At least I now know, having sweated through an ICF build in two days of 85F plus heat.  There ain't no way you can do it with Logix, if your foundation has a few simple ins and outs for corners.

You know those tables in the ICF how-to books, the ones that give you preferred wall dimensions for their blocks of various core dimensions?

Here is how it goes with Logix 6.25" core, 11.75 overall thickness.  I'll just give you the numbers at about 8 feet.  Modular number, which is your web spacing, is 8".

Outside-outside, 8'-0"

Inside-outside, 7'-0 1/4"

See the problem?  If not, draw yourself a rectangle, 24' x 16'.  Now add a rectangular bumpout of 8'-0" width, bumped out 7'-0 1/4", centered on one of the 24' walls.

See the problem now?  Your inside-to-outside run on either side of the 8'-0" bumpout is 8'-0".  You know from the tables that if you shift your bumpout over 3 3/4", your short-side inside to outside will be an OK 7'-8 1/4", but your other-side run from bumpout inside corner to the far outside will be 8'-3 3/4".  There is no way you can do it with Logix.  Total bust!

How could those Logix product engineers get it so wrong?  Any rectangular bumpout along an outside wall is a bust.

They all say, "design your building around the ICF modularities," but with Logix 6.25 core, you had better keep it real simple.  Like a rectangle.

I wish we had used Amvic product.  The attached pic shows plan dimensions using Amvic modularity.  You cannot use Logix dimension tables and design a footprint within 6 inches of this layout, and make it "close."

Let's look at this Logix "no logic" another way.

Think again about the simple rectangle with the rectangular bumpout.  The side opposite the one with the bumpout has one long dimension, outside corner to outside corner.  That dimension has to equal the opposite side's three dimensions: outside to inside, the bump's outside to outside, and the remaining run of inside to outside.

Logix's modular figures for out to out are all even inches, no fractions.  Their inside to outside figures all end in 1/4".  So, any sum of an in-out, out-out, and in-out, as on the bumpout side, ends in 1/2". 

As in 1/4 + zero + 1/4 = 1/2. 

With the plain side at even inches, and the bumpout side at something-and-a-half, you've got a 1/2" bust.  Enjoy having your buildings starting off 1/2" out of square?  I don't.

Logix blocks will mate when cut on 1" modules (the blocks are scored this way), but not if cut anywhere in between the scores.

Bust.

Bye-bye, Logix.

First off why would you have a bump out that is 7' 1/4" in-out?? Second I dont see your point in moving the bump out 3 3/4" one way, of course one side is going to be shorter and the other longer then 8'!! So the long side would have to get a short cut piece of block!? Big deal!

"There is no way you can do it with Logix. Total bust!"

Yes you can, its just that your interlocks won't line up and youll have to shave some of the knobs where the rows overlap. Just like you would have to with any other icf block.


You as the builder are responsible for making your building square. Like any other icf block there are dimensional tolerances. Logix's forms have a tolerance of +/- 1/8" straight from the molds. The 1/4" deviation that you are reading in the manual for the inside to outside demensions is more then likely taking this tolerance into account.

If that 1/4" in-out figure was published as an even 8' then you would have no argument. On paper is one thing, but what happens on the job is another.

"Logix blocks will mate when cut on 1" modules (the blocks are scored this way), but not if cut anywhere in between the scores."

I don't see your justification. Yes your right but other blocks have the exact same problem. On any ICF job your going to run into this problem.

Logix is a great product, probably one of the best Icf's out there.

Gene,

I am a contractor that has hundreds of builds under my belt. I have used both Logix and Amvic. Your issue is really not an issue and your local distributor should be able to quickly and easily get you on the right track.

This is one of my biggest gripes about our industry, that sales people tell homeowners that if you can stack Lego’s you can build your home. The truth is if you can stack Lego’s you can stack Lego’s. This is not a prequalification to building what is considered by most to be your most valuable asset. I feel that this is a very simple way to build and is easy to teach to people but if you don't have any building experience then you can not expect to do it well or be perfect or fast the first time you do it. I liken it to having a family member with a brain tumor and I go out and pick up a book and a "do it yourself brain surgery kit". Then I go home and read the book, lay my family member down, perform brain surgery, and expect a great result. Ain't gonna happen.

Now building is not brain surgery but it is complicated and should be approach as such. Many homeowners who have some building experience can be successful with quality guidance from an experienced contractor. Your problem is not the product you have because it is an excellent product and your idea that Amvic is all that and a bag of chips is not completely accurate. With the Amvic interlock your problem would only be exacerbated with your current measurements. It looks like you could have used some quality advice back in the planning stage but all is not lost.

The simple answer is start at your corners and build to the center of your wall. This will leave an uninterlocked area in each wall but this is easily rectified with some cleating with strips of plywood or 1X4s. If you have widows or doors, build to the middle of a window or door to minimize your cleating.

You can email me if you have questions on this methd of building with ICF. [email protected]

IC Contractor

I tried to follow the "bump-out" dimensional query above, and gave up?? It doesn't matter which block you use, it only matters how you establish the dimensional requirements of the project to mate with the product at hand!! Taking dimensional data from a generic book, and then expecting that to coorelate to a specific product would be unfair to any manufacturer!

This is not a Logix problem(which I do not use), it is strickly a misunderstanding of sales to end user!

Once again...Where is your field technical support, which should have been available in the beginning? As a design/build contractor, I always have the option of on-the-fly changes in dimensions, knowing what it may or may not impact down the road. Each block out there has little quirks in assembly......work your corners toward the middle, and spend your time making incremental adjustments under and above openings!

In a perfect world, there would be zero cuts, because EVERYTHING would be uncut, including window and door placement, window and door heights, etc.! That just isn't very practical!

Mr. Eggert, let me ask a simple question.

Do you use the "preferred wall dimensions" tables as documented by your ICF manufacturer, when designing your footprints?  In other words, do you adjust your building dimensions to fit to an ICF modular scheme?

We got tech support, my partner and our helper went to the class, we understand clearly how to cut blocks and put a foundation together, and are always ready to change dimensions on the fly. 

Gene,

I cannot speak for Jim but rarely do the buildings that we build fit the modules perfectly. It is our opinion that we need to build the building as designed and make the form fit the structure not the other way around. When pouring conventional 1 1/8" panels the same conditions exist we must cut and adjust the panels to fit the structure. The architectual plans should trump the building material module and the engineering trumps the architectual. That is the hierarchy of things.

And as for the "preferred wall dimensions". Take any manufacturer and their product, actually lay out the product, and you will be in for a good laugh in most cases...or maybe a possible cry.

When I consult with designers and architects we sometimes will take the product and lay it out, ziptie it, and see what is really practical. This gives the design professionals an excellent spacial viewpoint of the product.

Hope this helps

ICF Contractor

Thanks.  I'm the engineer, and I trumped the plans, and the plans trumped the Logix, so we made out OK.

Having not built with any ICF before, we weren't careful with the orientation of some of the cut blocks, and thus have rib misalignment, which will cause us a little bit of trouble at sheetrock time.

As anyone would when building with ICF blocks, we ran into the usual raft of size imprecisions, which caused us to make on-the-fly tweaks in the layout.

My partners were instructed in the half-day class they attended (I was out of town), to build the perimeter in one direction or another, setting corners first, working from an end to a corner, then cutting as required adjacent to the "coming to it" corner.

I thought that was incorrect and I told them so.  My information had make-up cuts away from corners, not up tight to corner blocks.

All things considered, when doing the next ICF job, I'll want Amvic instead of the Logix.  The price is about the same, we'll save a tiny bit on 'crete because of the 6.00 core versus the 6.25 Logix core, and best of all, I now know how to design so we'll have rib alignment everywhere.  The Amvic, with ribs at 6" versus 8" with Logix, allows me to come closer to the "desired first cut at it" footprint, and, at least on paper, the modularity works.

Gene,

When designing your next building keep in mind that the modularity of Amvic is closer to 2 inches. There are things you will find out that you won't like about Amvic. I personally dislike the webs that are so flimsy, they don't hold a screw worth a darn. Also the whole corner dowelling is a good concept but I have had problems with the corners holding trim and such. On the plus side it is a strong block and can handle a 2" vibrator with a 6" slump without a problem, and I am on the fence about the reversable block.

Also if you just forget about the module and start from the corners and build to a center joint all of your webs will line up for the purpose of sheetrock and siding. This, I have found, makes it much easier for the subsequent subs and brings down your costs of your subs.

ICF Contractor

Gene,

One other thing. A half day class??? If this is the standard manufacturer's class they have a half day of advertising in the class. When we have a class we have extended them to 2 days so we actually stack and pour out a small structure. When we are done we feel our students have a good concept how to do the layout, stacking the block, bucks, lintels, special circumstances, pouring, and consolidation. Once we are done pouring the building we hold class on how to side, wire, rock, and frame to ICF.

ICF Contractor

I'm very interested in one of these classes. Where do I look for times dates places?

Gene: This is only your first, and you have now recognized the inherant difficulties with ICF's.
The dimensional problems you encountered apply to all the products out there. None are perfect.
Doesn't matter the brand, you have to have a strategy in place beforehand.
Now you do.

I've been to at least 4 different "courses" and found the majority to be given by "sales" guys. LOL
The learning curve is 3.
Keep at it, by #4 you'll have it dialed. Cheers.

Thanks, Eric.  Here are a couple pics of the next one.  Slightly scaled down from the one we just did, and modified to accommodate Amvic wall runs and "theoretical" modularity, all cut "infill" blocks are "on module" for the product, which is 6".

Something we learned from the last one, which I thought we might try on the next, is this.  We use a Pacific Laser Systems PLS5 3-beam laser to lay out for the wall lines and corners, marking out on the footings.  Next time we might do it late in the day on day one, set the corner blocks in place everywhere, use the laser to check blocks for level, shim where required, and glue down all the corners.  Just the corners.

The following a.m., with the work points fixed, we'll work in from the corners, hoping the midwall "fills" come on the numbers, but we'll take what we get, and cut EPS nub interlocks if we have to.

I use Sketchup to build a foundation model such as this in fifteen minutes or so, using a library of component blocks I modeled earlier.  The color codes show me the different sizes of cut "infill" blocks.

Maintaining the nub or block interlock, and revising ( your dimensions to suit) will allow you to build with less frustration and more speed.
For what it's worth:
We chalk our layout on the footings in red, using a theodolite (transit) .
We tag all corners with a short concrete nail and red flagging tape.
Layup 3 or 4 courses and then spend 30 minutes levelling and shimming the works.
Next we glue down with foam and continue the build, to 5 or 6 ft in height, depending on wind conditions.
Then we attach scaffold system and finish.

Most manufactures have "odd" dimensional outside corners and 45's. This thows off any possibility of maintaining Architectural freedom.
Blame the patternmakers and the CNC guys who built the molds. Nobody told them, I guess.LOL

Gene: That is an excellent sketching tool !
Will it dimension fractions?

Sure, it will dimension to show fractions.  Right to the 64th, if you set it to that precision.

There were no fractions in the model for the overall wall runs.  The blocks that are cut, that end at the no-corner ends, are fractional in length.

Gene
I think you already answered your question in that you determined also to work to the middle. When I first started I worked from one end to the other, usually two courses at a time, and spent an inordinate amount of time securing the cut area for the pour!

Do I spec out my buildings for module lengths?? To some extent yes, but I don't live and die by it. If there is a dimensional issue on one wall, the same thing is somewhere on the opposite wall. Keeping in mind that a typical wall is 7-9 courses, that amount of cuts per wall per floor is negliable to most installers!

I also use Sketchup, but you have a better handle on it's use for block layout than I do! I congradulate you on your color and layout prowness!!

Having worked with several different blocks I find it easier to set the corner, then work to the middle.  I lay out the doors and windows on the slab if possible.  I try to have the "stack Joint" fall in a door or window.  Much less cutting is needed.  I mark it so it hopefully doesn't get moved during the stack. If you have a multi-story build it will follow to the top.

I agree with Tom and Jim, when we do our training classes we always instruct to splice in the middle or at an opening to reduce the number of forms that need to be cut. Although we use a form that is ship lap so we do not have the issue of lining up the nubs it is still important to get the max amount of tie line up to make the future more efficient, such as sheet rock and siding.

Let us take a look at conventional framing what happens when you have an odd dimension there, lets face it you cut an additional stud and install it I for one do not see the difference between doing that and cutting the forms and again if you do this at an opening it reduces the number of cuts being made.

Ok so now we know that in the design of a structure the math does not always work out and we have to use the old noggin to figure out the adjustment.

Here is an oldie but a good point on math.
three hunters rent a cabin for a day the charge is $30 they each put in $10, the land lord realizes after the fact that they where running a discount that day and the cost of the cabin was only $25 dollars. The land lord has his clerk take $5 out of the till to reurn to the hunters, the clerk realizes that there is three hunters and that $5 does not divide into three very well so he gives each of the hunters $1 dollar back and keeps $2 for his tip. Now each of the hunters paid only $9 for the room and the clerk took $2 as the tip. do the math $9X3= $27+$2 for the clerk = $29 what happened to the other $1

Here it is, yesterday at 2 p.m., all built, despite our little argument about modularity.  I left while the others ran additional bracing, glued more cuts, added scabs, etc.  We began at 8 a.m. with the pour today, and the pumper pulled out at 10:30.  No problemo.

I tried to explain to my pard today how it makes no diff whether you run from corner to corner laying block, doing the makeup cuts adjacent the "go to" corner, or whether you build into the center from corners, inserting the makeup cuts at center of wall run.  You'll end up with a stack-up of sawcuts offset by a bond run length, either way.

Can you all explain your preference for having the cuts midspan of walls, rather than up into corners?