While there is a lot of scattered info on this site, I would appreciate some FOCUSED input and opinions for this specific main floor combination.  If hotels and condo's use 4" ICF walls, it would seem that applying the same dimension to residential walls would make for thinner (more normal looking thickness) walls at doors and windows.  With the R value of concrete being negligible, the difference between 4" and 6" should also be negligible.

The foundation of this bungalow would be 8" x 10' TF Vertical with standard concrete.  Rather than the 6" main floor, I would like to use 4" x 10' TF with SCC (to avoid consolidating) with the lowest "slump" to minimize form pressure.  My local SCC choice would be Aguilla by LaFarge.  It is encouraging to see more SCC studies coming out.  The upcharge to SCC is small enough, and the added benefits seem great enough to use it in the 4" wall.  Strength is double (50 - 60 mpa) the normal concrete of the foundation . Since TF has the advantage of splitting the foam horizontally, the drop of the concrete in my case is (at most) 5 feet, and not 10' with block systems.

I would appreciate any open responses on aggregate, additive suggestions, and your experiences with this proposed combination. 

Direct replies is equally fine.

This interests me as well. Hope you get some replies. I am certainly interested in reducing the amount of concrete expense if it does not change wall strength.

I have wondered about those fibers that can be added?

Posted By Full ICF Homes on 02 Apr 2010 08:34 PM
While there is a lot of scattered info on this site, I would appreciate some FOCUSED input and opinions for this specific main floor combination.  If hotels and condo's use 4" ICF walls, it would seem that applying the same dimension to residential walls would make for thinner (more normal looking thickness) walls at doors and windows.  With the R value of concrete being negligible, the difference between 4" and 6" should also be negligible.

The foundation of this bungalow would be 8" x 10' TF Vertical with standard concrete.  Rather than the 6" main floor, I would like to use 4" x 10' TF with SCC (to avoid consolidating) with the lowest "slump" to minimize form pressure.  My local SCC choice would be Aguilla by LaFarge.  It is encouraging to see more SCC studies coming out.  The upcharge to SCC is small enough, and the added benefits seem great enough to use it in the 4" wall.  Strength is double (50 - 60 mpa) the normal concrete of the foundation . Since TF has the advantage of splitting the foam horizontally, the drop of the concrete in my case is (at most) 5 feet, and not 10' with block systems.

I would appreciate any open responses on aggregate, additive suggestions, and your experiences with this proposed combination. 

Direct replies is equally fine.

All-Sask,  

A couple of somewhat focused comments on your post:

4" wall are generally less common because of some of the engineering of height to width ratios.  YOu see them occasionally with (perhaps) more progressive engineers because they recognize that they are still stronger than typical reinforced CMU.   NEvertheless, we have a different code requiring more steel than CMU typically.    

I don't agree with "more normal looking" thinner etc.  A great many homeowners and commerical folks absolutely love their thicker walls -- if you go into an expensive stick house you'll find that they finish them out to create the illusion of thicker walls - thats because it says quality and safe and etc.  

You are correct R-value is negligible but thermal performance as well as wicking is not.  The thicker wall performs better in most climate -- in fact the 4" wall is thin enough to actually heat up sometimes in Texas -- remember if heat is comming in it has to overcome the thermal capacitance of the concrete before it can start working on the inner 2 5/8" of foam.  These are things not contemplated by r-value -- which is a little on the silly side itself in terms of how its measured but thats a different thread for sure.

I'm fine with SCC - but wouldn't pay much more for it.  I'm a fan a vigorous internal vibration - if you're trying to avoid vibration you might look at how your bracing or what forms you use because your better ICFs can take it fine.   and yeah that could be another thread as well (and is).

What are you saying about spliting the form horizontally and this being some type of advantage?   Are you saying that your going to pour 5' at a time??  I pour 4' per hour and go to 12' to 15' feet per day (all the time) to the tune of over 200 yards per day and vibrate away.   BYW - the concrete falling more than a few feet problem of some years ago has been proven to be an old wives  tale.   Even at 50' no measureable segregration noted in the tests.    Hope this helps.  Regards.

Thanx Texas, it is always good to hear from any experienced person, and that you certainly are. There will always be Ford:Chevodge comments about these systems, but all educated comments are food for thought ... for me.

I am not familiar with the height to width ratios you speak of, and one always has to bow to engineering principles.

As to splitting the TF Vertical at 5 feet, you can still pour the 4 feet and then slide down the top 5 foot piece, pour 4 again and then 2. What I was thinking was that if you drop a balloon full of water from 5 feet, it breaks but at 10' high, it hits with more pressure, and even more as you go higher. As water does not compress, the physics of anything hitting with more speed is fairly simple. Getting hit with a grasshopper when standing still is a whole lot different on a motorcycle at 60 mph.

As to wall thickness, where I am, main floor ICF is rare, not common, and acceptance is neither rapid nor assumed.
These may not necessarily be expensive homes. We are shooting for EnergyStar rating at the least expense. For example, what would Habitat design?

There is no linear cost comparison between a 4 and 6" wall (ie: 50% more concrete) and I haven't factored in taper top forms, 10% upcharge for SCC and possibly the increased rebar size. While it will be up to my engineer to determine those criteria, I am just focusing on this one factor. Increased wall thickness means more labor and materials for build outs, jam extensions, and the like so thicker walls come with more price and not everyone appreciates those costs.

I opened the first inspection business for home buyers in my province (30 years ago) when people were asking me "What in the world do I need that for?" Reality and perception changes require experience, time and education.

Thanx Texas, it is always good to hear from any experienced person, and that you certainly are. There will always be Ford:Chevodge comments about these systems, but all educated comments are food for thought ... for me.

I am not familiar with the height to width ratios you speak of, and one always has to bow to engineering principles.

As to splitting the TF Vertical at 5 feet, you can still pour the 4 feet and then slide down the top 5 foot piece, pour 4 again and then 2. What I was thinking was that if you drop a balloon full of water from 5 feet, it breaks but at 10' high, it hits with more pressure, and even more as you go higher. As water does not compress, the physics of anything hitting with more speed is fairly simple. Getting hit with a grasshopper when standing still is a whole lot different on a motorcycle at 60 mph.

As to wall thickness, where I am, main floor ICF is rare, not common, and acceptance is neither rapid nor assumed.
These may not necessarily be expensive homes. We are shooting for EnergyStar rating at the least expense. For example, what would Habitat design?

There is no linear cost comparison between a 4 and 6" wall (ie: 50% more concrete) and I haven't factored in taper top forms, 10% upcharge for SCC and possibly the increased rebar size. While it will be up to my engineer to determine those criteria, I am just focusing on this one factor. Increased wall thickness means more labor and materials for build outs, jam extensions, and the like so thicker walls come with more price and not everyone appreciates those costs.

I opened the first inspection business for home buyers in my province (30 years ago) when people were asking me "What in the world do I need that for?" Reality and perception changes require experience, time and education.

My first reaction to 4" walls was, "NO WAY!" I've since examined it and it looks OK by the numbers.
But it's very limiting by code and performance. A short wall is much better than wood. But due to its brittle nature, it is much less forgiving to high stresses invoked by tall walls. If you rely on reinforcing, it's still limiting because of its short "d" distance (the distance from exterior to the center of the rebar). And as height goes up, the load increases, and the stresses increase by the square.
I'm slow; I don't follow your description. What is TF? Is this an elevated slab? A 4" wall has additional issues w/ a concrete floor. I'll comment on that once I understand. Sorry.
I would NOT, under ANY circumstances, put a horizontal joint in a 4" wall. There is a recent thread ("How high to pour", or some such) where we went into that. Read that and if you have questions, go ahead.
Nothing wrong with SCC but I wouldn't. No real benefit over a good grout mix. I'd use a pea-gravel mix but only if you can get good 3/8" aggregate in your area. Maybe 1/2" if you can get it in w/o honeycomb. Nothing larger. And you can easily get 4500psi (sorry, don't know the conversion) out of that mix.
OK, "FOCUSED". We sometimes. There are some of us that get on here and offer free advice and answer a lot of questions. I was on here at the inception of this forum (though I got bumped off at some time when format was changed) and there are a lot of people on here whom I "know", though I haven't met them. We banter or like each other's discussions and sometimes get lost. If that happens, simply push it back on track, or even post a new thread. But give us old farts some latitude. It is, after all, free advice. Not many places you can get something that valueable for free these days.

Thanks Jerry.

Oops, my bad. The ICF system is from TF Vertical ( http://tfinsulatedconcreteforms.com ) and the horizontal joint is just a split in the vertical foam. (I often hear it referred to as TF, so I did the "assume" thing. Splitting the foam is a perk of this system not shared by any of the block systems.) It is a bit like opening up a sash window to pour the lower 4', and then lowering it to pour above that opening. It is shown much more clearly in diagrams on their web site.)

The SCC in a 4" cavity idea seems to lessen or eliminate the honeycombing and requires less concrete as well as no consolidation in that narrow space. My initial thought is that this combination solves several issues at once. However, that is the point of asking people like yourself with the technical skills that I don't have.

I know it is only an educated guess on your behalf, but might you know how high the 4" wall (as I describe) could be? I am not sure if a "tall wall" means 12' or 18' ... or more.

PS: My grey cells have been firing quite effectively for 62 years ... so I sometimes ask for the same indulgence ...

Thanx again for you comments. I do appreciate them.

SCC is good stuff, so whatever you're comfortable with. as far as consolidation in the 4", you'll have to get the installers to chime in. I've never actually seen it installed.
"Tall" will mean different things depending on the application. That's where you have to hire an engineer to design anything beyond what the mfr's, or the prescriptive methods say. And remember that the tables only apply to the conditions and situations that they describe.

Thanks again Jerry. As you can see, responses (so far) are pretty sparse. Yes, I have an engineer meeting on Tuesday but I like to do my background research first. Ultimately, it will be his design, regardless of what I find out. I have no knowledge of this prescriptive method so I will look for info on that.

One of the joys of SCC is how it flows around so nicely. One of the downsides is that it also flows out equally well. So suppose you have pourd 4' of wall and a blowout occurs at the 2' level; everything above 2' will exit via the blowout (unless you can somehow stem the flow. When you meet with your engineer why don't the two of you look at Helix steel fibers (http://www.helixsteel.com/). We have successfully used Helix many times in 4" walls with 3/4" aggregate and 3,000 PSI concrete. FM

Thanx FM. I'll definitely mention it to him. I'm trying to trade off the vibrating for the SCC.

RU saying to use normal concrete, with a 5 slump and not SCC and then I would need to vibrate?

Hi Full ICF. The only 4" forms we've used have been NUDURA. We use 5"-6" slump, 3/4" aggregate, 3,000 PSI concrete, vibrated with a 1" pencil vibrator; no problems ever. If you go this way (away from SCC) you'll save $$ and have a fine end product. If there is no NUDURA distributor near you, use a different form & go with the manufacturer's specs. FM

I am a NuDura installer as well, but never used the 4" main floor walls. Actually, SCC is only 10% more per yard so the tradeoff for the lack of vibrating is not bad. I may be in a situation where skilled (volunteer) people are at a premium. Our available SCC jumps from 20mpa (3000 PSI) to 50-60mpa (not sure what that is in PSI ... but it would be large).

How high have you gone with 4" walls (as encountered in gable ends with vaulted ceilings?

Hello Full. I'm not an installer; those days are behind me. But I have worked with a lot of forms, most recently NUDURA. We never did anything tall with 4" forms, I think 5 or 6 courses at most. But height isn't any sort of issue IMHO. Gables are no problems once we learned how to do them. FM

I'm not sure what is meant exactly by main floor walls -- but I've seen multiple story 4" here -- not very often however.

Texas:

Foundation, then main floor (grade level) exterior walls on top of that. (No Second floor walls for this project.)

.

We have poured 4" nominal ( 3 1/2" actual cavity)  TF System Walls for Main floors in heights up to 12ft. Several lifts (3) of course.

No problems whatsoever incurred. We used the TF System recommended slump. As a matter of fact, on one job we were not able to get the pumper hose to a far corner, so we had to blow the concrete against a plywood board and let it drop in to the cavity. That corner was done in two lifts. 

Where available, we poured through window / door openings first to bring up the height of the concrete, before pouring from the top. It is more difficult to bring the hose in, however, I like to use the flexible hose ends that you can squeeze a bit to control the flow.

On hot day pours, we generally use a Superplasticizer to make it flow a bit better. We do not however, go with a 'soupy', high-slump mix.