Any experience with ICF homes?

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ShockedOneinAZsun

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Yuma, Arizona
I was presented with a set of prints for an ICF home. (Insulated with Concrete and Foam). The walls are made up with a concrete center, plastic studs, and foam insulation on both sides. The walls are 12" thick.

The proposed method of installation was to cut out the foam and insert a 4 Sq, metal box with a mudring whereever a device goes, then use a chain saw to cut a 2 1/2" groove from one device to another, then install MC cable. I was told by the contractor that the groove would be tight enough, and it would be replaced by foam, that I would not even have to drill for, or install supports for the cable.

Has anyone done one of these homes, and if so, what are the pitfalls in bidding and doing this work?
 
I wired one of these houses a couple of years ago. it was a real pain in the XXXX . we were able to use romex /NMB and plastic boxes. we too used a Electric chain saw to cut out foam. we had to support NMB runs per the nec. . Luckally I bid the job very high and made some money.

I can tell you I never want to one of these again.
best bet is to talk to you local Inspector to get his/ her input as to what they would want to see on the Electrical. we had to reapair the foam where we cut it out it took about a case of expanding foam.
good luck with your project.
 
We've done quite a few and they're not that bad as long as you have conventional wood floor joists and rafters. We use NM, 1900's, mudrings, 1/2 or 3/4 EMT with plastic bushings at the top. We also use a "hot-knife" instead of a chainsaw. Way less mess and cuts through the foam like butter. Just vertical drops wherever you need an outlet or switchbox.
 
blue spark said:
We've done quite a few and they're not that bad as long as you have conventional wood floor joists and rafters. We use NM, 1900's, mudrings, 1/2 or 3/4 EMT with plastic bushings at the top. We also use a "hot-knife" instead of a chainsaw. Way less mess and cuts through the foam like butter. Just vertical drops wherever you need an outlet or switchbox.
Click to expand...

Okay, I know your name isn't "Wikpedia" of "Google", so I hope you don't mind if I use you for research.

01. What region are you from?
02. I am not familiar with what you mean by "1900's".
03. I assume you use the EMT as risers, but are you running the NM through it?
04. What kind of "hot knife" is it, and how wide of a gap does it cut? And you say you don't do horizontal cuts, only vertical for drops?
05. Do you have any photographs you can post?
 
ShockedOneinAZsun said:
Okay, I know your name isn't "Wikpedia" of "Google", so I hope you don't mind if I use you for research.

01. What region are you from?
02. I am not familiar with what you mean by "1900's".
03. I assume you use the EMT as risers, but are you running the NM through it?
04. What kind of "hot knife" is it, and how wide of a gap does it cut? And you say you don't do horizontal cuts, only vertical for drops?
05. Do you have any photographs you can post?
Click to expand...


1900's are 4" square boxes
emt with bushings is probably protection for NM cable sleeved
good luck on the hot knife
 
ShockedOneinAZsun said:
Okay, I know your name isn't "Wikpedia" of "Google", so I hope you don't mind if I use you for research.

01. What region are you from?
02. I am not familiar with what you mean by "1900's".
03. I assume you use the EMT as risers, but are you running the NM through it?
04. What kind of "hot knife" is it, and how wide of a gap does it cut? And you say you don't do horizontal cuts, only vertical for drops?
05. Do you have any photographs you can post?
Click to expand...
1- Northern MN
2- 4 Square Box (sorry about that)
3- Yes, nm through the risers as protection
4- It's an electric gadget which has blades you can set the depth and width on. It also has a 4 square cut-out jig. It uses heat to melt the foam. We just do vertical drops because cutting through the plastic nailers is a pain.
5. Sorry no photos.
 
There are many companies marketing concrete filled foam cells for walls. Some inner concrete cells are roundish and some are flat. The round make it difficult to mount boxes to. With both you need to calculate the distance from concrete to finished wall. Just dont stick out too far with a metal mud ring. With the round it changes all the time. ( Some have plastic strips on the outside for mounting boxes. ) On my first one the GC said he would get me a hot knife to use. Then he found out the cheapie was 100.00 and the right one about a 1000.00. After five minutes of the useless knife I got my 3 1/2 HP Bosch VS router and a 5" x 1/2" straight router bit, set my depth and quickly atached a guide strip to the foam and just routed my path. Very clean slot. Down side is white foam shaving's everywhere but it works.
If a home would go for 5,000.00 the foam would add about 2,000.00. I hate them.
 
I seem to recall one of these on a TV show. They actually had channels in the foam for running wires. Still had to do some hot knife cutting of the foam, and then back filling where the foam was removed, but seemed like a pretty simple installation.

Why would the foam itself not be considered support? Once you foam around the NM it is never going anywhere.
 
Before I became an electrician, i worked in construction, and every house we built was an ICF home. When it came time to wire the boss' house(also an ICF home) the hired electrician allowed me to help.(Which how I became interested in being an electrician.) We used plastic boxes an romex. Had a hot knife and it went to the crapper. Found out that a jig saw had just the right depth of cut and became very easy to mark out your box and zip it out with a jig saw. Same thing for a wire chase to loop receps and switches. We used Arxx and Logix brand forms, which have flat innner and outer walls. Also note that the plastic boxes we used matched the depth of the foam plus about 3/8". Worked out perfect for 1/2" rock. On these particular brand of forms there were plastic ribs(studs) every 8" vertically. But on every horizontal joint of the block there is about a 1" space where the ribs don't meet, and this works perfect for making a wire chase. The only snag we found was when you get to 3 and 4 gang boxes, the depth of the box changes and we had to fur out the opening with 3/4" thick lumber. Boxes were all screwed on with Tapcons right through the back of the box, if your opening is cut relatively precise, the box will fit perfect and not wobble or twist. It also works best to try and take your home runs through an interior wall, this way you dont have to try and fish down the foam and come out the rim joist in the basement or overhead. Best trick for doing that(and you will for phone/cable) is use a long auger bit and make a hard angle through the rim joist and bore up into the foam and you should be close to reaching the notch made leaving your box. Supporting wire is a little tricky, but if one uses a hot knife or jig saw like we did, you can save what you notch out and tuck it back in once the wire is ran. Hope some of this helps, sorry to make it so long.
 
I wired those houses in the early 90's in florida. I used electric charcoal lighter to do the cutting. used rx. Didn't have to replace the foam.
 
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