No Fiberglass Insulation ?

Caselli

There is a Thread here about $4.00 a gallon fuel. Some posters said we should ban fiberglass insulation.

Huh ?

Can someone educate me on why ? For efficiency ? Because it's scratchy ? Because it looms out there as another "asbestos crisis ?"

johnnyd

fiberglass

The irony is that the big corporations find it very profitable to market fiberglass, even though it's inferior to cellulose or foam. Lots of contractors follow along because "it's the way we do it"

Main problem being that it lets air pass through, and also moisture condenses on the fibers as the air passes though, so that the colder it gets, the less R value you have.

There's an extensive set of threads on FG versus other insulation over on the Taunton "breaktime" form.

try http://forums.taunton.com/tp-breaktime/messages/?start=Start+Reading+>>

joel_19

Right

If you've ever remodeld a house you've seen why. Above every electrical box will be a big grey or black streak up the fiberglass. This is dust that has gotten there from air rushing up through the box and the fiberglass. Fiberglass gets it's r-value based on the fact that it traps air. So if air is rushing up through all these r-13 batts what's the real r value? Hint , it's not anywhere close to r-13. blown foam products completly seal the cavity so they have a much more "true" r value. In addition the infiltration loss, which is that actual air moving through the fiberglass is greatly reduced. There is no reason a home can't be as tight as your fridge, fresh air should be brought in through mechanical means.

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johnnyd

ways around it

I used FG in my new house before I heard too much about this. But we did take the extra steps of plugging the electric box holes with electrical putty and sealing between the poly vapor barrier and the boxes with tyvek tape.

I did, however, get the attic blown with cellulose instead of FG, after a devil of a time finding a cell contractor. Cost the same.

Mike T., Swampeast MO

If you can find it, get

Energy Design Update, Vol. 17, #2 "Union Electric Field Test Pits Cellulose Against Fiberglass"

(I've seen it before but can't find a link now.)

Conclusion of study of actual homes in St. Louis area found that neither cellulose nor fiberglass insulation had an appreciable affect on air infiltration. In other words, the type of insulation used did not change the infiltration characteristics of the house.

If not using something like icynene, insulate carefully, and do your best to seal the actual sources of infiltration.

Constantin

Yup...

... warm air rises in homes. Anyplace there is an opening, it will escape into the great outdoors. Meanwhile, cold air will replace it. Wind can cause a pressure delta within the house and accelerate the problem. In any case, this process is called infiltration an it can be the biggest component of you heat loss, depending on the construction of the home.

Modern building techniques allegedly seal the cellulose or FG either inside bags or behind a vapor barrier in the wall. The location of the vapor-barrier is dependent on the ambient climate. In the North, where heating predominates, it is on the inside of the wall. In the South, it's on the outside. In the middle, folks are confused...

The vapor barrier is supposed to prevent infiltration by basically sealing up the home like a bottle. Trouble is, most of us don't live in homes where the exterior walls do not look like swiss cheese due to electrical outlets, switches, etc. All of these penetrations are perfect avenues to bypass the vapor barrier.

Once the vapors start to get into the wall, you'll have trouble. In the North, the indoor temps are higher and humidity is also present during the heating season. As the vapor runs through the wall, its temperature will drop, causing whatever water in the vapor to condense. Once the water gets into the insulation, its R-value will decline... plus the water will also cause rot, mildew, and all the other plagues associated with water in the walls.

The beauty of foam insulation is that it blows into its spaces and then expands, plugging every nook and cranny, if applied properly. Icenyne and other open-cell foams have about the same theoretical R-value as fiberglass, but they stop infiltration altogether. Plus, they're flexible, so as the house moves, the bonds between the foam and the wooden parts will not break.

IMHO, foam is the only reliable means of preventing infiltration in traditional stick-construction. SIPs or ICF's are the logical conclusion for new construction...

However, also recognize that some foams are not applied in situ. Panels of XPS, etc. are great in terms of their R-value, but unless you foam them in place (i.e. sealing them to the walls with a different, expanding foam), you will not have solved the infiltration problem.

Furthermore, I have been told that closed-cell polyurethane foams may be brittle enough to disconnect from wall members over time. Icenyne and other open-cell foams are apparently better in this regard.

One aspect that is always held over the heads of the foam folks is how foam allegedly accelerates the spread of fire inside a home. True, once it gets going inside a cavity, most foams will basically burn like petrified gasoline. However, one can mimize risks by applying fire-resistant sheetrock over the stuff (as per code) and perhaps even going as far as installing a sprinkler system (cheap insurance, IMHO).

JM_2

Dense pack cellulose


I came across this website. It seems interesting.

http://www.weatherization.com/

Constantin

Ummmm...

Several claims jumped out at me on that site such as:

• "DP solves air movement problems critical to building performance that would be impractical to access or repair in any other way."
• "Cellulose fiber is highly absorbent and actually wicks moisture content out of framing members. The pack imparts an enormous moisture storage capacity to the shell. This stabilizes the interior plaster and exterior paint by buffering the water load forced into the shell through the heating season."
• "In fact, test buildings with DP walls are virtually impossible to destroy by fire."
• Etc.

Granted, these quotes are out of context, but the author needs to assert more proof when he makes blanket statements praising the virtues of cellulose.

For example, I see no reason for blown cellulose fiber not to be as effective as foam insulation, when installed propely (i.e. with a vapor barrier and all that). However, other materials like some foam products have inherent vapor-barrier-properties and will not settle over time.

Furthermore, I don't see cellulose as a proper fire-retardant. Only entirely non-flammable substances like that magnesium fill fit that bill. You can do a lot of damage with a lot of oxygen and fire, regardless of how much bromium you lace substances with.

Wicking moisture out of the air is not condusive to either high R-ratings or the preservation of wood (the moisture will cause rot/mold at some point)... No, only a proper vapor barrier will prevent the transmission of moisture into the exterior walls, thus preventing water accumulation in the first place.

IMHO, the site is not objective... almost to the point of being almost completely one-sided. Perhaps the sitemaster should have registered his/her site under a URL like "CelluloseIsTheBest.com" instead of the more generic "weatherization.com", which is a bit misleading.

On the other hand, the site does make a good graphical case for the infiltration process. Perhaps the webmaster will address the deficiencies I feel the site has in the future.

J Matthers_2

Foam and Fire

I have a SIP house that uses isocyanurate foam. This product does not flame at all. It will char and ash over when it reaches a very high temp but it won't burn. Additionally, it does not support any air. The walls have no air spaces. No air or air space (oxygen), no fire. Yes, some foams burn nicly but if the foam is faces on both sides with a non-combustable, there is no air and it won.t burn.

The foam is also it's own vapor barrier and in most cases, won't support water or moisture. The future of insulation is foam.

GaryDidier

cellulose

Constantine,

I have used blown in cellulose on a few jobs and I feel it will rival foam if it is applied at the right pressure. From my 6 years of fire fighting I can tell you from experience that it doesnt burn and it prevents fire travel in areas where it has been installed. I have removed walls and found little to no settling of this insulation. It also makes it easy for future access to areas where one might need to add plumbing or wiring. Because of the additives it is virtually bug proof. {Bugs love foam}. It is also user friendly. The blowing machines are available for little to no cost from home centers and are not difficult to use. Lastly it makes use of newsprint in a recycled form.

I have used cellulose in conjunction with 1 inch hi-r board on the interior in renovation projects and these homes will heat for 1/3 to 1/2 less than their counterparts. Cellulose is a cost effective option that should be considered.

Gary from Granville

Tom_22

> The blowing machines are available for little to no cost from home centers
======================
I've tried all the HDs around here and they don't have them.

Ken D.

Insulation

I was at a building and trade show a few years ago, and they had a demonstrator house with low "E" insulation. Plastice wrap with many air pockets approx. 1/4" thick. you wrap the house in and out with it before adding the sheathing and sheet rock. With the resulting air pocket in between, you end up with a very high R value. Sounded good, but have not seen it in practical use.

Constantin

Thanks for the note.

> Constantine,

>

> I have used blown in cellulose on

> a few jobs and I feel it will rival foam if it is

> applied at the right pressure. From my 6 years of

> fire fighting I can tell you from experience that

> it doesnt burn and it prevents fire travel in

> areas where it has been installed. I have removed

> walls and found little to no settling of this

> insulation. It also makes it easy for future

> access to areas where one might need to add

> plumbing or wiring. Because of the additives it

> is virtually bug proof. {Bugs love foam}. It is

> also user friendly. The blowing machines are

> available for little to no cost from home centers

> and are not difficult to use. Lastly it makes use

> of newsprint in a recycled form.

>

> I have used

> cellulose in conjunction with 1 inch hi-r board

> on the interior in renovation projects and these

> homes will heat for 1/3 to 1/2 less than their

> counterparts. Cellulose is a cost effective

> option that should be considered.

>

> Gary from

> Granville