Posted By ICFHybrid on 19 Apr 2013 08:53 AM

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, both techniques need to be applied in order to not have voids; proper concrete mix and internal vibration. This is what the Portland Cement study on ICF Voids concluded. A medium-high slump with internal vibration resulted in the best consolidated walls. Of all the ICF installers that are top notch, they all vibrate internally.

ICF VOID STUDY

WHERE the voids are located can be as much of an issue as the size of them. For example, a 2' x 2' void in the middle of a 9' high wall is likely not an issue, since the concrete above should provide support (becomes a 2' deep lintel). If these voids are below point loads (ie, beam pockets) or at corners, then there is more reason to be concerned.

I would contact the builder and have him cover the cost of an engineer review to start with (easier said then done if he is paid in full). If then becomes the builders resposibility to cover cost of repairs. If the original ICF installer wants to do the repairs, you should insist on an additional inspection by the engineer to be sure the repairs are up to par.

FBBP is right, non-shrink grout is the best way to repair small voids, but you may have structural concerns beyond a simple small void.

Of all the ICF installers that are top notch, they all vibrate internally.

I think that statement gives people the wrong idea. It might be better to say that the contractor is prepared to use vibration, but only when necessary. For example, my contractor only used it when the pour got away from him for a second and only with a very light touch. I have found no voids so far.

It is all in the mix and the placement. You can't "pour" ICF like it was just any old form to fill.

I would say that both good placement and internal vibration are necessary…and both are almost an art skill acquired by lots of concrete pouring experience. Doing internal vibration will always improve consolidation no matter how good the placement…but over-doing internal vibration will cause the gravel to settle to the bottom of the form which can significantly weaken the wall even more than having voids. You don’t want an ICF crew learning the trade on your project…

Hardly life and death situation. Replace foam and seal edges with PUF as stated before, get your hands on a motar bag from any mason supply store, a couple bags of Portland cement wet it up and pour at the top of each void thru a small hole. Whack the wall with a 2x and a hammer to consolidate. AS far as the foam, find a block supplier and cut the webs flush inside and install to replace removered sections

Posted By smartwall on 19 Apr 2013 01:37 PM
Hardly life and death situation.

Will you put that in writing and sign off on it?

Posted By Lbear on 19 Apr 2013 04:18 PM

Posted By smartwall on 19 Apr 2013 01:37 PM
Hardly life and death situation.

Will you put that in writing and sign off on it?

For Sure! Anybody with actual construction knowledge would. The house is obviously stable enough that he got it to the stucco phase without it collapsing so there is no way we are going to have catastrophic failure! OP has probed for any large void and mentioned the ones he found. No sweat! That the difference between actual building knowledge and reading a bunch of web sites.

Posted By FBBP on 19 Apr 2013 04:50 PM


For Sure! Anybody with actual construction knowledge would. The house is obviously stable enough that he got it to the stucco phase without it collapsing so there is no way we are going to have catastrophic failure! OP has probed for any large void and mentioned the ones he found. No sweat! That the difference between actual building knowledge and reading a bunch of web sites.

In the end only a certified engineer will know whether or not the wall is safe. In addition you did not take into account if the wall experiences ground movement, as in frost heaves, moisture content, earthquakes, etc., all of which can exert tremendous forces on the wall, more so than they are doing now.

Apparently the contractor had construction knowledge but failed completely in the assembly and execution of the ICF wall. Many structures experience catastrophic failures a year or many years later. Just because it hasn't failed as of yet doesn't mean it is not going to fail. Do a Google search and you will see some concrete structures that failed months or even years later because of initial faulty concrete construction.

The OP came to this website to get information and advice, of which the contractor who supposedly had building knowledge showed himself to be seriously deficient in said building knowledge.

Instead of just patching up the holes the OP needs to hire an engineer, get the walls inspected, photographed, documented and have an engineering study done to determine how safe or unsafe the wall is. The GC needs to be put on notice and have the State Registrar file a complaint against him. If 24" x 12" voids in over 8 spots is acceptable in a foundation wall, I guess we have different standards but I guarantee you that the local code and engineering department would not find it acceptable to have such voids.

As usual, Chicken Little screams "The sky is falling!"  about something he has no first hand knowledge or experience.

Posted By arkie6 on 20 Apr 2013 06:23 AM
As usual, Chicken Little screams "The sky is falling!"  about something he has no first hand knowledge or experience.

As you say!!
Is it just me or do more people find it a wee bit ironic that some people insist that ICF's are not for the diy or never use a contractor that has not place at least a mile of ICF walls, but then feel perfectly capable of telling everyone else just how they should build their ICF projects even though they themselves have never stacked a wall or place a yard?

I appreciate the advice, believe me! I did have a structural engineer look at a few of the smaller voids before I found the 2 larger ones measuring 24 x 12 and he was not concerned. I am waiting to hear back about the larger voids. I actually really appreciate your comments because I was tempted to just go ahead and fill the voids without having the engineer actually come out and look at them. I will wait to hear from the engineer first. One of the larger voids is above the basement door to the garage on a 2 story wall and the other is at the top of a walk-out wall.

Do you really think that there is a risk of the wall collapsing? The 8 holes were found on 7 different walls? I tried to post a photo of the larger ones but can't seem to. Won't the rebar help? My other concern is that I am not even finding most of the voids because I noticed that in the voids I found, there were portions where the was concrete on the face but completely void behind. How the heck do you check for voids when they are hidden behind a bit of concrete?

Thank you! Just down-loaded the report for review. Do you think that in reality most ICF foundations have voids in them to some extent but people are just not aware of it? I was told that ICF foundations are "over-engineered" anyway so even with a few small voids the structure should be OK. What do you think?

Posted By evary on 20 Apr 2013 12:45 PM
Do you really think that there is a risk of the wall collapsing? The 8 holes were found on 7 different walls? I tried to post a photo of the larger ones but can't seem to. Won't the rebar help? My other concern is that I am not even finding most of the voids because I noticed that in the voids I found, there were portions where the was concrete on the face but completely void behind. How the heck do you check for voids when they are hidden behind a bit of concrete?

evary - you are letting chicken little panic you.
As you have already concluded, the rebar will provide the tension strength even if it is not totally embedded. Even if one or two bars were not embedded at their ends, you would have more than enough redundancy to over come it.
Consider this. If you patch with non shrink grout, how will the compressive strength differ from the strength you would have had if the concrete was placed properly in the first place? It would probably be stronger than the original intent!
Also as I said earlier, the is no chance of catastrophic collapse because of all the bar. There may be sagging or bending in the walls or structure over time but even in an earthquake situation the likelihood of this structure failing prior to any other is very small.
By all means bring out an engineer if it lets you sleep better at nights. The poor lads need to make a living too!!
With regards to finding internal voids, I would not worry to much about them. If you are concerned and your house is all enclosed you may be able to see shaded patches with an infrared /thermal imaging camera. There should be a discernible difference in the wall temperature were the lack of concrete lies. The larger the difference in temperature between the air and the wall the more likely you will see them.
Anyone with concrete knowledge can pretty much predict were the voids are most likely to occur. There is little chance of a void where the is no obstruction unless the mix was totally wrong. That does not appear to be the case here or the voids would have been much worse.

FBBP By your reasoning then, it is OK to cut holes any which way thru floor and roof truss members? Or perhaps skip the occasional wallstud or lintel also as long as the finish looks good and it dosn't fall down before construction is complete and the contractor walks away with his paycheck? "Don't worry Bubba ittle be plenty strong enough without that" That is probably why the building inspector now gets a final looksee and signoff before the walls of a stick built gets closed up.

How is this any different than large voids left in the concrete? Get enough issues with ICF and I won't be at all surprised if ultrasounds don't become a mandatory residential inspection and a minimum void area established before construction can continue beyond the wall pour...

You are of course entitled to think finding 12X24 voids in concrete walls is OK, but I am also entitled to think that it is not...

Evary, internal voids might be located with IR as mentioned. They also might be found with ultrasound.

Voids in lintels are particularly troubling as the lintel needs to be strong enough to support all the load over the door or window opening below. A garage door lintel is VERY troubling as it spans such a large opening. Imagine a concrete bridge truss with a void. Without the compressive strength/support of concrete, the rebar acts more like a wet noodle than steel re-enforcement.

You can call me chicken little if it makes you feel better(it's ok, I got a pretty thick skin but if I found a 12X24 void in my ICF wall I would be VERY concerned by what I cannot see. You found 3 of these...

Thank you for your reply. What is IR? Is it very expensive? My basement is 5500 sq ft so I am assuming it would be extremely expensive to do. How do they ultrasound an entire walk-out basement foundation? It will be two years in July since the foundation was poured. Do you think I would have seen signs of trouble my now? Also, what/where is the lintel? I have Logix brand blocks. One of the large voids is over the garage man doors in the basement going up to the garage. One is over a basement walk-out large window. I appreciate any and all opinions. I have no construction background and it seems that even my engineers have differing opinions. Thanks everyone!

Ron - if you don't know the difference between wood stud assemblies and reinforced concrete walls, than I sorry but this is not the place to educate you.
With regards to voids. Consider that there are many successful post and beam type ICF walls place where more than 50% of the wall space is not concrete.
Please read OP's post again. "basement door to garage" not a big span. With joists over it to support the wall above. Also I did not suggest leaving if void.
Mentioning concrete bridges just indicates the lack of knowledge between the different types of concrete structures. One is mostly self supporting while a basement is totally supported at ground level. However if you are from some area where they use a lot of salt for deicing you will find a lot of inservice bridges that have huge sections of missing concrete. Again much redundancy built into reinforce concrete.

fbbp, yes I know the difference between wood construction and concrete construction tecniques. The do share one very important similarity, that being they are both the sum of their parts/assembly. When you start leaving out parts in any structure, you loose integrity. Your reference to post and beam is an excellent one. The posts have added reenforcement to make up for the missing wall sections and transfer the beam loads(also re-enforced) to ground. How about voids in the posts or beams? That would be very bad as they are now even more important to the overall structural integrity...

Evary, IR stands for Infa-Red. Also known as a thermograph. It looks at Infared heat energy instead of visible light. Voids will conduct heat thru the walls differently than solid concrete and may be visible with an IR camera.

The Lintel is the re-enforced structure found above any window or door opening in any load bearing wall type. It is often called a header in wood framed construction and either consists of a built up or solid wood beam. In ICF/concrete construction additional steel is added, either a rebar cage or stirrups tying horizontal rebar vertically to upper horizontal rebar. It is a basic bridge span and must be re-enforced to transfer loads above it, out to the area on each side of the opening(also re-enforced) just like the above mentioned post and beam construction. That is why I used the concrete bridge beam analogy as they basically serve the same purpose to support a load across a span without collapse...

Posted By Ronmar on 20 Apr 2013 03:02 PM
FBBP By your reasoning then, it is OK to cut holes any which way thru floor and roof truss members? Or perhaps skip the occasional wallstud or lintel also as long as the finish looks good and it dosn't fall down before construction is complete and the contractor walks away with his paycheck? "Don't worry Bubba ittle be plenty strong enough without that" That is probably why the building inspector now gets a final looksee and signoff before the walls of a stick built gets closed up.

How is this any different than large voids left in the concrete? Get enough issues with ICF and I won't be at all surprised if ultrasounds don't become a mandatory residential inspection and a minimum void area established before construction can continue beyond the wall pour...

You are of course entitled to think finding 12X24 voids in concrete walls is OK, but I am also entitled to think that it is not...

Evary, internal voids might be located with IR as mentioned. They also might be found with ultrasound.

Voids in lintels are particularly troubling as the lintel needs to be strong enough to support all the load over the door or window opening below. A garage door lintel is VERY troubling as it spans such a large opening. Imagine a concrete bridge truss with a void. Without the compressive strength/support of concrete, the rebar acts more like a wet noodle than steel re-enforcement.

You can call me chicken little if it makes you feel better(it's ok, I got a pretty thick skin but if I found a 12X24 void in my ICF wall I would be VERY concerned by what I cannot see. You found 3 of these...

You will find very quickly that those who did not wish to have a civil discussion will resort to name calling and attacking ones character. We can disagree but the name calling and personal attacks are uncalled for.

I know a few reputable ICF contractors and NONE of them believe a 12x24 void in over 8 spots, in addition to many other voids, in a foundation wall is acceptable. If FBBP believes that numerous 12x24 voids in an ICF foundational wall are acceptable, then we should assume that he allows this type of standard on his construction jobs.

What did you mean by, "you found 3 of these..."?

Evary - Again...get your state contractors board to engage the contractor that did this project, get an inspection by a competent engineering firm, and seek legal remedy to recover your cost of resolution. You should not make any decision on the correct course of action or try to affect a structural repair on your own based on "expertise" from this forum or any other forum.