Icynene Foam vs Spider Fiber Glass
NewfieDory
| Posted in Energy, Heating & Insulation on
I am currently building a new home, 1750 square feet on the main, one floor with a full basement (eastern Canada). I was wondering if anyone have the pros and cons for Icynene Foam vs Spider Fiber Glass insulation? Does the Spider fiber glass insulation settle in the walls (mine are 2×6)? Is one better than the other in the attic? Thanks for you help.
Replies
The Spider FG is supposedly formaldahyde free - the spray in seems better for filling odd spaces.
OTOH, FG insulation loses r-value as temps drop - presumably because air moves fairly freely through it.
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Edited 11/20/2008 4:06 pm ET by rjw
I love the spider so long as it is enclosedon all six sides. Had dinner with Joe Lstiburek last night and he was talking about shooting two or three inches of spry foam and then going over it with spider in cathedral ceilings. I was too far down the table to relly catch the full conversation though.
Personally, here in NC, we shoot 8" of open cell Icynene in our roofs and use spider in 2x6 walls and ICF foundations and I like the value to R-value.
In eastern Canada I think you should be shooting closed cell in your roof but that spider would be great in your walls. Personally I think the spider is better than blown-in-batts or dense fiberglass and as good as open cell in walls but it's a lot cheaper and you can fish wires through it. I don't think it's going to settle because of the way it's stabilized by the glue they put on it when it comes out of the gun.
m
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"You cannot work hard enough to make up for a sloppy estimate."
Can you please tell me more about "spider fiberglass". I'm not familiar with it.
THE definitive attic thread - http://forums.taunton.com/tp-breaktime/messages?msg=84041.238
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Forrest
Is there a risk of the glue breaking down over time, years I mean, resulting in the insulation settling? Has there been any know case studies done on this particular type of insulation?
Inever heard of it either.
Forrest's thread is way slow loading for me, but so far, it looks just like the chopped FG BIBBs I use a lot. If that is so, bob is wrong about loss of Rvalue at lower temps. He is thinking of FG batts which lose effective R-value because of infiltration and convection loops.
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I don't know how it compares but the blown in BIB system is much cheaper although it has no glue ...
It's just chopped 'glas in behind the insulmesh, then they add a glue-sprayer cone onto the nozzle to make it "Spider" and stack up in stud bays.
Forrest
Forest:
My insulation company changed over to a blown loose fill attic insulation that looks exactly like that stuff - although in the attic floor no glue is used. It is white and kinda fluffy a little like cotton and doesn't itch nearly as much as regular fiberglass if at all. Could that be the same stuff (minus the glue)?
Some places are blowing chopped cotton, but the chopped FG looks just like cotton and no itch. Looks just like what Forrest has.
Shelter nerd mentions he thinks it has even shorter fibres when used for spider blown. That would make for even less infiltration with t he glue added.but it seems like that would require a minimum of a three man crew. One tending the hopper/blower in the truck, one blowing, and one on the vacumn.
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I'm far from expert in this area, but I don't see where a BIBBS type system will overcome the basic FG problem of decreased R-value with increased air movement/convection currents fro increased temp differentials.Certainly there is a practical improvement of reduced/eliminated voids with a blown BIBB type system, but my understanding is that the loss of R-value with decreased temps is a 'feature' of the product itself and not dependent on poor application.I may, of course, be wrong, and am always intereseted in reading authoritative info
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The blown in blanket system is done to a high enough density to eliminate air movement for all practical purposes.In loose blown in attic over a ceiling, it will still move air through, but just the elimination of voids is sufficient to control probably 90% of the problem with batts.
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"Tests have shown that walls insulated with a BIB system are significantly better filled than those with other forms of fiberglass insulation, such as batts."
from
http://apps1.eere.energy.gov/consumer/your_home/insulation_airsealing/index.cfm/mytopic=11530also see
http://www.certainteed.com/NR/rdonlyres/FD2F2D8D-48CE-429E-80CA-90CFD7EB0D50/0/3024244.pdf
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That thread is slow loading because Mc Design has like at least 10 pics "on screen" (not iconized) in that one post.
the fibers are a lot smaller than bibb or batt fibers and they are closer together and covered in glue. there is no scrap at the end of the job, any excess is just vacuumed up and shot back into the wall. the glue on it can be a little messy if it gets on wood windows you want to stain so make sure those are covered up. I'm sold on it as being the best thing for walls short of closed cell and it's a great value as compared to batts of open cell in walls.------------------
"You cannot work hard enough to make up for a sloppy estimate."
fiberglas is one of the least effective insulations on the market.
What isn't known is that the R rating used is pretty well meaningless because it's tested at 70 degrees with only a 10 degree differntual.
Here are some other facts they don't tell you when looking at R ratings..
moisture of any sort dramatically reduces the insulational values of fiberglas.
it's virtually impossible to properly install fiberglas insulation due to it's nature.. simply stuffing it in a bay won't achieve much because there will be gaps and areas that are overfilled.. A great deal of care must be used.
cheap furnace filters are made with fiberglas because air flows through it so readily..
now if the outside wall is at say 30 degrees below zero and the inside wall is at 70 degrees. what happens is a little thermal cycle happens.. warm air rises cold air settles we all learned that in school..
So the warm air on the inside rises to the top and the cold air on the outside settles to the bottom.. scrubbing off heat as it goes. and you have a little thermal cycle in each bay scrubbing off that expensive heat you paid for..
Now if the walls aren't perfectly seeled (and they never are otherwise we would never need shingles on roofs they would simply build the roof tight enough to keep out the rain) you have some air leaks creating greater heat losses..
With sprayed foam on the other hand it swells up into each crack and crevis and prevents air flow.. plus it's not affected by moisture.. (otherwise styrofoam would sink in water)
Air won't flow through foam so no scrubbing effect.
How effective is foam over insulation? My brother-in-law was forced to use a much smaller hot water source than original because his old boiler was too big..
Me I more than doubled the size of my house and tripled the number of windows (to 76) I use the exact same furnance and my heating bills are $300. a month lower using foam over fiberglas..
BIBB and spider are TOTALLY different than what you are talking about.
frenchy is talking batts
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frenchy, I really do wish you would make some attempt to keep things in context and keep your facts right before you try 'teaching' somebody.Facts that have a grain of truth, buit applied scattergun fashion in the wrong context as you do here are very misleading and can do damage.For instance, your point about the poor insulation quality of FG at colder temps pertains priomarily to FG batts, not to the spider or BIBBs form if FG insulation which is the context he is considering here.You say "it's virtually impossible to properly install fiberglas insulation due to it's nature.."
Which is just plain falseAnd you point out that water in the FG renders it less valuable as an insulation.
But you fail to point out that the same is true for cellulose, or open celled foam
You recommend foam - which I prefer also, but you make absolutely no differentiation between polyurethene foam closed cell at R7 or open celled ivy foam at R3.5. if you are trying to help out, that difference is critical!
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Piffin no matter what I say it is never going to be complete.. I can write endless tomes about insulation and scientific measurement plus all the variables etc.. It's still not complete.. not to mention nobody would read it because it's too boring and complex..
I'll take short cuts and allow people like you to do add whatever details you feel are important..
I wish I could make my points quicker and simpler. If I were a really gifted writer I could.
What you contribute has value but based on the brevity of the OP I suspect more information than he was prepared to accept.
The jest of his post was he wanted someone else to say atta-boy not challenge the whole concept..
"The jest of his post was he wanted someone else to say atta-boy not challenge the whole concept.."All jesting aside, that is why I wondered why you brought in all that superfluous information about batts poor performanace that doesn't apply to the spider or the icynene. By bring that in, you were changing the discussion to include something not in his mind or under consideration.Also, you and I both prefer the poly foam, but he is only considering the icynene open celled foam which does not have all the fine characteristics of the closed cell foams
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fair enough, The reason I did it was not only for his sake but for all the lurkers who never post here..
I have talked to enough locals who tell me they go on this site but never post that I'm sure there is a large contingent out there.. If I can convince a few people to use a better insulation then I feel I'm doing what I can for mother nature..
Yes I understand that there are further details that need discussing and I'm more than willing to discuss it. I'm also willing to learn or refute various information.. plus put things in the perspective of the do-it-yourselfer and am more than willing to allow you to put things in the perspective of a contractor..
I know the details need constant repeating.. How many times Have I written details about shellac? Yet some still manage to do things wrong.. They may combine my directions with other directions they get and get confused or think doing it another way would be an improvement or whatever..
when their results are differant from the instructions that's not surprising, so I repeat and repeat the same old song hoping that it begins to be accepted..
"How many times Have I written details about shellac?"good God Man!
You aren't going to suggest that he shellac his his insulation are you?
LOLYou only get to ride one hobby horse at a time, unless you figure out a way to get them to run in harness at the track;)
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hey I never thought of that! but to be fair I better give you full credit.
Let's see, Piffin Screws and Piffin's fine shellaced insulation! My god man you've got the beginnings of a dynasty!
WQe might have something there - inject the shellac at the nozzle as you spray the chopped FG in place to glue it on. The alcohol vapours mean we should name it something like the Happy Spider Spray.
or maybe the Wobble Legged Spider
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Could have the makings of a WMD if your smoking a cig.