I rarely use 4" ICFs, who does?

Hi Brad,
I can't say I've seen a 4" ICF? Height or width? Or concrete core?
I've used 4" high to meet design heights. I've used 6" overall width wall forms for interior walls (considered non-load bearing), and I've often used 4" (or 4.5" to be a little more accurate) core fairly often. (commercial, residential and industrial).

I have used a 4" (concrete core thickness) once. It was a free standing office inside a huge non-climate controlled steel garbage transfer building, worked great there, quite and dust free.
But my main competitor uses 4" all the time above grade, but do the the strength limitations they end up using structural lumber for headers. I don't like to use wood in my walls so I don't do it.

I'm surprised at the structural limitations above the windows doors, but I can see the problem if there is only a foot or two available and the spans are large. I was involved in a 5 story building (not my job, but wished it was!) that used only the 4.5" core for the entire project, but I guess when the engineers are looking at the whole structure, more can be done (lots of shear walls, elevator core, etc.). All the windows and doors had plenty of wall above, so no lumber whatsoever, anywhere in the whole building! I agree with you though - NO wood, especially above the windows/doors - I don't like those kind of transitions that have to be dealt with when finishing. Keep it consistent!

I think part of the structural problem with the $" is rebar cover over the lintel rebar, if your rebar cover is specified to be 1.5" you could not have 2 #5 rebar side by side in a 4" ICF.

What did you use that 4.5"?

In Waterloo Ontario. The internet only has one reference to the project I speak of. If you can click on the link, or cut and paste it, you might be able to read through the project. I do mostly Durisol stuff, hence the 4.5" core, but they have cores that go up to close to 11".
http://www.efficiencyvermont.com/pages/BBBD2006/docs/Straub-Notes%20From%20the%20Field.pdf
Neat project. Hope you can get it/find it.

Looks interesting. Anyone else use much 4"?

Off and on. I actually did my own house out of 4". I might do 6" in my next house. The thing that appeals to some people is the 8" to 4" to use the ledge for floor joists. I try to sell as much 6" as possible, but some people just like 4". I think Drury uses 4". Not real sure about that though.

Do you do all ICF lintels? Do any special things apply only to 4"?

Yes, we do ICF lintels. We usually like to use Helix steel fibers with 4" to get better consolidation. Other than that, not really.

What, about, is the biggest lintel you can do? Is each job engineered?

dwangle,

Do you use any rebar with the Helix steel fibers in 4" ICF lintels?

Rebar will still be required for lintels in all ICF walls using steel fibers. Someday I assume they will get smaller lintel lengths approved but so far I'm not aware of any "approved" steel fiber lintels.

We have engineer stamped drawings for all of our form thicknesses. I don't have the tables with me right now, but we are pouring a 4" garage tomorrow(Mon.) that has 10' garage doors with 10" of concrete above. Of course, you have to put re-bar out the wazoo in it.

Alton,
Yes, James is right, you still have to use rebar for the lintels.

If you could tell us the rebar detail for over those doors, I would be interested to know.

We had 2- #5 clumped together on the bottom of the lintel with stirrups every 4" appr. 3' both ways of the edge of the door holding the bottom rebar with a #4 at the top of the lintel. Nudura has the rebar schedules on their website. I know my explanation is probably confusing to you, but it makes sense to me. :)

We are used to the description, so we understand, so you have 4' in the middle with no stirrups.

What is the rebar cover minimum?

You were right about 1 1/5" cover - for a non-covered concrete wall. But since it is a covered wall, you are allowed 3/4" cover. Is that what you were asking?

Yes hat is what I was wondering. I do like the NUDURA engineering, it is very comprehensive and I think not so extreme. That is worth something. Maybe I should reconsider using 4".

What do you see as 4" limitations?

A little in the lintel design - not much though.
It is hard to hit the hole with a pump hose. :)
Your wall won't have quite as much wind, sound or fire rating.
It is a little flimsy setting up.
That is what I can think of right now.