Working in Cellulose Insulation...

[Felder]

Howdy all. Does anyone have a tip for working in an attic covered with cellulose insulation? We have knob and tube wiring in the attic covered with mounds of insulation at least 18 inches thick. I need a way to get the cellulose insulation out of the way so I can trace the wiring and inspect/replace it. I can't just shovel the stuff out of the way because of the wiring. I'm tempted to take my leaf blower up there this weekend and see how that works. Anyway, I'm open for suggestions.

Thanks, Felder

[Speedy Jim]

Argh! Leaf blower will make a huge mess and dust throughout the house, I bet. In addition, you will need substantial respirator protection. Consider a fan pump fresh air into the work area as well.

How about experimenting on a smaller scale with a vacuum cleaner connected to blow? If not a shovel, maybe a hoe?

Technically, cellulose shouldn't cover K&T. However, one large city (Philly, I think) did a study involving a large number of city houses retrofitted with cellulose and found no problems.

Link here:

Jim

[sym]

ahhhhhhh welcome to my nightmare. well a dust pan fits between most bays nicely and maybe a bunch of trash bags, bag some and remove then pile some of it in areas already inspected or void of wiring. hmmm gonna be some cussin goin on.

[M Q]

Can you just scoop it with gloved hands? How about a large shop vac?

BTW, insulation over K&T wiring maybe kind of iffy. I am not sure, but you may want to check into that. It seems that NEC prohibits insulation over "concealed knob and tube" (392.12 NEC 2005), but seems to be silent on "open wiring on insulators" (Article 398 NEC 2005). Various jurisdictions seem to sometimes have different rules than NEC.

[Pat]

A contractor quoted me $2000. I bought a Harbor Freight dust collector for $180. I stuck the blower in the center of my attic and ran 30 feet of 4 inch pipe out the end of my attic. I hooked up two sets of vacuum hoses to the blower and my wife and I vacuumed the attic clean in two days. We shoveled the pile of insulation into lawn bags and took it to the dump.

[Steve Barker]

Why'd you throw it away? you could have blown it back in when you were done.

steve

[Pat]

I considered it. Decided to have new fiberglass installed after the work is done. As it turned out it would have been rained on anyway. I put the blower back in the box and sold it for almost as much as I paid for it. Made the job very inexpensive.

[Pat]

Tried to give it away. No one wanted it.

[Bob F]

Broom.

[hallerb]

YOU SHOULD NEVER COVER KNOB AND TUBE WITH ANY INSULATION EVER!!

Its past time to rewire your home, and if you have a house fire its very possible insurance wouldnt cover your loss

[Pete C.]

Second that, *HUGE* fire risk there. K&T wiring was and still is quite safe - when it is left as it was when it was installed - all the risk of K&T comes from people modifying it, over fusing it, burying it in insulation and other changes.

At this point the only practical thing to do is to vacuum it out with the biggest shop vac you can get (rent a true industrial one) and empty the vac'd insulation into some really big moving boxes for temporary storage. After removing all the insulation, remove all the K&T wiring and replace it to current code. After the wiring issues are resolved, rent an insulation blower and plow the insulation back into the attic.

Remember your PPE - Goggles and respirator, as well as gloves, knee pads and a hard hat (roofing nails to the head hurt).

[hallerb]

and check all the walls too. some insurance companies dont cover K&T wiring and it can be very hard to sell a home with K&T because the buyer cant get homeowners insurance

[dpb]

[e-mail] wrote: ...

Well, one can assume OP has insurance already and if it were a concern at the time they wrote the policy, they would have asked. Again, FUD. :(

If somebody buried it under full depth insulation, that could be a potential problem, granted, and it shouldn't be buried, but not covering an underwritten policy is _highly_ unlikely.

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[dpb]

Don't suppose responding here in January will help OP much for a coming weekend last August... :)

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[bud--]

. It has been a code violation to insulation after about 1987 (394.12-5).

Never cover? Huge fire risk?

(originally posted by Phil Munro) is a report to the Illinois Department of Commerce and Community Affairs on adding building insulation around existing K&T wiring. No record of hazard was found in the large number of K&T installations that had insulation added around them. Also addresses how some jurisdictions have handled the code aspects.

If the post was timely, I would suggest moving cellulose with a large piece of cardboard. (good eye Duane)

[Pete C.]

Yes, huge risk. Given the substantial probability that a K&T installation with marginally 14 ga wire now has 30A fuses on it due to blowing the 15A fuses from all the modern devices plugged into the small number of circuits typical in a house with K&T, it's a big risk if it's uninsulated and a huge risk when buried in insulation. If the K&T is still properly fused it's probably fine, but that's a pretty big if considering the K&T installations I've seen.

[sylvan butler]

Insulation alone around the K&T wiring isn't usually a problem. What it does is reduce the margin for error. E.g. what if you now have a roof leak?

sdb

[hallerb]

K&T was designed for free air flow around conductors at all times. insulation prevents that and can cause overheating and ultimately a fire since connections are soldered in walls, get solder hot enough and it will fail

[sylvan butler]

Yup.

Well, K&T was designed not to get significantly hot during operation. However if the fuses have been replaced with bigger units it might get hot, and then as before, the insulation didn't cause the problem, but it did lessen the margin for error.

Not proper K&T solder connections. The solder is just on there to seal the connection (so it won't corrode) and is not necessary for mechanical strength (because it has none) or electrical conductivity (because lead and tin are not that great of conductor). If you have ever tried to take apart such a joint, you would know what I mean.

A well done joint will not even drip molten solder unless mechanically disturbed while the solder is liquid, but no worry even if it does. For a summary of K&T splicing, see this pdf:

I didn't create it, but whoever wrote it did a good job.

sdb

[S. Barker]

The problem with this theory is that it's never been proven. There's never been a fire that was proven to be because of K&T wiring that was covered by insulation. It sounds good on paper and gave the NEC boys something else to screw people over about, but in all reality, it just doesn't happen.

s

K&T was designed for free air flow around conductors at all times. insulation prevents that and can cause overheating and ultimately a fire since connections are soldered in walls, get solder hot enough and it will fail