seek legal remedy to recover your cost. This not a DIY repair.

This is typical of how these threads get so convoluted.
OP asked only two questions. How to repair the concrete and where to get the foam!

I would not call it convoluted when simply patching a serious problem might not be the correct answer...

Posted By Ronmar on 19 Apr 2013 10:45 AM
I would not call it convoluted when simply patching a serious problem might not be the correct answer...

I agree. The OP has voids in his foundation wall, some as large as 24x12. This is a potential life and death scenario with a complete wall & structural collapse. The OP does not recognize the severity of his issue. Bad questions don't deserve bad answers.

My advice: DO NOT REPAIR THE WALL! Contact the Registrar and an engineer. Have the engineer inspect and document the damage, hire a lawyer. The minute you start repairing the damage yourself, you lose your recourse and become your own liability & warranty source.