I've done a search on here and either I missed it or there wasn't any discussion about blowouts when doing ICF.  How often does this occur to you, what is the main reason you have found it happens, what do you do to to remedy the situation.  I deal with Nudura and have had only 2 minor corner blowouts.  This was a result of too much concrete being poured too fast into the corners.  I was able to piece the broken block back into place, then screw plywood to the intact block around it to finish the pour.  I then went back and removed the plywood and used canned foam to reinsulate and secure the block since it also adheres.  

So what is your experiences guys? 

Rykertest - Blow-outs and Bow-outs can occur with almost any system. As you have pointed out the vast majority occur due to "pour pilot error" and inexperiance. Have seen my share over the past 17 years - including some using my own system (Isomax). We have with us on every jobsite a few sheets of OSB Board, a box of threaded Rod and a box of wing-nuts with washers. Step one: DON'T PANIC - direct the pump to another area of the pour. pre-drill holes into 2 sheats of the OSB Board, place both sheats of the OSB board on eather side of the blow-out area, insert Threaded rod with washers and tighten with wing-nuts (Size of OSB board depends on Blow-out). Our last blow-out was in 2003...when someone forgot to bring the Threaded Rods and wing-nuts with them to the job-site!!!

ok, soooo....blow-outs are not a favorable discussion on this forum. Mind you, prevention of blow-outs is something else. You will find a lot of contributors with different ideas and opinions. My view point: Yes, I had a view blow-outs because of this and that. And yes, I will do what ever I can to omit this nasty occurence.

It is all in the prep and the mobilization (thanks Kevin) and the game plan to prevent blow-outs.

Blow outs as already said in some fashion are installer error. My last blow out was 6 weeks ago, about 1/2 a wheel barrow, someone forgot to 'button up a corner' where we were making corner blocks, wall was changing from 6 to 8" so we ran the standards into the corner and closed it up with 1 1/8" plywood, nice and strong provided the thing gets properly screwed off...

The one before that was in '04, corner block split wide open, the next day upon examination and remembering someone stepped on a corner, it turns out it was the one that was stepped on and somehow it managed to be put in on the bottom course, not exactly the place you wanted it.

So as you can see, installer error.

Don't freak out, don't get excited, move on and have your crew open it up, clean it up, put it back together and pour again. That last one we had, we knew who was suppose to be doing the sewing job on the plywood, it's a guy who wants to be the crew leader allowing me more time off the site and pursueing new work...we made him buy drinks that night...which far exceeded the $ 10.00 or so of concrete we lost.

I agree with the rest blowouts do occur and even though we would like to blame the block it is usually something that was missed in bracing.
Ocassionally it can be a defective block again very rare for it to be the blocks fault and most like it is damage to the block from handeling.
The third item that is very common is a blowout from the incorrect slump, this is where it is so critical to know what the manufacturer of the block recommends for slump and at what height to pour, this is generally at the 4' level per lift.
Now lets talk a little more about slump, our most recent was in September of 08 on a commercial with 18' side walls, the first 4 trucks where slump tested and did very well, we stopped testing at that point as we (assumed) the ready mix batch master had it dialed in the very next truck came and I was showing one of the crew how to finish a filled window well, I heard the rpm of the pump truck change just intime to see a 9 slump coming out, before I could stop it the corner which was braced very well blew out.
We immediatly slumped the truck but it was so high we could not get a reading it pretty much flattened out like a cow dropping. We pumped the product that was in the pumper back into the truck and rejected the truck . The crew was removing the foam in that area and pulling out the concrete to a level where we could put the foam back in and scab the area with plywood, Now the most important part of this is that you realize once the bond of the tie between the inner and outer panel has been defeated you must reinforce booth sides it is a common mistake that gets made to only reinforce the side that blew out.
The trucks guage read that it was a 5 slump and this is why I have always tested all my trucks, and as soon as i did not it bit me. The next truck was also reading a 5 slump on the guage and it tested out at 4.5" and this is why I do not trust the trucks guage and do the slump test.
We have had 9 blowouts in the 7 years or so that I have been doing ICF and only two of them where attributed to bracing the rest where all attributed to slump issues.

Guys,

This is a very important discussion as this separates the ICF world from the typical poured in place concrete wall with the massive removable forms. From your experience are the blow outs at the most bottom level of the pour? If so does it make sense to preemptively brace the bottom of the wall with OSB on both sides with pass through ties about 4' high? I know this adds materials and labor but what about the concept? I am really researching SCC mixes and several studies have shown that while overall head pressures are higher than the typical ICF mix they still do not equal the full hydraulic model used to calculate the head pressures. The question is what PSF load can the ICF truly handle at the bottom most course? I know that variables such as EPS density, tie spacing come into question but I have yet to a find a definitive answer.

Leonard

I have been installing Eco for six years and have never experienced a corner blowout, the most important thing wihile pouring is to pour as far away from the corners as possible thus avoiding stress on the corners.

Rock is dead on about the corners. However it's been discussed already and some do pour directly in the corner. Not common practice in my book therfor no blowouts on my part yet,knock on wood. Working with the integraspec block poured on numerous occasions 11 to 14 ft high in one pass ,normal interior bracing and no osb in the corners. This is one of the most fogiving blocks. The boys are wright most of the blows are caused by poor installation process!!
Cheers!

Of course all of the pros who participate in this forum are aware that all ICF systems are not "blocks", however, prospective home owners, and builders who are new to the concept, may not be aware of that fact. Wouldn't it be interesting to hear some field reports that address the issue of "blowouts" from anyone with experience with other types of ICFs, such as TF "the vertical system"?

If you want real blowout stories, talk to the pumper or convey operators. They have all the best stories. Like the time it took 6 hours to place 14 yards of mud classic. That was a vertical form by a do it yourselfer, first time icf attempt. woof.-Tom

Key words in the previous post "Do it yourselfer". Of course there are anecdotal horror stories about virtually every building system, or product, that is available.

How can the boom pump operator assist in preventing blows or bows or hinder you during the pour? Seems you'd want a pump operator who has a few ICFs under their belt. Would want to have someone with ICF experience, not just traditional formed concrete walls.

Having had a shot at handling the tremmie during a pour of 8' walls of 6" Reward forms in two lifts, I found it an effort at times as the operator sometimes didn't keep the tipe directly over the forms. So I had to tug and push to keep from splattering concrete all over. No blow outs or bows on that job.

BUT on another pour using Logix 6.25" forms had a half yard blow out at a 90 degree corner due to a fellow on the boom pouring directly into the corner. Second was a bow out at bay window bucking and a third a bowout at another series of 45* corners with windows. In retrospect, 2 and 3 should have been braced more sturdily. So can't say the ICF was the culprit. Better bracing and proper pouring technique would have precluded all that. By the way I was an innocent bystander on the second job, but learned a lot. Dave

On the Cayman Islands we have had a problem with the block itself. The tooling to make the block was never cleaned and when they applied the right amount of steam to achieve the 1.5lbs density the block was uneven, literally - the one side of the panel was higher than the other and the plastice web was bend. So, instead of cleaning their tool they applied less pressure and less cooling time. The block came out straight but at less than 1.0lbs density. We had a couple of blowouts in the corner where the webs did not fuse at all.

Blowouts are a reality, like speeding tickets. It is what you do when you have one that makes for an overall good day or will put you into misery. Keep calm, cool and collected, take a deep breath, and fix the problem. No time to blame anybody at that moment - the job needs to get done while concrete hydrates.

I have often thought to invent a "blow-out" kit - just kidding!

I installed mostly TF this past calendar year and no blow outs. When I pour I start in the corners that way the crete flows away and keeps the pressure down. Besides with TF the bracing is on the corners (2-2x6 in a L shape) so they can take quite a bit. The rest of it I brace about every 10' and no problems. The previous year I had 2 (as stated installer error) 1 with the verticle and one with block. The main install mistake with TF is not getting the panels tight. The biggest thing to prevent blow outs is experience and unfortunately the best way to get it is to have a couple of blow outs. The important thing to remember is its not a big deal and you lose minimal amount of crete, don't get excited and take you time and fix it. The TF is really easy to fix.

I'm not a concrete foundation pro but in preparing for my ICF basement pour I talked to a lot of concrete foundation contractors who all had stories of conventional "massive" forms blowing out.

Blowouts can happen with any concrete forming system and are almost always do to oversight (missing/improperly installed ties), lack of bracing, or slump/pumping rate issues.

So blowouts are really not an ICF issue - they are a concrete forming issue that can happen with any system.

No I'm not an ICF salesman - just a guy who did his own basement with no problems because I studied, did a careful job, didn't allow myself to get rushed and double checked everything before calling the pumper and concrete truck.

Gregj,

Thanks for posting.  I hope to be in the same position.  It seems that one cannot brace enough.

Leonard