A few things regarding wall compression that I have picked up while researching ICF:

1. Assuming you aren't using a continuous vertical wall tie system, a higher density foam will compress less than a lower density foam. Type IX (2# nominal density) EPS has almost double the compressive strength of the more commonly used Type II (1.5# nominal density) EPS.

2. ICF wall ties with a thinner profile (when viewed from above) will impart less compressive forces on the foam (due to concrete hitting the ties during the pour) than will thicker profile ties.

3. Raise door bucks off the footing 3/8"-1/2" prior to securing to the forms so that any form compression you do get is ~equal and not overly influenced by the rigid door bucks.

4. Hang your vertical rebar from the top horizontal rebar with tie wire to pre-load the forms. This helps to pre-compress the foam forms prior to the pour.

Thanks Arkie, we want good info like that, not bickering. I have not used TF, (have I said I would like to?) but I doubt they would compress at all. And don't think an uneven footing should be part of this discussion. We all know a footing should be as close to perfect as possible.

EXACTLY, Brad! And, I apologize for being a party to "the bickering", but how do you just let personal
attacks, and inaccurate allegations, go by the board?

Now the truth comes out. 3 pours Sipper? Get in the saddle for awhile before you tell me how to ride.

Kevin
www.icfinstall.com

While witnessing 3 pours is not a lot of experience and would make it difficult to form a complete opinion, I have not witnessed any TF pours and it is common sense that TF would not compress as much as other ICFs or at all.

But lets hear about some other ICFs.

check out www.tfstructures.com then photos then cold storage. Picture of gentlemen in manlifts pouring.

hmmmm look at the LASER on the top of the wall at the corner, during the pour. why I wonder?

TF may be no worse than many blocks, but lets not hear all its sales accolades all the time, ok? This thread started fairly about compression, and once again as in countless other threads, TF is shined and polished for the world to see.

I am just awful tired of this forum hijacked by sales oriented people; this seemed like a great thread to vent; and timing was aprapos, if I do say so myself.

Giddy-up! Let's get this filly moving. This thread is turning into a bad hoss!

Peace, I'm OUTTA here.

Love, Kevin

Irnivek,
That is my guys in the picture pouring over 20' tall walls that TF is using. The reason for the laser is because on the lower lifts we poured through the side of the system and as we worked our way up we would slide down the panels, thus we could not screw the channel on till we got to the top. When we get to the top lifts we would use the laser to shoot the c-channel so the building was level.
When working on walls that are not as big such as 12' or shorter we would have shoot the channel before the pour and not worried about it. I do this because if there is a footing dip or other imperfection the channel takes it out. I like it enough that I us TF's channel on one of the blocks I use (just don't tell them).
As long as the ties can float separately from the poly I have never had much trouble with settling.
With that said I would not let more then an 1/8" go on a site.

Not too bright on my part to jump into a fire with a can of gasoline but i will make an attempt to calm things down a bit (or not).

I can say based on observing a hundred pours that NUDURA does not compress (measureably). Why do i say measureably? Because compression some always exist (even with NUDURA) however small -- if you push down on a 2x4" with your hand it compresses -- the point is that you can't measure it with a tape measure. Compression is irrevelant if you can't measure it with a tape.

NUDURA also does not float because of the mechanical lock design. Floating is sometimes a bigger problem even than compression -- a combination of compression and floating means -- irregular top plate -- which is not acceptable.

To someones point above regarding the slab not being level: When presented with a slab with dips and valleys the ICF will always follow it if it is not properly supported. HOwever, the block following the contour of the slab is not compression, but the net result is again -- an irregular top plate -- which is not acceptable. If you properly support the block at the floor (on both sides) where it is "in the air" over a slab valley you won't see this problem. I see this as part of the job of the installers to correct the slab -- since it's very very rare that it's perfect. I've actually only seen one or two slabs that was +- 1/8".

Although i believe all blocks that do not have a fully continuous furring strip will likely have some compression (and these blocks exist) I have no interest in discussing which blocks (in my opinion) compress the most - only that compression and floating are not an issue for me. One final point, I adhere to the ACI 318 with 4' per hour as a matter of standard practice. If your block is compressing a little you might try backing off to 3' per hour. Regards.

NUDURA is one with the least compression. They have full height ties and the plastic hooks, with I think three levels of connection. When pouring you will often hear that last click as the concrete forces the forms together more than you could during assembly.

I can not take one hour to pour just 4' high. But I bet the pumper would like it.

Brad,

Based on your experience you likely already know this but (for others that may not) -- if you create a handle on a 3' 2x4 using a skillsaw (or use a rubber mallet) and strike the block as you go up on top of the interlock you'll get the last click. To installers not familiar with NUDURA this may seem like extra work since without a mechanical interlock it would only damage the interlock -- but actually the fit is so tight that even water has to work to get out and the concrete cannot cause floating even with heavy vibration.

I see your point on the 4' per hour but as you know this does depend on the size of the job. If you're doing several hundred linear feet you will be lucky to be back around in an hour. E.g. 6" block, 4' height, 500 linear feet is about 37 yards. Nothing wrong with 15 minute trucks. I think it's actually in ACI because it's difficult to internally vibrate more than 4' at a time properly. Anyway, my suggestion was that if someone had issues with compression they might be better served to back off on the pour rate - perhaps with 30 minute trucks or perhaps with less of a target height per hour.

With NUDURA we strike the top of each tie with a rubber mallet, and still don't get all the clicks. Then we are thrilled when we have to remove a form for some reason or another.

Would this best summarize this particular thread? What types of ICF's compress the most? - BLOCK ICF's What types of ICF's compress the least? - VERTICAL ICF's. How do you limit compression in BLOCK ICF's? - flat/level footings ( 1/4" in 10 feet ) - always adhere to the manufactures recommended pour rates which in most cases are consistent with ACI 318, which depending on the temperature is 4 ft. =/- per hour. - slot the holes in the strong backs for the screws. - How big a slot? - use the correct srew---??? - do not over tighten screws to the strong backs -place screws near the top of the slot in strong backs to allow for movement -strike the top of each block with a mallet,special designed tool.your hand .......... - chose BICF systems with a thinner web profile - raise door bucks off the footings 3/8" prior to securing BICF's. -hang vertical rebar from the top horizontal rebar with tie-wire to preload. -laser level the top of the wall after the pour. How do you limit compression in VERTICAL ICF's? There is no negligable foam compression if any to limit because of the inherit design of a VICF. Can you predict compression amounts in a BLOCK ICF? - in solidly set BICF's and well molded forms, 3/8" in 12 ft. pour. Can you predict compression amounts in a VERTICAL ICF? - there is no negligable compression to predict.

The 4' rules is for vertical concrete and applies to both scenarios and unless the manu suggests less this supposed to be your pour rate. For many blocks (and perhaps verticals) you can fill the wall all the way up in one pass without a problem -- the rule is in place for proper consolidation since one cannot internally vibrate concrete properly that is 10 feet deep.

If the slab is not correct verticles will still be corrected at the top of the wall by cutting to height. I just prefer to correct the slab first and go up. This make life easier. Based on your post (Joseph) you have some experience with block ICFs that compress - but i must tell you i've gone 40 to 70' feet (10 -15 feet per pour day) with no measureable compression whatsoever from floor to floor and NEVER measureable compression in 12'. If i had 3/8" across 12ft I wouldn't be in this business.