ICF (Insulated concrete forms)

[cschmid]

when wiring ICF's is NMB allowed? How would we be able to classify NMB protected in Styrofoam? with the form only being 2" thick is it conceivable to say that in order to remain 1 1/4 inch's in Styrofoam you could do it as to never be exposed to the concrete? Just curious since it is new building method and not covered in the NEC that I have seen.

[cadpoint]

I looked for NM-B in 334. and that was not even listed. Someone straighten me out...
334.10 (B)(2)- ... not used ... where embedded in masonry,concrete, adobe fill or plaster.

Any one that been below the boarder and in the out back that's exactly what they do with there Adobe's... :roll:

[cschmid]

oops just NM sorry about the extra key must do better job of proofing.....

you know the wire you use everyday when you do residential, like the wire you get from HD, Lowe's, Menards...you know the wire home owners buy.

[jamesguy10]

I'm giving you the benefit of the doubt about your qualifications to perform electrical work, but if you dont understand the difference between NM and NMB than im wondering what sort of training and licensing you had...

[infinity]

I'm not sure that I understand the question. Do you want to run the NM cable within, in front of, or behind the Styrofoam? Also the 1 1/4" separation is from the edge of a framing member.

[Pierre C Belarge]

I'm giving you the benefit of the doubt about your qualifications to perform electrical work, but if you dont understand the difference between NM and NMB than im wondering what sort of training and licensing you had...


There are countless people in our industry who are good electricians or ECs that are unaware of what the B in NM stands for. Some actually would not even know what NM means, as "Romex" is the nomenclature they are accostumed to.

[cschmid]

A simple question of whether you can running NM in ICF's is code? degrades into cheap shots. wonderful good morning to you too... I make a good living doing this and have had one change order from the inspector in 20 yrs and It was not even my work and he made me fix something already installed by someone else. so snide remarks wont affect my pay or credibility with the inspectors here. so have a nice day and later on.

[stevenj76]

A simple question of whether you can run NM in ICF's is code?

What about UF-B?

Are you talking about the styrofoam blocks that go between pours? Or is this the insulation that goes underslab?

Will it go through the pour? Whats ever been wrong with smurf tube? That stuff is pretty cheap and allows for future flexibility like adding ckts.

[jtester]

I am currently having an ICF home built for myself. I believe I can use NM in the walls. It will have to be chased 1 1/4" into the wall pr provided with some type of mechanical protection. We build a lot of adobe around here, and NM isn't permitted in those walls, they are considered hygroscopic by nature.

Jim T

[mattsilkwood]

we recently did a resort that was like that. what we did was take a heat gun with a pencil tip and melt a groove into the foam, be carefull as this stuff melts QUICK. then just stuff your wire into the groove and cover it with clear packing tape. worked out really sweet. also your boxes will give just the right amount of reveal just take a sheet rock saw and cut the foam then anchor to the concrete.

[cschmid]

Good after noon I did do a typo last nite on the NMB I have discovered that being that specific with the wire, we would not look at the other aspects. Now I will tell you a scenario. Last year one of my co-workers a civil engineer built a new house and he had a ICF basement under it. These insulated concrete forms (ICF) are Styrofoam with plastic nailer built into the foam every 16 & 24 inch's. the nailer's are only 3/16 to 1/4 of an inch thick; depends on brand. He wired his in EMT and when the inspector inspected it, the inspector told him he could of saved some cash by using NM. I was shocked because the only way I can see being able to run nm is by cutting a grove in the foam and I do not see how foam provides protection from physical damage. if you cut a groove in wood you have to cover it with a steel plate. that would be impractical in foam. how would you secure it? romax staple in the foam, that does not sound like it would hold to me. I do not see any way of drilling it. So I was wondering what others have found working with it? I was also curious of if anyone here sat on a committee that has discussed this new building practice? I know it is catching on fast here and I can see real growth in that area of construction, especially in the commercial arena.

[cschmid]

I'm giving you the benefit of the doubt about your qualifications to perform electrical work, but if you dont understand the difference between NM and NMB than im wondering what sort of training and licensing you had...

You give me nothing; because you have already judged me.....I earn everything.

[jtester]

I am asking my electrician to groove it at least 1 1/4" deep and then fill the groove with sealing foam. I am using RASTRA which has concrete filled tubes inside the foam, but no nailers available.

It is catching on, but still costs a bit more to construct. I am in love with the 12" thick walls, the super insulation, etc.

I've designed electrical in commercial buildings built with RASTRA, but we were required to use EMT because of local codes forbidding NM in any commercial buildings.

Jim T

[cschmid]

were did you purchase this RASTRA and how affordable is it? I am building new house and using this ICF construction as well. I also see many benefits in as well.

[jtester]

I am buying RASTRA from a local distributor. I live in southern NM, and RASTRA is built in Juarez Mexico, about 45 minutes away, and also somewhere in Az. I'm sure there are other plants, but these are in my area.

I can't really judge how much more it costs in my home, I didn't bid framing to compare. The cost for RASTRA blocks for all exterior walls in my 2300 sq ft home including a 14' wall in the great room was $15K. This doesn't include concrete, rebar, installation, etc.

I've heard ICF costs about 10%-15% more around here.

Jim T

[cschmid]

The cost of ICF's here run any where from 17 - 20 dollars a square ft. concrete walls are measure differently then the square footage of a house. It is lenght times height of the wall and the price is also dependent on thickness.

[cadpoint]

Right, thanks on the Typo notice, you made me go read da book :rolleyes:

Interesting articles on its usages and it was described in reference to your OP, if you hold it to class per article. N/A
It wasn't the way I remembered it either, maybe ...
I don't personally like the app / but "OK", somethings going there.

I just can't see working a wall with any of the mentioned tools to install circuits and box out. Hot stick, Dremels, large knifes :) I better get over it

[Cavie]

I wired ICF homes in the earley 90's in Florida. You guys are putting way too much thought into this. I used an electric charcole lighter to cut about 3/4 to 1" grooves down the walls. Used nails to hold it in place just as you would staples down a stud. When you wire rx down a wall, it is in the 3/4 air space between the drywall and the block so why would you need a deeper grove in ICF? In my case, the furring strips were screwed to the walls with tapcons. I just stayed away from them except to get to the boxes. No furring strips to cut or notch, No kick plates to install. No blocks to beat holes in, No foam needed.

[jamesguy10]

I am truthfully sorry for misjudging you. Sometimes i forget that things are different in other parts of the country. Its just that around here there is a lot of NM in older homes, opposed to NM-B, and everyone around here (thats licensed anyways) knows the difference because we use the terms in everyday discussions.

[infinity]

Does anyone have a photo of an ICF installation? Are these typically finished with drywall? If so what it the drywall attached to?

[cschmid]

appology accepted.

infinity I will look some links and send/post a pic of a building in process. this is the only brand that comes to mind this early is logix this is the link to their web sit http://www.logixicf.com/ I hope it works as I have never posted a link on this site before. The plastic pieces i was discribing before the are what the dry wall is fastened to. I believe on logix they are 1/4 thick and 1 1/2 wide but the specs should be on there web page. I will check out some other brands at the local aggregate company.

[blue spark]

I've done maybe 10 ICF homes. All of them I used 1900 shallows, 1/2" mudrings, and sleeved the NM in EMT. I use a hot knife to cut into the foam and stub the NM slightly above ceiling height with a bushing. My new trick was using the higher grade (less expanding) spray foam and glued the boxes and EMT into the ICF. When the AHJ saw it at first he said he didn't like it. I told him to rip the pipe and box out of the ICF. He couldn't do it. Shook my hand and stickered the job.:D

[cadpoint]

I looked closely at the product slide show, only about 50 more question came to mind. :)

I've never worked with the stuff. But how would one attack the main panel, does one have to consider built up finish walls, or preset rods straight of structural framing infoam, or drill back to the Core wall later?
How does the interstructure transpose the load to the out structure?

Is the whole house done with this to the Roof truss? Bold! The whole house is one of those desired emergency structures...

[cschmid]

I have lots of questions as well? Still wondering if anyone has discussed this in the code making process?

[infinity]

I have lots of questions as well? Still wondering if anyone has discussed this in the code making process?


Do you see any specific issue(s) with this type of installation?

[480sparky]

I think he's concerned with three things:

1. Placing the NM next to the concrete itself (334.12(A)(9).
2. Placing the NM too close to the surface 300.4(D).
3. Supporting the cable 334.40.

[infinity]

I think he's concerned with three things:

1. Placing the NM next to the concrete itself (334.12(A)(9).

Shouldn't be a problem if not embedded within the concrete.

2. Placing the NM too close to the surface 300.4(D).

Not an issue if 1.25" away from any framing member. NM cable can be run just behind the back surface of drywall.


3. Supporting the cable 334.40.

May be an issue if the inspector will not accept the cable supported in a shallow groove in the Styrofoam.

[cschmid]

I do have issues with the NM in this installation. no protection from physical damage. Support is where? Staples don't hold in foam and I don't believe a nail stuck in the foam to hold it in place is cool either. If you groove the foam, which I see no other way, and you get it to close to the concrete you expose the NM to moisture which also opens up the spot for mold as well. There really is no framing members just short pieces of plastic to secure what ever you are mounting too. The grooves amount to being some form of wire way, because they carry more than one set of conductors kind of like a gutter I would think but I really have no idea what you would call it. If we look at it from a purely residential stand point it seems pretty much a non issues as long as you and the inspector are in agreeable with the installation. I personally prefer conduit and foam to fill the grooves back up. conduit you can support on the concrete. I am just curious of what others think. I might think it is bigger issue than what it is. Foam emits toxic gas when burned and it burns well. I just have never thought about burning a piece of the form to see how it burns and have not read anything on that aspect either. I don't know if it is a major issue, yet it is a lethal one if it burns in a house fire. Especially for fire fighters and the environment as well. Them are some of my thoughts on it and Yes I still think it is a good building method.

[480sparky]

Foam emits toxic gas when burned and it burns well. I just have never thought about burning a piece of the form to see how it burns and have not read anything on that aspect either. I don't know if it is a major issue, yet it is a lethal one if it burns in a house fire. Especially for fire fighters and the environment as well. Them are some of my thoughts on it and Yes I still think it is a good building method.

This is why some jurisdictions require it to be covered with 'rock whether it's finished or not. I have come across that requirement more than once. HO builds a new home, and doesn't want to finish the basement yet, but must cover the foam with sheetrock. Makes finishing the basement a lot harder later on.

My method is to use a hot knife with a custom blade. I got it at a local boat/marine store. I cut a slot down from the top at each location (recep, switch) and run the NM from the joists down to the box (usually a 1900 with mud ring). The depth is just shy of the concrete, so there's a little bit of foam still there. I then take the strips of foam I cut out and slice a bit off the back, then use a little non-expanding spray-can foam to secure it back into place.

[normbac]

I am doing a bid on a 5000sq ft home that has icf walls cut into hill for bottom floor, main floor with garage are stick frame. Do you guys that have done these see a significant time and material difference. Do you bid these different than a normal wood frame, percentage wise?? Any info would be appreciated. TIA