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#168293 08/31/07 08:47 AM
Joined: Mar 2006
Posts: 52
So -
I'm walking out the door after completing the rough wiring in my brothers mega buck custom built home when the foreman stops me and sais hey, just wanted to let you know. A few months back we had a problem with one of the houses we built. The phone system would not work after rough. After investigating they found that the spray insulation that they were using actually melted together some sections of the Cat5. (Chemical heat reaction of the curing process) 2 hours later after me refusing to have HIM touch/move my low voltage runs, he assured me that he would be "on top of" the whole insulating process, even wearing the proper breathing gear etc. to keep an eye on these guys as they spray. I went home in a semi panic and researched the web. BASF is the company that makes the foam. After talking for some time with them, I found that there are two different types of foam that they use. One is called a "open cell" foam, meaning it has bubbles in it. It only reaches 200 degrees Farenheit when curing and doesn't affect most wiring. Unfortunatly my brother ordered the closed cell version that has very high insulating properties and NO bubbles inside. The rep. said this foam hits 300 Farenheit when applied 2" thick and that I would definetly want to protect any low voltage wiring from it, but my romex should be OK... I've got that sick sinking feeling now. Not only for my low volt runs but, all that romex as well. My brother cant seem to grasp issues like this and doesn't seem to concerned because "they are professional home bulders" I did a beautiful job wiring this house. The Inspector, who is a man of very few words simply said "Great job!" - - - I'm beside myself now wondering what to do/how to cover my butt. They are spraying this stuff right now. Anyone have some input as to what I can do at this point? They told me before the job that they were going to foam insulate the house, not cook all of my wiring.. I'm sick Thanks

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Joined: Dec 2002
Posts: 339
I am sorry to hear this, but I hope to profit by learning from this. I greatly appreciate your making me aware of this possible problem. In my limited world, I had not heard of this. I would be sick also.

I hope that no problems develop, and would like to know the end result with pictures especially if it does go bad, whether the info comes from you or someone else. Also shy of using conduit what has been done by others to protect the wiring.


Joined: Oct 2006
Posts: 745
That's not good news. I hate to think of all of the dozens of phantom problems that we have chased with low-voltage wiring, especially in newer homes. Thanks for the heads-up.

I smell a class-action lawsuit in the makings.


"But the guy at Home Depot said it would work."
Joined: May 2007
Posts: 169
I'm very sorry about your situation.
Maybe a few new lines in the standard contract are in order for the future.
I don't know if this is a common construction product in your area but I haven't seen it in this neck of the woods. Our insulators do use canned expanding foam in our top plate holes though. Maybe I ought to measure the curing temp on some of that stuff.
I know for a fact that if I were in your shoes I would right now have a scrap of romex, a scrap of cat5, and a scrap of RG6 in the oven baking at 300F so I could have a look at what that temp sustained is going to do my wire. How long does the curing process sustain this high temp? The wife will kill me but I'd need to see it with my own two eyes.
Did you do any audio runs? A scrap of that two. Of course I'd have the extinguisher handy.

If this is an established construction practice please forgive me for my ignorance. Unfortunately it's what I have the most of.
But it seems to me that that if indeed the insulators are applying a newly developed process that could possibly damage a number of long established traditional construction processes (romex, cat3 or 5, RG6, PVC, ABS, etc) that it should be up to them to inform the builders with enough notice for him/her to inform everyone involved to prepare for it, and especially include that preparation in their proposal.
Class action? If the manufacturers clearly stated the curing temp on their products cut sheet and packaging I'd think the burden would be on the installers, and ultimately, on the GC. Somehow "Were going to foam the house." doesn't seem to convey the dangers that "Were going to foam the house with a product that cures at temps reaching X degrees for a period of up to X minutes." conveys.
Sorry again.

Last edited by ChicoC10; 08/31/07 04:44 PM.
Joined: Feb 2003
Posts: 368
At least you know about the potential problem now and not after its closed in and you are wondering what went wrong.

I have only seen foam used on the TV shows (Holmes on homes, TOH, etc.) and did not know that it got that hot after application.

Is it possible to ring out the wire runs to see if they are bad before the drywall goes on? I was thinking if you had a bad run you could use something like a roto-zip to grove out a small channel to place a new low voltage line through the cured foam.

Joined: Mar 2006
Posts: 52
I really appreciate the replies - I've been stewing about this most the day. No pun intended. When things like this happen to me I try to find the reason why - Like, was it my fault... I couldn't believe a large builder like this would throw me this at the last second. Didn't make sense. Until, I remembered just earlier today, the stapled bunch of papers that the foreman quickly tossed to me during lunch in the last week of rough. He told me then, just some more info to cruise when you got time. Sure, I've been on this job by myself for 5 weeks and in the final week they throw me what the foreman loosely regarded as "more info" was actually the "project manual" - When I first received it I quickly spied contractual agreements and related issues (things worked out long ago with the brother) and I tossed it into the truck. Finally, 2 hours ago, I read the 31 pages complete. There are 16 divisions showing details for the individual contractors. There it was. On the last page, last paragraph that says:
Line item 1650: Telephone system, Intercom, audio, T.V/Video Note: All rough-ins from above that are in insulated spaces shall have air tight surrounds. That sinking feeling got worse... I actually drove to the site to check things out just earlier after dinner. They actually did NOT get to my main low voltage trunk lines yet... (WHEW!) I'm going back tomorrow on my own time to pull all of those trunks lines clear out of those spaces until they are done. One big lesson learned for this boy... I am planning a test just to see whats happening to my romex. I will place romex, Cat5, Coax and whatever scraps of communication wire that I can find into a "wall cavity sized box" and have the insulator fill it up to the same degree that they are filling those 2X6 walls with. I will report back, with pictures. Thanks everyone.

Joined: Jul 2002
Posts: 717
Good luck to you on this. The problem about the romex is that you might not find out the real damage the heat / surrounding hardened foam is doing to your cables until they get energized with enough current to create extra heat that might just throw them over the top...

Joined: Mar 2006
Posts: 52
Originally Posted by macmikeman
Good luck to you on this. The problem about the romex is that you might not find out the real damage the heat / surrounding hardened foam is doing to your cables until they get energized with enough current to create extra heat that might just throw them over the top...

- At least the romex worries I can leave to the builder as they have no requirements/make no references to sleeving the 120/240 stuff. The good thing is, my brother asked me to do this job because the incredibly bad "flicker factor" that he was experiancing with his previously built custom home. (Same builder) They stretched/overloaded many of the general lighting/outlet circuits. I made sure that wouldn't happen by adding plenty of home runs and paying close attention to loads, voltage drop etc. I've also have my two sub panels located in the middle of the basement, not in the outside insulated walls. It's just too bad, what money can't buy. Now, if I was the other guy who just completed wiring this builders other house, with it's overtaxed circuits/panels sitting in outside insulated walls - I might be a bit more worried.

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