That requires very long bolts to attach something heavy like a sunshade. (not to mention the bolts bending)

This may not apply to any particular application, but let's look at the math regarding attaching things to foam. Say you dig a 2" deep channel into thick 15 psi foam and push a 10' 2x4 (actual) in it (no bolts or screws). It will support ~3600 pounds (downward) before the foam fails. More if you use glue. ~7200 pounds to pull it out horizontally (with glue). Expect similarly large numbers when gluing OSB or plywood to a foam wall.

High speeds and high torque is the problem.

True dat. It was hard to keep the boys on my job site to get that. Real men like it hard and fast.

The screw heads only pulled through the wood during testing. I have never heard of it happening on a Polycrete wall in the real world.

If the point of failure is the head pulling through, the entire system would be improved if someone made a specific screw with bigger heads.

7200 pounds to pull it out horizontally (with glue).

Glue is nice, but I've become adept with wedge type expansion anchors. Ain't none of my stuff coming out.

A forum like this one can be very helpful except when it becomes populated by posters who have no technical or practical experience/expertise promoting themselves as knowledgeable. On separate topic, ICFHybrid, while you make a good point about a specific screw type, the screw head pulled out of the wood at 400 lbs of shear -- that's on one screw. I think if that presents a problem in the real world, you probably don't have enough screws in whatever you're screwing to the wall... Just sayin'

I think if that presents a problem in the real world,

I'm not sure it's a "problem" so much as an opportunity to make something better. When people look at things and say "I can make that better", something usually moves forward. That can lead to all kinds of good things.

Posted By NewHoosier on 26 Nov 2014 02:03 AM

The reason I ask is that I obviously want to some sort of wall in front of the insulation. For me such a wall would serve two or even three purposes. It just looks a whole lot better, a space to put wiring (electric, network, TV, etc) in. I might even fill it with some cheap glass fiber bats for a few extra R.

My point is that with adding that extra wall I create a distance between the furring strips and the outside of my interior wall. And by doing that the problem the furring strips fixed is reintroduced.
I think that's a bit advantage of cavity wall. They are worry free. You can hang heavy stuff where you like. Put all sorts of piping in it without having to worry about anything.

Is there any disadvantage to creating a wood-framed hollow cavity between the ICF and the interior drywall? Obviously it cuts in to your interior space, or causes you to make the house footprint bigger. Maybe not completely hollow, e.g. throw some fiberglass bats or cellulose in there, as NewHoosier suggested. But the purpose is strictly for convenience, i.e. virtually all the thermal requirements are handled by the ICF. The wood-framed wall allows for familiar/traditional mounting of things like kitchen cabinets. Also, I would think wiring would get much easier, particularly if any changes to the wiring in the future are desired. For example, in my case, no matter how much Cat6 I run, I always find a need for more. How does one pull extra wires in a "pure" ICF wall?

PROS
A wall needs finishing anyway. My choice wouldn't be drywall. Much too fragile. But that's personal of course.
It adds more insulation which is never a bad thing. You could use a less thick ICF because you add insulation in a that way.
It's more convenient for cabinets and wiring as you wrote. Not just rewiring BTW. Putting wiring in ICF or any other insulation material means a thermal break. Should be avoid imo.

CONS
Wall may get to thick and windows start looking like tunnels.
Extra space needed.


Cat 6... I bet your house a separate computer room like mine :-)
Tip#1 Cat 7 is cheap.
Tip#2 WiFi antennas in the walls/ceiling. Looks better that way. It cuts their range but who says you can have just one :-)

About running extra wire in an existing wall. I don't know how it's called in English:
http://www.laminaatwarenhuis.nl/webshopImages/Plinten%20en%20Accessoires%20Kronotex%20Plint.jpg

There are quite fancy types with have enough space to run a few wires. Here it's mainly used for telephone, network or coax because electric wiring must be in piping and those are too thick. Well officially :-)

Well you shouldn't have any trouble attaching most reasonable structure to the inside of the ICF wall using the installed form crossties. The form crossties are also spaced more frequently, typically every 8" as opposed to 24" for a typical stud wall. As mentioned anything structural of course needs to go to concrete. The addition of an interior wood frame wall inside the ICF will make the wiring just like any other stick built wall. The internal attachments also become like any other stick built wall(for better or worse). It also simplifies any wiring transition you may need to make across a floor diaphram along the outside wall say to get from a basement power panel to the switches and outlets in the exterior wall? The stickbuilt wall extends out over the floor attachment allowing you room to run wiring or plumbing up past the floor-wall attachment. Perhaps of more concern in your floorplan may be the seismic and environmental factors for the area you plan on building. One of these will control the wall structural requirements which will determine how close ANY openings can be to ANY corners, as well as the total area of openings in the walls...

Once the walls are built, the only way to run a new wire is down, across, and up. With ICF, you can cut the hole for the new outlet, cut a matching hole in the basement or crawlspace, then drop a red hot ball bearing into the foam in the upper opening. About 30 seconds later, it will drop into the lower opening. I wired much of my house this way to run wiring into the basement in external walls. If you are built on a slab, you'd have to do this from the attic instead. The one catch is if you have significant concrete oozing between the ICF forms. The ball won't burn through that.

I keep reading about hanging cabinets being easier to hang on a stud wall. Not true; ICF has plenty of places to attach things- more than studs, in fact. If it really has to be structural, drill into the concrete and use an anchor. I hung my full weight (200 lbs.) on a single screw driven into an ICF tie to test it out, and it held. Even ringed nails are pretty hard to pull out.

I don't like the tunnel effect of thick walls. There are several solutions. Windows can be mounted partially or fully inside, either splitting the depth, or creating a tunnel on the exterior. My solution was to create flared window returns, with a 45 degree angle on each side. We like the way it looks, and it lets in a lot more light.

jdebree,

If I would use interior framing I wouldn't use standard framing. It still requires planning, I fully admit that, but I would for example make very sure to have horizontal beams on the the correct height. Of course it depends on the height of the ceiling but I would say 1 yard from the ceiling.
It's personal but in my house there MUST be framing for various reasons:
- Convenient.
- I like a classic look, so my house will have lots of wood finishing inside. That has to be fasted.
- For cabinets
- Light stuff like painting/photo frame
- Wiring. I look at it this way. First I'm spending many hours on this forum to get advise for the perfect insulated house. A little while after the contractor done a perfect job I start cutting lots of insulation away for piping, wiring, boxes, bolts for fastening, etc. That sorta destroys the whole concept. I see only 2 ways around that. Framing and extra exterior insulation.

What was the deal with Romex and EPS? I remember reading that Romex could react to the EPS foam.

If possible, it's always best to minimize plumbing runs on the exterior ICF walls.

When the EPS is removed with a hot knife, can it be replaced back into the slot after the Romex is put in?

Posted By Lbear on 01 Jan 2015 05:52 PM
What was the deal with Romex and EPS? I remember reading that Romex could react to the EPS foam.

If possible, it's always best to minimize plumbing runs on the exterior ICF walls.

When the EPS is removed with a hot knife, can it be replaced back into the slot after the Romex is put in?

The concern was with the EPS foam leaching the plasticizers from the PVC jacket and insulation of the wiring.  As the plasticizers leave the PVC, it becomes brittle and can crack/break.  Romex brand SIMpull Type NM-B (non-metallic sheathed cable) has nylon incorporated into the outer jacket to make the wire slick and easy to pull.  The nylon is unaffected by the EPS and retains the plasticizers in the outer PVC jacket.  Also, the individual conductor PVC insulation has a thin nylon jacket over it as well.  This thin clear nylon jacket is easy to see when you strip the wire ends.  So, even if the outer jacket becomes brittle and cracks, the actual conductor insulation is protected by the nylon jacket.  Not all brands of home wiring have the nylon incorporated into the outer jacket, but every brand that I have worked with in recent years has the nylon over the individual conductors.  And that is what is important.  The outer jacket is primarily there to protect the inner conductors from damage during installation.  Once the wiring is installed and properly secured, the outer jacket doesn't serve much purpose.

Once you cut the slot in the foam with a hot knife to install the wiring, there is nothing to put back.  You only cut ~1/4" wide by ~2" deep groove.  The EPS is melted away.  After the wiring is installed, you come back and shoot some canned foam in the groove to insure the wire is held back away from the face of the foam at least 1-1/4" to keep drywall screws from accidentally penetrating the cable (electric code requirement).  But a hot knife isn't really the best tool for the job here.  All that I have used are painfully slow.  And if you have any cream seep into the joints between the ICF foam during the pour, this will block the hot knife as you try to cross the joint (it happens).  A hot knife is fine for cutting the foam out for the electrical boxes, but an electric chainsaw with a bolt through the bar near the tip to act as a depth gauge is much more productive for cutting the channels for the wire.  I picked up a brand new one on ebay for <$15.

The plastic ties will hold cabinets and most everything else in your house without an issue. arkie6 nailed the electric issue, hot knife for boxes, electric chainsaw with a depth stop for Romex.