What is "fibreglass blowing wool" insulation?


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Old 11-21-13, 05:37 AM
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What is "fibreglass blowing wool" insulation?

I recently moved into a 50 year old 2-story house. It has a hip roof with good aluminum work around the soffits etc. the attic however has only about 6" of fibreglass insulation, probably from the original build. (A throw-back from the days of cheap energy I suppose)

Clearly insulation is needed so on doing research on fibreglass vs cellulose, the cellulose was the clear winner for efficiency. I'm not at all worried about critters or water damage as I'm meticulous in keeping things maintained.

OK - yesterday I had the first company come in to quote on blowing in insulation and they STRONGLY recommended what they called "fibreglass blowing wool insulation". They said that it is superior to the cellulose but really wouldn't indicate a reason other than to say that it wouldn't settle over time like the cellulose.

I've never heard of this fiberglass blowing wool. Is this some sort of gimmick conjured up by the fibreglass industry, or is it actually a different product that has somehow improved on the old blown fibreglass that allowed air to seep through it?

I want the option that provides for the best value over its life but unfortunately I've had a hard time finding much info in this "fiberglass blowing wool", and nothing really that compares it to cellulose.

If anyone has any insight into what this stuff is and some data on how it compares to alternatives it would be greatly appreciated.
 
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Old 11-21-13, 07:08 AM
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I assume they are simply using a different term or name for loose fill fiberglass installed by blowing. I don't know that cellulose has a clear R value advantage. Blown fiberglass is about 3.6 per inch and I've seen some advertised as high as 4.3/inch and I've seen 3.7/inch for blown cellulose. In my older rental houses that have cellulose it seems to settle and compact with age more so than fiberglass but that could be attributed to it just being an older product.
 
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Old 11-21-13, 07:16 AM
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This is just one of many sources that cite the same sort of results. I not found any information to the contrary.

Hope the link works

YouTube

Or

John Meeks Explains Cellulose vs. Fiberglass - YouTube
 
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Old 11-21-13, 07:28 AM
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OK - yesterday I had the first company come in to quote on blowing in insulation and they STRONGLY recommended what they called "fibreglass blowing wool insulation". They said that it is superior to the cellulose but really wouldn't indicate a reason other than to say that it wouldn't settle over time like the cellulose.
There's your first clue --- they couldn't offer any reason why the product they recommend is a better choice for you.

They are simply going by the marketing literature and it's a better option for them.

Secondly --- ask them how it's different than *blown-in fiberglass* and what advantage *fiberglass blowing wool* has between those two.


I've never heard of this fiberglass blowing wool. Is this some sort of gimmick conjured up by the fibreglass industry, or is it actually a different product that has somehow improved on the old blown fibreglass that allowed air to seep through it?
Yes, it's a marketing ploy. It's not really a type of insulation but rather a re-naming of blown-in fiberglass.

Over the years the shortcomings have been revealed with fiber glassn with a shift away from using it. Cellulose and rock/mineral wool -- along with the spray and rigid foams --- in most cases offer better performance with similar installation and comparable prices --- foam being the exception.

In my mind , what better way to regain that market share lost than to re-name your product to something that sounds similar to a competeing product.

Bottom line --- if it walks like a duck .......


In some cases the product will have more virgin glass than recyled content. If you were to visit the CertainTeed web-site you should see three different brands of blow-in fiberglass -- InsulSafe , NorthernWhite , TrueComfort -- and if I recall one thing that seperates them is the percentage of virgin and recycled glass content. This is likely reflects a price difference between them as well.



I want the option that provides for the best value over its life but unfortunately I've had a hard time finding much info in this "fiberglass blowing wool", and nothing really that compares it to cellulose.

If anyone has any insight into what this stuff is and some data on how it compares to alternatives it would be greatly appreciated.
You're right. The fact it's just re-mamed bow-in fiberglass probably accounts for why you cna't find any data. However, I would believe the data you do find regarding *blow-in fiberglass* versus cellulose would be applicable.


2 cents worth ( oops -- since the penny has been dropped I guess that's a nickel's worth )
 
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Old 11-21-13, 07:53 AM
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Interesting - I was sensing this but was thrown by the word "wool" in the description. I'd never seen this used along side "fibreglass".

I'm really not familiar with "rock/mineral wool" either. Is this a new product worth checking out vs cellulose?

Is there anyone out there who would blow in something other than cellulose then? (In this context of course)
 
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Old 11-21-13, 08:31 AM
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My son had fiberglass blown in, a very light pure white product (4 years ago). Nice looking, but don't touch once in. In areas where he had to do work it was difficult to impossible to fluff out of the way and then return with any confidence it was close to original. Be sure to do your air sealing before anything is added up there.

As for the rock/mineral wool, I see it in batts like Roxul, very dense and installs well.

Canuk pretty well covered the name issue, there seems to be no connection to the wool we see in clothing, but neither is mineral wool. You did not mention that they provided a brand, but CertainTeed seems to be the one using that specific name:
http://www.certainteed.com/resources...nsulsafeSP.pdf

As for r-value their reference say to go to their coverage chart, which I was unable to find. But that tells you how they install it will control its performance.

If you have soffit vents you will need baffles and a wind block to prevent filling the soffits and prevent wind washing.

Since cellulose is installed at different densities, a little settling doesn't necessarily mean a loss in r-value. Fewer inches is somewhat offset by a greater r-value per inch. Besides, the denser the install the better it blocks air circulation. If you go with any blown-in, count the bags they use.

Bud
 
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Old 11-21-13, 08:38 AM
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"Count the bags" Hmmmm. Thanks Bud

I will have baffled soffit vents installed every four rafters
 
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Old 11-21-13, 11:18 AM
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After reading several of the reply's, and seeing the logic in the answer the experience I have found in using the " Rock Wool " type blown material is that it is meant to be used next to and around metal-besto's type chimney pipe, or around any heating source that requires a chimney flue. Up in Alaska the weather gets very cold and years ago when my brother and I were blowing in Insul-Safe and Optima for ceilings and walls, we were also required to use "Rock-Wool in a apartment complex ceiling because of the variation of flues running in the attic. Optima in walls works great and if a blower applies the product correctly and the construction done properly we have rated many newer homes with 4 and 5 Star energy ratings. " Rock Wool " has slag in it and also a oily feel to it and can be hard on commercial blowing machines over time. It will not affect the product, and small round machines you see for free or little cost at home improvement stores is not recommended because it does not have the proper strength to move the product all the way to the location and spread it evenly. ARC Seal machines and machines like these require a truck and or trailer to transport to site and have very large blowers and paddles to pull product apart and then blow it through the hose and up 2 or 3 stories and across a ceiling. " Rock Wool " could leave a slight oily smell and will not settle as much as cellulose. Blown-in fiberglass such as Insul-Safe is the norm for such applications as ceilings. The biggest problem we have encountered is when pre-existing baffles are in place and they are not long enough to prevent winds from " scupping or cupping" the fiberglass away from the roofs edge at the soffits. Over the years when builders ask I will explain it is always best to extend the baffle so the top edge towards the center of the roof is no less than a min of 2 feet above the finish blow in work. This prevents the wind from blowing the product off the ceiling and causing a cold spot in the interior. We get temps of over 30 below and you notice this things. In some cases we recommend using a R-30 or R38 batt of fiberglass at each bay pushed up to the soffit area but only if you have a baffle in place. This seals better at the edge, prevents wind from undermining the blown -in fiberglass or Rock Wool. Up here the tendency to skip every other bay for soffit and venting is all you would do. In most cases every bay is vented, maybe for windy areas you think might it benefit by doing every 4 bay could this maybe work. The most crucial is well vented and well baffled and well insulated attics or ceilings. A roof only lasts if the wood stays dry and little to no icing is important to save the roofing material. Check to see from the new construction builders who does 4 and 5 star work. Most home inspection services with a phone call can provide this. Also the sellers, suppliers in your area can give reasonable recommendations for most applications...stay warm...cj
 
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Old 11-21-13, 11:33 AM
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So you understand the R30 or R38 batt of fiberglass correctly. The batt is put in place after the baffles are installed and then place the batt either 2 foot width or 16" width into the bay and up to the wooden soffit block and use the full batt or half a batt, ( meaning the batt length) and push into place. Then when they go to do the blow in the person can add a small amount on top and over the batt to increase a batt's R value from R30 to R38 , R38 to R 42 and greater. This does help prevent cold air from seeping into the wall edges and around the trim and or any area where cold air can enter. Also a lot easier to open up and check for any repairs that might ever be needed. Some people that feel they need access will batt the edge to walk area and blow in other areas if you think you might need access. Reusing blow-in can be done , but doing it yourself does not work very well...
 
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Old 11-21-13, 01:27 PM
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Wow!

Heh! You guys really seem to know what you're talking about. To be honest I was having a bit of trouble following you.

We can dip down further here but generally winter lowes would avarage from 18 to 20 celcius more or less.

So are you guys saying that cellulose is still the best option in my case? Is that what you'd use?
 
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Old 11-21-13, 01:36 PM
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Not positive, but I believe they stopped blowing rock wool in US/Canada many years ago. Still here, though; Insulwool | Blown Wool 100% Natural and Sustainable New Zealand Wool Home Insulation

My thoughts; fiberglass requires a six-sided air barrier to reach the tested R-value, only attics/floors don't have them because of cost; pp. 8 and #12; http://www.energystar.gov/ia/partner...ide_062507.pdf

In an attic you are open to wind-washing (pp.17- baffle every bay) from the ventilation (as said already) AND convective loops inherent with an attic. If you must use fg- cover it with 3-4" of cellulose as it will form a "crusty" surface that will stop all air washing of the top few inches of fg. Or just use cellulose...

Fg, blown in (alone), will lose some R-value unless the density is enough to slow air movement on the top side, 1.6#cu.ft. is same as high-density fg batt- R-15, 0.50cu.ft. is a low-density batt- think R-11. Most of the blown-in fg are low density; divide the min. weight by the min. thickness times 12" for weight per cu.ft.; http://www.certainteed.com/resources...nsulsafeSP.pdf

http://www.google.com/url?sa=t&rct=j...vI27pA&cad=rja

http://www.r-prollc.com/Documents/At...Fact_Sheet.pdf


Cellulose= divide min. weight by thickness after settling times 12"= twice as dense as fg and way better at stopping wind-washing and convective loops with own built-in cover as it ages. Step One - Calculate Your Need | GreenFiber.com

Convective looping;http://digitalcommons.unl.edu/cgi/vi...ventilation%22

For those interested- Swedish test of fg and mineral wool loss through the insulations (not just above them) to convective loops in very low temps; http://web.byv.kth.se/bphys/reykjavik/pdf/art_080.pdf

Gary
 
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Old 11-24-13, 12:11 PM
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We can dip down further here but generally winter lowes would avarage from 18 to 20 celcius more or less.
I'm guessing your in /around TO ?
Try coming out West to the prairies in winter sometime --- 30 - 40 below.

So are you guys saying that cellulose is still the best option in my case? Is that what you'd use?
I wouldn't hesitate for one moment using cellulose -- good bang for the buck ( or Loonie )
 
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Old 11-25-13, 07:04 AM
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Been there. Done that. Brrrrr. I did Iqaluit once in November....They win!
 
 

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