We are in the process of building an ICF home (using Integraspec blocks), and I have a question about attaching siding. We are using Hardi siding with a five inch exposure. Apparently, the embedded furring strips in the Integraspec blocks do not extend to the full width of the block (top and bottom), so every five courses or so there is nothing to screw the siding into. So, we are using small Simpson gusset plates wherever the strips are missing. Anyone run into this before? Are there better ways? Do other block manufacturers hold the furring strips back the same way? It just seems very time consuming. In retrospec, it seems like it would have been worth it to strap the whole house with some sort of vertical strapping first. I'd be interested in other builders experiences.

Also, what have people done with out-of-plumb or bulging walls? I have a daylight basement, and the exterior walls are up to 1" out of plumb in places. I'll just have to live with it on the exterior, but I wanted to finish off the inside and didn't want to run into problems when installing cabinets and things like that. Do I just take a planer to it? Fur out the entire wall? Again, ideas would be appreciated.

Maine Builder,

Your siding issue is common to ICF blocks. Some manufacturers make blocks with full length webs. The other way to avoid this is look at the system you use and adjust your reveal to match the system you are using. The modules of the manufacturers vary but most are between 12 and 16 inchs in height. With a 12" system you could use a 4" or 6" reveal aleveate the issue. The Simpson gusset system works also.

As for your bulging walls. Rasp off the bulge with an EPS rasp. This should make life easier. Ifd you need to take more foam off than covers the webs then furring the walls is the best option. As far as the cabinets go I am very conservative in this area. I know people who attach cabinets directly to the webs, ther are otrhers that will sheet the wall behind the cabinets with ply wood, I attach a nailer to the concrete.

ICF Contractor.

Thanks very much for the info. I'll probably just fur out the entire wall where it's the worst. That will probably be the quickest.

As for the siding, we'll continue using the gussets. But this brings up a pretty good point about ICF construction in general: The manufacturers and salesmen don't do a really great job of filling builders in on this stuff from the beginning. I know if I had asked the ICF salesman one year ago if there were any special considerations when it came to siding, he wouold have said "Absolutely not. Other than needing to screw it on instead of nailing it up, it will look the same as a stick built". I never dreamed that the nailers didn't extend through the block, and now I have to go out and buy $300 worth of metal plates.

All in all though, I like the ICF concept. We can't wait to move in.

remember now too, when it comes to sheetrocking you'll possibly have the same trouble.. let the rockers know where the voids are (they'll find them anyway I guess, maybe you're doing the rocking?) and.. I hope when you're doing the baseboards that they don't fall on the voids. A good note.. you're electrician might like not having to cut through the webbing and will be able to use the voids to run the wires.

Our electrician has worked with ICF before, and he didn't seem too bothered by it (or maybe he just made up for it in his quote :) ). The voids will definitely work to his advantage though.

I am not so concerned about the sheetrock. Since the strips are 8" apart left to right, couldn't the rock float six inches or so if it had to, especially since there is solid foam underneath it? We will be using 5/8" rock, in case that's relevent. The vertical voids should be less of a problem, right? Or do I need to be concerned?

Unfortunately the bow in the wall is an instulation problem probably caused by the bracing being screwed tight to the wall and not allowing the forms to settle properly.

As for the siding issue I agree with ICF contractor adjust your reveal a little to allow for the gap in the tie, or just move the starter down a little so that you will not line up with any of the vacant areas.

[quote]I am not so concerned about the sheetrock. Since the strips are 8" apart left to right, couldn't the rock float six inches or so if it had to, especially since there is solid foam underneath it? We will be using 5/8" rock, in case that's relevent. The vertical voids should be less of a problem, right? Or do I need to be concerned?[/quote]

No, no reason to be concerned, the sheetrock will float it's just that if they put a screw there it will be like missing a stud in a framed wall... a nuisance is all. Why go with 5/8 rock on the walls? + on interior walls 1/2" will make your standard door frames/jambs fit better. My recommendation would be to go with 1/2" on the walls, save the 5/8 for the ceiling.

Unfortunately, we didn't run into this until the siding was up a few courses. And, it is a pretty complex design, and it wouldn't be feasible to adjust the courses so they missed these voids. It is just one of those "gotcha's" that I'll work around.

I have seen a couple of different metal strapping systems advertised. I plan on building more ICF homes, so would that be something to consider in the future? Or, if I chose a block that had continuous furring strips, would I be locking myself into a narrow selection of manufacturers?


The 5/8" was suggested by the drywall contractor. The interior framing will most likely be steel studding, and he said the 25% added thickness would give the interior walls a lot more strength, considering that we will have 10' and 11' ceilings. I'll suggest to him that 1/2" would definitely be sufficient on the ICF walls though.

We use a block with the spaced tie all the time and just adjust so we do not hit the vacant area, The metal strap will work but it does increase the cost, and in most forms I have seen a 1 1/2" adjustment to the starter row will do the trick.

If you choose to look at a wall system that has full length ties about the only people that will have a problem with it is the electrician, our electrician runs everything from thre top down or from the bottom up, occasionally he will run vertical from one box to the next like in the kitchen area and then the issue of having a tie to cut through can be a problem depending on your electricians experience with ICF ties.

All and all it is like I tell my students in ICF class that foam is freindly so you have to decide what will work best for you in the application you have, and the only form you may have a major issue with is the ones that use a metal tie they do not cut well at all.

The spacing could have been a better thought out process with other forms that wouldn't have caused this problem? i.e the average block out there would consist of 7 courses for a 9"4" wall instead of 9 courses for Integra i.e. creating more metal tie bridging issues. All have some sort of advantages, even thou you choose the best knock down form available it may not have been the best choice of your situation. Any form with a non continuous tie may work for someones situation depending on the lap repeat. A continuous tie doesn't always fix this situation with those that have them. Most continuous tie forms have metal which impedes the electrical installation. This is a good reason why most ICF dealers should sell more than one b rand to meet specific situations.

Dave

I guess my problem with ICF is that this was never brought up as an issue up front. There is nothing in the literature, nothing on the Integraspec web site, and nothing brought up by the Integraspec salesman about how some siding applications might be a problem. And if you go to a home show and look at all of the ICF products and ask what you have to do differntly with ICF, they will tell you that there are no limitations.

I am using a 5" lap (perfect for this size of a house) and it just won't matter where I start the first course. Because 5" is not a multiple of 12", I am going to hit a void sooner or later. I suppose I could have gone with a 4" lap, but then my material cost and labor would go up 25%. I could have gone with a 6" lap, but that wouldn't look as nice and would have the appeance of the old style fiberboard. I just assumed I could side the house with any lap I wanted. I was stunned to see that the plastiic furring didn't extend to the edges, and I still can't figure out why it is held back.

It's no big deal. I just don't get why this info isn't up front so the installers can bid it properly. But I guess if anyone sees this thread during a Google search, they'll have fair warning. :)

The number of forms that have a full  height tie are far out numbered by forms that have a "gap" between courses.   It's to bad that your were not fully informed by the sales person, but in his defence it is in their literature and installation manual.   always better to fully research your intended product.  It can save you some headaches in the future. 

In regards to the 5/8" rock, many times my drywaller will use 1/2" fc, which is a stiffer product. It's also harder to cut, but then so is 5/8".