I have several clients who could really use a blanket of cellulose insulation added to their attics. I like cellulose for all the usual reasons, especially because it’s opaque to infrared energy, while fiberglass is transparent. Anyway, no insulation contractors in the area (Raleigh/Durham, NC) will blow cellulose. (In fact, most will only do new construction.)
So I figured, why not rent a good, commercial blower and do it myself? Turns out none of the rental companies have one. By ‘commercial’, I mean a machine with a big hopper that can take several bales of insulation at a time, and that has a remote control at the spray end, allowing one-man operation. The little “hair dryers” they rent at the home centers are not acceptable, because they’re too weak and require constant attention.
So this is really two questions: 1) Why do you suppose nobody is installing cellulose? and 2) Do you know of a commercial insulation blower manufacturer where I could at least start chasing down a machine? Web searches yield no useful information.
Thanks! Any information appreciated.
-Jonathan Ward
Replies
we use an old ( 1980 vintage ) US Fiber.. with a Hurricane blower.
can take a bale.. but you really have to have someone tending the feed anyways
try a google search on US Fiber blowing machines... should be one used on Ebay or something..
lot's of insulation companies go belly up, so the machines are out there..
Regal Industries sells machines...
National Fiber sells machines...
but i gotta believe there's a bunch of old hippies still hanging around in your area who can, and do, blow cellulose... you just haven't found them yet
What do you know about BIB's (blow in blanket - FG).I was under the inpression that it had chopped fibers and an adhesive that held it together as it was blow on a wall. Sorta like damp spray cels.But I saw a Bob Vila show where they where using it and they covered the wall with a mesh and dense packed it in like you do with cels.
bill... i 've never seen bibs... but in the end , it's still fiberglassMike Smith Rhode Island : Design / Build / Repair / Restore
I've been using BIBBsIt is about 2% less effective than cellulose, 3% more expensive, and twice as clean.It is far more fireproof, and mold resistant than cells. properly instralled, it is like cellulose in resisting convection, contrary to what Mike says, it is not like FG batts in any way, from a performance viewpoint.IMO, the pros outweigh the cons in relation to cells, but I still go foam when there is top dollar budget involved.
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Do you do dense pack or is it adhesive and blown against the wall?They did not do a close of on Bob Vila, but looking at the stuff and they played with it in there hand it seemed to be realitvely small sections that would pack and not the fluffy stuff that is in the bats.Do you use the same material for attics?
denspack, tho in cielings, it is less possible to pak it. When he can do dens pack in a cieling, he can fill 11" tight and give same rating approx as 15" loose fill and with less convection.By now you have read my other comments on texture, cleanliness, etc.Everybody else, - by time i have read this thru, I need to clarify - because it seems some have been confusing Blown in Blanket System fibreglas with regular FG batts, which are IMO, a nearly complete waste of money, and with sprayed in foam.
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paul... if you pass a flame over the bibbs, what happens to it ?
does it melt ?.... at the same temperature as regular fiberglass ?
that's what happens with fiberglass, it melts..
cellulose , mfr'd to ASTM & FM standards, does not burn ... and it does not melt..
it continues to protect the structure ...
Mike Smith Rhode Island : Design / Build / Repair / Restore
To be honest, Mike, I have never passed an open flame over the loose FG.Either FG BIBBs or cells will inhibit fire spread due to control of the air movment on the flame. Stopping the draft will prevent flame spread. There may be something to what you say - that if the FG fluff will melt down more quickly in hot flame, it would loose that advantage more quickly, but to my mind, if there is a hot flame having itself a party, the house is already in trouble.Same thing applies to the cells though. It will burn. You want me to recount all three stories again? We did this last year . Maybe in the idea test scenario, there is no flame spread in cells, but not every case is ideal, not every installation is ideal, and not every manufactured product is perfect. The fact that it is chopped newspaper that HAS to be treated to resist fire is placing all your faith in a manufacturer.Hmmm, ever seen a manufacturer mess up?
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The makers of "that pink stuff" have the marketing aspect of insulation cornered.
Cellulose is making headway. Years ago we used to get slammed on this forum for recomending cells over FG...I've seen the attitude towards cellulose change 180 degrees in the last four or five years.
To add on to Mike's suggestions, look into Krendl blowers as well. Very nice machines.
I don't have any recommendations for your area.
Edit: gramer and spalling
Edited 1/19/2005 3:22 pm ET by Mongo
Timely thread..I just talked to a guy who would blow either glass or cellulose, but he was trying to tell me that the glass was better. The air infiltration was better with glass,glass better fire proof,water not affecting etc etc...Same price....Hmmmm..
"The air infiltration was better with glass,glass better fire proof,water not affecting"
False, false, and false. Just say no to FG.
seb...
<<<The air infiltration was better with glass,glass better fire proof,water not affecting etc etc...Same price....Hmmmm..>>>
he's either uninformed or blowing smoke
air infiltration is much worse with FG
glass will not burn, but it will melt... FAST ... once it's melted, all the stud bays become chimneys.. the fire gets into roof much faster.. i've built demonstration buildings for "The Big Burn"... cellulose will not burn nor will it melt.. when everything else is ashes.. cellulose will still be there
fiberglass becomes a thousand condensing filaments in the dew point zone.. the moisture vapor will condense, coalesce... and drip down onto the horizontal members..
cellulose will absorb and release moisture until it reaches the saturation point.. if it reaches the saturation point .. the building has bigger problems than insulation
if it's the same price... ?????? why use FG ?Mike Smith Rhode Island : Design / Build / Repair / Restore
Our blower is about 25 years old too. You can rent them from Lowes around here but they are a consumer version that will work on a 15 amp breaker so they take for ever to fill the house. Rented it once and took 9 hours to blow the sidewalls of a house. Did the one across the street 2 months later after purchasing ours and did it alone in 5 hours. Huge difference with a good one.
I also called around and found a cellulose plant just 15 miles from my house. Saved 2.25 a bag if I buy 100. Works out to a third vs. Lowes price. Doesn't look like a huge operation so you might look around your area to see if one is available. DanT
<if it's the same price... ?????? why use FG ?
Mike, I agree that it is the best. I originally asked him about cellulose, and he started the smoke screen that went against all I thought I knew.
We have very low moisture here and there is already 5 inches of cellulose that has been there for 50 years. I posted the question because I needed the confirmation from someone better versed than I am in the subject. Thanks for the confirmation.
Are you sure you have low moisture? I've been there several times times and only once did I feel the moisture level was lower than 10% humidity was often over 50%
frenchy... i live in coastal Rhode Island... our summers are as humid as it gets... most houses have problems of mildew in their closets in the summer
cellulose does not have a problem with high humidityMike Smith Rhode Island : Design / Build / Repair / Restore
The dew point here has been less than 20F for months..The real measure of humidity however,is the summer dew points...It is unusal to get into the high 50's in the summer. When it does all hell breaks loose with thunder storms...The eastern dew points are routinely in the 70's in the summer...
I've seen cellulose burnseveral times
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A few years ago I did a cellulose dense-pack in my home because of the info I got from this site - love it. One of the selling points for me was the fire issue. <!----><!---->
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Out of curiosity… in one hand a wad of the cellulose, and in the other my lit MAPP torch. It just sorta glowed – like the fake embers of a fake gas log fireplace, and couldn’t feel a thing.<!---->
<!----> <!---->
Any one dumb enough to try it with the Pink Stuff? I'm not.
Never underestimate your ability to overestimate your ability
FG BIBBs is not pink, it is white, more like cotton tuffts to touch
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I'm guessing here so please don't jump all over me.. it may have to do with humidity. Cellulose doesn't like to get damp, it loses dramatically it's insulation value as it's moisture goes up.. in addition it can cause some serious issues if it gets wet and stays wet for extended periods of time..
Over on the fine woodworking site they constantly speak about how damp that area is and how it's nearly impossible to dry wood much below the high teens in percentage of moisture..
I dislike fiberglas fro a variety of reasons and it's poor properties with regard to getting wet are right up there.. Instead I prefer foam.. water/moisture doesn't affect it, it's R value stays the same without regard to ambiant tempurature structurally stiffans a house by a dramatic amount, provides a great air infiltration barrier naturally (neither fiberglas nor cellulose does as well).
The down side is a higher cost and the requirement of serious equipment to inject/ spray it..
frenchy.... nothing likes to get damp.. cellulose ,foam or fiberglass
if you are not controlling the humidity within the space there is going to be a problem.
with cellulose.. it will dry.. with fiberglass, it will drip
john sprung... so ?... is that a problem of cellulose... or an uncontrolled leak ?
if the insulation were fiberglass, and it was wet.. would the improperly wired lamp still have started a fire ?
and .. when the fire started.. what burned ?... not the cellulose
why do we have all of these extraneous things clouding the issue? in a building.. you have to control the moisture.. you have to prevent leaks... you have to properly wire it.. none of those things have anything to do with choosing your insulation
Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike, I don't think damp affects foam to the degree it affects other insulation.. Take a chunk of foam stick it in a bottle and fill the rest of the bottle with water. Shake like crazy and leave set for a good long time..
now measure it's R value.. Bet it's the same! try that with any other type of insulation..
The negatives about foam are well known, cost, dense black smoke when exposed to direct fire Although most won't burn.. and needs to be covered with sheetrock to meet fire code..
Let's clarify what we mean by "foam".... For retrofitting, we're talking open-cell foam, how does that compare with cells for dealing with humidity? For my bathroom remodel I was able to tear out walls and put in styrofoam, for the rest of the house I have to live with whatever the benighted POs did for VB (almost certainly nothing). It seems to me (relatively uneducated as I am though) that even open cell foam is going to be better than cells, better air sealing and better able to handle high humidity (less permeable than cells....?). I seriously doubt that one can dense-pack cells in walls in a retrofit, the caveat I've heard about cells in walls is that it settles over time and you lose R-value. Then there is the whole issue of PBDEs.... Cons against foam: (a) cost and (b) flammable and gives off groovy fumes when it burns.
Has anyone on this topic ever seen or used this product? It is a type of foam.
http://www.airkrete.com/index.html
Foamed cement, R-3.9, Will absoutly not burn or contribute smoke to a fire.
I've only read about it and all I've read sounds good. But; never seen a price for it.
I'm sold on cellulose, but I talked to a PA home inspector recently who told me that cellulose will be "outlawed" in the next couple years due to the scare over mold and mildew in homes. He felt home sales contracts will be changed to include this inspection just as lead, asbestos, formaldehyde foam, and radon in the past.Anyone else here this?
No. And if there's mold on cellulose, as with anywhere else in a house, it's because the moisture content is too high because of some different problem.
It's hard to say enough good things about cellulose.
Andy
Andy Engel
Senior editor, Fine Woodworking magazine
Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig
Edited 1/21/2005 12:43 pm ET by ANDYENGEL
dear ALL: just so i don't single anyone out....
what a crock of ....
cells do not promote mold & mildew...
and yes, you can dens-pak cells in a retrofit...
and just how were you going to retrofit whatever it is you were going to use..
c'mon.. i didn't just fall off the turnip truck.. i have a genuine concern for my customers and my liability..
i've used a lot of different insulation...
i've never used foam-in-place.. but i've investigated several times.. it was always cost-prohibitive..
i've never used Bibbs.. but the jury is still out on bibbs..
as for mold, knob & tube wiring, wet insulation, mildew, water absorption.. gimme a break.. each one is a different situation and each requires a different solution..
wet houses are wet houses... bad wiring is bad wiring.... is it ok to use bad insulation around knob & tube because it's so ineffective that the wire will not heat up ?
another false rumor.. cellulose will be banned because of mold... c r a p Mike Smith Rhode Island : Design / Build / Repair / Restore
Neither do I buy that line about cells being outlawed due to mold. Cells won't support mold, but they do hold onto moisture which can <encourage> mold growth in the surronding lumber. The biggest problem there is whatever situation that lets the cells get wet in the first place.I'm not attacking you or cellulose, just defending my choice of BIBBS as being better for me on my jobs. Both have pros and cons. I've used both, and seen some problems from cells, and moved on.Dollar for dollar for R-value, denspack cells is probably the best insulation choice you can make. Anotherr thing that came across my mind today about this - All the problems I have seen in cellulose - the rot, the fires, were all on installations in the seventies. has the manufacturing and installlation quality improved since then? If so, that improves the case for them...
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mike,
no insulation is good around K&T but any type of insulation that can be blown into a blind space is especially bad for K&T.
I cant tell you how many houses with old wiring that i have opened the walls to find the cells packed full.....
I think it is more that installers need to be educated more on what is ok and what is not
in a house with modern wiring give me dense pack any day...
in my old victorian with K&T , wait until i take care of the wiring in that area of the house then pack them good.
problem comes when Home owner calls insulation contractor to fill up his walls not knowing or careing what kind of wiring he has in his walls and the insulation contractor just sees a job and $$ so he pumps them full without asking.... alot like the dont ask dont tell in the millitary.
james
james... absolutely... with K&T wiring we don't blow those walls at all..
we wait until they want to upgrade the wiring......a couple of drafty winters moves those projects up on the priority listMike Smith Rhode Island : Design / Build / Repair / Restore
I stumbled across this recently...pertains to some of the discussions. Some numbers on fire resistance for cellulose, FG, etc. I have no clue about whether it's on the level.
http://www.toolbase.org/tertiaryT.asp?DocumentID=3966&CategoryID=1402
Some excerpts:
"Scientists at the National Research Council of Canada report that "cellulose in the wall cavity provided an increase in fire resistance performance of 22% to 55%," relative to fiberglass batts, provided the cellulose is treated with fire retardants. A similar effect may occur when using blown-in fiberglass without a binder."
also...
"The cost of fiber insulation is dependent upon the method used to close the cavity; typically about double the cost of fiberglass batts. Cementitious foam ranges from $.30 to $.50 per square foot."
I've learned alot just "listening" (lurking) behind the scenes. Keep up the great discussions.
Thanks
Taylor,
the spray in stuff is generally called open cell while the sheets (pink blue etc.) that you buy are generally closed cell.. open cell stuff generally has an R rating of 4 per inch while closed cell stuff has an R rating of 5 per inch..
Dealing with fire, there is a requirement to cover all foam with sheetrock and if they did a good job of filling the wall cavity there is no or almost no space to provide the required oxygen needed for fire thus little or no chance of dense black clouds of smoke.. I used SIP's (structural insulated panels) which are plywood (OSB) glued to a block of foam glued to a sheet of plywood (OSB) thus there is absolutely no way for fire to get started and burn.. One of the things I saw was a video of a bonfire burning in the corner of a house built with SIPs. the tempurature on the sheetrock was over 1300 degrees, more than enough to cause wood to burst into flame. yet the wall panel on the outside was only 50 degrees warmer than ambiant tempurature.. that fire burned for over an hour and yet there was no smoke emmitted..
I'll join those who claim that properly treated celluliose is extremely slow to burn and tends not to support combustion.. so there is little to offer there between the two.. regarding fire... fiberglas on the other hand....
As for settling, SIP's have been used since the 50's chances are your convience store uses them. also most resturants and grocery stores. They call them freezer panels when instead of OSB they use stainless steel but they are the same thing.. if there was an issue of settling with the foam I doubt they would be so universally accepted.. As for sprayed in foam settling over time, there was some instance of the early stuff used in the 60's settling but they found it had been improperly sprayed. Since that method of spraying foam is no longer legal and it was extremely expensive as well, I think that can safely be put into the uban legends pile of nonsense.
However it is a fact that both fiberglas and celluliose will over time settle..
As for dealing with humidity. Take a coffe cup. (it's made with the open cell stuff) Pour steaming hot coffee into it.. now how much moisture do you feel on the outside? Think your area ever gets that humid? OK, I'm a bit of a smart aleck and I do appologize. I've looked carefully at every type of insulation there is and in the end for our extremes of cold and for long term insulation with the fewest potential problems foam is the answer..
I really hated to find that out because foam is the one insulation that really needs a professional to install. there is a serious investment in equipment plus the requirement of some formal training and I hated to give that control over to others. I am a proud do-it-yourselfer and that loss of control plus paying others to do something really gauls me..
However it is a fact that both fiberglas and celluliose will over time settle..
Well, maybe. I don't know about FG, but I know that when dense packed in a cavity, cellulose is compacted to a greater density than natural settling could take it. Consequently, dense-packed cellulose won't settle.
Blown loose into an attic, cellulose will settle. That doesn't matter, however. By law, the r-value for a given depth of cellulose as printed on the bag's label is that for the eventual settled depth, not for the as-blown depth.
AndyAndy Engel
Senior editor, Fine Woodworking magazine
Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig
Andy,
In the for what it's worth file, As I take this old house down I notice even though the fiberglas was installed about 25 years ago and a carefull job was done, there is any place from a half inch to two inches at the top of each stud cavity where there is no insulation.. the roof insulation blown in over top of the rafters and yet was packed down to less than three inches.. I suspect the reason it was so packed down is because here in Minnesota we get damp periods during the winter, The celluliose get damp due to fog, moisture etc. coming in the roof vents, freezes during the next cold snap and a little compression happens. Multiply that times all the damp days in the winter and suddenly the celluliose winds up much more compressed than it should. I'm at the end of a dead end street and I don't doubt that if I had heavy traffic or sysmic activety things would be worse..
frenchy... bs...
<<<Multiply that times all the damp days in the winter and suddenly the celluliose winds up much more compressed than it should>>>
have you ever heard of wet spray cellulose ?
or "dens-pak "?.. you cannot compress cellulose more than it should
and the humidity that is absorbed...is released when the conditions changeMike Smith Rhode Island : Design / Build / Repair / Restore
Mike
When I bought this house I peeked into the attic, the celluliose was well over the rafters, as I tear it down it's about 3 inches thick.. very dense but about 3 inches thick.. there was an excellant and complete 6 mil poly vapor barrier with taped edges.
I've kept my eye out for some sort of hole/ acces for interior water vapor but to date I've found none!
you damn liberal... what's your point ?
the cellulose was compressed ?..... so ?
and it got wet ?..... and ?
hey.. you want to use sips... that's great, but what's your knock on cellulose ?
i go in a lot of attics.. the ones that have a lot of activity have compressed insulation.. wether it's fiberglass or cellulose
also... one trick of unscrupulous or incompetent insulators is to "fluff" the attic blow..
using more air than needed to place the product ....
if you want to know how much insulation you have in your attic, you have to get a bale count.. this will give you a lb/ sf figure...... since the settled density is apx. 2 lb/cf.. you can get your installed R-value from that..
you can't get a true R-value by measuring with a ruler if you don't know what the density is
perhaps your attic was fluffed.. and all of your construction activity compacted it to its settled density...
if you actually place things on top of it and squash it, you will acheive a Dens-Pak density ( about 3 lb/cf )..... dens-pak has a slightly better r-value that normal settled density Mike Smith Rhode Island : Design / Build / Repair / Restore
All right, fess up...
How many of you'z guyz work for Owens-Corning?
Mike,
there was never anything up in my attic but it did get damp every year and that's what I believe caused my compression.. I see your point I think about a dense pack having slightly higher R value but if it was 9 inches before (and it'd been insulated for several years before I moved in) and after 25 years or so it was now 3 inches and the R value of cellulose is say 4 per inch I then had a R value of 12,... in an attic.. ... in Minnesota..
I will say that my heating bills the first few years were reasonable but recently get over $400 per month in the dead of winter..
I don't see foam being affected by dampness and that's why it's my insulation of choice..
as for a higher R value when compressed, that interests me. I always thought that a certain amount of air was required in order to obtain the maximum R value. that if everything was compressed it would tend to react more like a solid than a true insulation.
frenchy.. a certain amount of trapped air is neccessary..
but what is a solid ?
wood has various weights of from about 20 lbs./ cf to 60 lbs./ cf
cellulose in a bale weighs 26.5 lbs.... installed in a Dens-Pak.. it's around 3 lbs./cf
settled density is about 2 lbs./cf
i would IMAGINE that you might be able to install it at about 4 lbs./cf given the right circumstances
Mike Smith Rhode Island : Design / Build / Repair / Restore
I'm not surprised that the FG settled. That the cellulose in the attic settled isn't surprising either, but as I mentioned before, that settlement simply doesn't matter.
AndyAndy Engel
Senior editor, Fine Woodworking magazine
Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig
"the spray in stuff is generally called open cell while the sheets (pink blue etc.) that you buy are generally closed cell.. open cell stuff generally has an R rating of 4 per inch while closed cell stuff has an R rating of 5 per inch.."Sorry, Frenchy, but this contains several errors that need correction here.Sprayed foam insulation can be at least three diff kinds.
icynene is open celled and about R4
urethynes are closed cells and R7foam panel sheets can be open celled isoanurate at r7 or closed cell polystyrene at R 5
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Sorry Piffin, I was trying to simplify it. With this crew here I should have known better, however if every statement needs a lot of cavots and clauses, this site won't be as accessable as intended..
Around here I have yet to see urethanes sprayed in so a assumed it would be rare in most locations too.. (and I visit about 2500 new home sites a year for my job and have done so for 14 years) I did read that urethanes are far more expensive to spray so that may be the prime reason, but since since most homes in my neighborhood are really high end places you'd think if I were to see it anyplace it's be around here..
Most of the pink/blue stuff you see is R 5 polystyrene
> john sprung... so ?... is that a problem of cellulose... or an uncontrolled leak ?
This was in Florida, the water was from a hurricane. They fixed the roof afterward, but the cellulose was left wet.
> if the insulation were fiberglass, and it was wet.. would the improperly wired lamp still have started a fire ?
Can't say for sure, but the acid they found came from the cellulose. That acid greatly increased the conductivity of the wet cellulose. FG would not have affected the pH. OTOH, if they had put the aluminum side of the FG in contact with the wires, maybe they coulda had a fire without any help from the hurricane.
> and .. when the fire started.. what burned ?... not the cellulose
Yes, unfortunately, the cellulose burned. Apparantly the water washed out whatever it was that was supposed to make it fire resistant. There's also the formation of the carbon trails. I don't know whether that had any role in the failure of the fireproofing. The carbon is conductive, though.
Anyhow, the fire expert from Texas built a demonstration setup, plugged it in, and got it to burn.
All this is from memory of a show I saw on Discovery or TLC within the last couple weeks.
-- J.S.
john .. the fire experts have been trying for twenty years to scare people away from cellulose...
it wouldn't surprise me if the fiberglass mfr's association paid for that little experiment and the video you saw
do you remember the "60 Minutes" expose of the dangers of cellulose in about 1980.. what a crock that was
the truth is that cellulose is much safer than fibergalss for fire safety...
and why ANYONE would leave ANY wet material in a structure is just incomprehensible...
if you soaked an attic full of fiberglass insulation in that hurricane, what would you do?... take it out , right ?
if you soak an attic full of cellulose insulation , what would you do ?.. take it out right ?
they both end up in the dumpster... these are straw man arguements
but hey, whadda i no ?
Mike Smith Rhode Island : Design / Build / Repair / Restore
> it wouldn't surprise me if the fiberglass mfr's association paid for that little experiment and the video you saw
Actually it was paid for by the defendant in an arson case. Come to think of it, the show may have been "Extreme Evidence" on Court TV.
> and why ANYONE would leave ANY wet material in a structure is just incomprehensible...
In this case, it was a rundown rental. The tenant was the defendant.
Yes, if it were mine, I'd have dumpstered the wet insulation and sheetrock.
-- J.S.
You are right that if the moisture gets to it, any insulation will suffer, but the FG will dry faster, tho the biggest problem is that the moisture gets to it in the first place.
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once wetted, the cellulose takes forever to dry, so it encourages rot in framing members. There may be something to that speculation yours
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The downside to blown insulation is that it's a royal pain to work around. It's messy. You have to make and patch holes in every stud bay. It gets dangerous when combined with K&T or bad wiring. I saw a case on TV where a fire was thought to be arson. The defendant found an expert who proved that wet cellulose over a mis-wired ceiling light caused an acid to form, which led to arcing and carbon trails, and finally a fire.
-- J.S.
Just where does one turn????
It really sounds like there is not one type of insulation that is better than the other. Sounds as if all are faulty????
We're doing an addition/remodel very soon and its like just when we decide what we're using for (in this example) insulation. We end up getting more conflicting stuff.
Confused? I'd say. I might be better off just blowing corn husks in my attic. I can get junkloads of those at no costs.
What is one to do????-----------------------------------------------------------------------------
"It is so, because Piffin tells me it is."
All design and materials selection is a series of compromises. Get used to it- it's life. Listen to the various opinions, weigh them and make your choice. None of them are perfect. What is optimal for your design, your heating climate and your pocketbook is different and everybody here has their own point of view. Different problems are given different weight by different people. And all insulation systems will do the job if the installation is properly designed and meticulously installed with all the right components.
Just hope that once you come to the conclusion about what the right thing to do is, that the @&@#$ building plan inspectors will give you a permit to do it that way!
Just break out the wool blankets;)
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I guess (from your tag) "just ask Piffin". He'll suggest blown in foam.
Did you know that crumbled dry corn cobs were sometimes used as insulation a long time ago? People must have experimented quite a bit in the old days. I've seen crumpled newspaper, ground cobs, and dry stack bricks inside walls cavities of old homes in Iowa. It was the bricks that really surprised me. They were obviously used and were stacked in whatever way in the cavities of the outside walls. The other two were lucky they didn't burn!I'm thankful for the loyal opposition! It's hard to learn much from those who simply agree with you.
Yeah I sort of remember my uncle talling me about the corn cobs. Couldn't remember if it was the corns cobs or the husks ( I think they just smoked those)-----------------------------------------------------------------------------
"It is so, because Piffin tells me it is."
It was the corn silk that they smoked.
"I cut this piece four times and it's still too short."
I have done work in an old house in Boston that has SEA GRASS in the knee walls (has a paper face). Been told that because its so old an dry its probably real flamable. Mentioned it to SPNEA and they said they would love some if I ever pull it out.
"It gets dangerous when combined with K&T or bad wiring."
It is not dangerous with K&T but anything is dangerous with bad wiring. The type of insulation has no bearing on whether the wiring will be problem. DanT
Dan,
I will have to disagree with you on the cells and K&T ( or any other insulation for that matter). K&T was/ is supposed to be ran in " free air", insulation will cause the wire to not be able to shead heat which can lead to the insulation ( wire insulation) to fail thus causing an unsafe condidtion.
I find the k&t issue to be bad with any insulation that can be retrofited into a house, many of the insulation contractors will just merrily stuff those wire containing cavitys with narry a thought .
as to faulty wireing well that goes without saying but good K&T can go bad over time if not left in free air.
end rant
james
james,
I can't remember the last time I saw knob and tube that had "good' insulation on it.
If your theory is correct and the insulation in the wall cavity fail by getting brittle ( usually what happens with insulation kept warm over time) what happens next?
Do you think the 80 year old cloth insulation kept the heat away from the insulation until failure?
Do you think if the circuit is in otherwise good condition and fused correctly that the wire will become hot enough to set the fire treated insulation on fire?
Do you think without the insulation on it the wire will short even though the other wire (feed or neutral) is in another wall cavity? Just curious. DanT
DanT
The N.E.C. says K&T must be in free air period, not that is is ok to maybe blow some insulator around it here and there.... It is a no no and there must be a reason for them to put that in the code, and your observation about conductors being in oppisite bays is not what i have observed here in northern california. The wires here are generally in the same bay just on oppisite studs.
I will not claim any real world or first hand knowledge of K&T fires attritubed directly to insulation of any kind but i will stand by my statement that it is a NO NO according to the NEC.
james
James, what's the reasoning behind the ruling for no insulation and K&T wiring?
Rick,
ampicity of wire is mostly determined by the insulation the wire is covered in ( wire insulation not house ), when a wire is under load it generates heat... if the wire gets too hot then the insulation will fail, which could lead to shorts.
K&T needs to be in free air so that it can dissapate heat better so that the old cloth and tar insulation stays fresh. the same goes for other wires to a lesser extent... You can put more amps thru a wire hung in free air than one incased in home insulation or crammed into conuit with many other wires.
thats my guess, It would be nice if the code went into detail on stuff like that, I think the section on K&T is about 1pg if that spread around the book.
james
Buddha, the power draw on these things is huge. I have an old one that draws (I think) 22AMP on the blower, the agitator motor uses another circuit and is much less.
If you just want to blow it loose into an attic one of the smaller ones will probably do the job for you.
JRProductsinc.com is another source, they sell Krendel I think.
Here's one on Ebay, looks like a decent machine but I'll bet you will need a 20+AMP circuit to run it.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=26198&item=3867501963&rd=1&ssPageName=WDVW
Joe H
Jonathan:
I live in Raleigh. A few years ago when I checked there was a insulation contractor in Durham who did cells. Don't know if they do new construction only. I know there is someone around who does it since I've seen it in several new under construction homes with cells. I have no idea though if they do work in existing homes.
Get out the phone book and make some more calls.
BTW - I think there is a bit of a stigma against cells insulation among insulation contractors around here. I've had a few tell me that there are mold problems. I suspect though that this is associated with the wet blown in the wall product though.
Have you tried Carolina Foam? He's in the phone book. I had trouble ever getting him to actually do the work (I used somebody else who sprayed foam), but he said he did do dense pak cells and wet spray cell.
MERC.