?? Cellulose or Fiberglass ?? (Austin, Earth, Point: house, construction, contractor)

[Canine*Castle]

I've need to have my attic insulated and have researched both cellulose and fiberglass learning good and bad about both but then again, there is so much doubletalk about both that I don't know what's true and what's not.

Is there anyone out there who really "knows" what is better? This would have to come from personal experience, not just speculation or hearsay. I would so appreciate a little advice. I understand all about the R factor. Now I just need to know what product would be better.

Thanks so much!

[CptnRn]

Here is what the Austin Energy Green Building Rating Guides* recommend regarding insulation:

https://my.austinenergy.com/wps/portal/aegb/!ut/p/c5/hY7dboJAEEafpQ-gOwsLspfLLqJgQNJdEW4I2MpPRU1VFJ--mN410c4kc_OdM_lQiobd511d5uf6sM93aI1SM6MMYEYszXJDRW DOuFJTcAFCbcgTM7MAgNuYgSt9AXNOl5jLla4F-B87Rok9nPSBvXryyOHJMPjjW3jpDL4EpaSmMUdHwezQfqIEpZO nZXwdSZTw1xCHX8hDaV204-umHcOYTigm1DAwIQYBy0BxsDlRcWClcER1uldwToHWxfcN-tJTbL4zQy3watLpmXe9jrBaRKcI7KoRTRHIahHtYu8S-bFvZ57bfJjTMr19GXlPtpNSrXohqgwXF9V2zXmEtVu9gXduJLJ vzcjZJnloomOruqOzFev7-s7Y29sP0AJmzw!!/dl3/d3/L2dBISEvZ0FBIS9nQSEh/

9. Attic insulation: >R-38
Attic insulation of >R-38 will provide greater thermal protection for a home than code requires.

10. “Total-fill” insulation in walls (e.g. blown cellulose, BIBS, spray foam) and >
R-2 exterior sheathing (corner-brace sheathing excepted); or SIPS The aim of this measure is to improve the thermal enclosure above code requirements. Total-fill insulation refers to any type of insulation that is blown, packed or sprayed into the wall framing that fills all “nooks
and crannies”, so there are no visible voids, gaps or compression. Various insulation materials may be applied or installed in this manner. Adding the insulative exterior sheathing reduces thermal bridging through the studs. Infrared camera pictures show that a SIPS wall system (structural insulated panel system) is another method for improving the thermal enclosure (and a SIPS roof system would improve it further). The expanses of insulation are increased and the seams where bridging is likely are reduced.

11. Insulation has no added urea-formaldehyde
Formaldehyde glues have typically been a common component of fiberglass batt insulation. The glue is used to hold the short fibers together and help maintain batt shape. Since formaldehyde is a known health threat, the reduction of its use will contribute to improved indoor environmental quality and occupant health.
Formaldehyde-free fiberglass insulation is being produced by major manufacturers and is readily
available. It is often distinguishable by its white color. Most other types of insulation, such as cellulose, rock wool, cotton, and foam, do not contain added urea-formaldehyde.

Speaking as an architect, for my own house addition and when I added more insulation in the attic, I choose blown in cellulose. This is pretty much the insulation of choice used by most Green Builders that I am aware of. It is reasonably priced, energy efficient, made from recycled materials and environmentally friendly. Fiberglass insulation is extremely irritating to work around anytime you need to do anything in the attic and it contains formaldehyde glues so I chose to not use it even though the existing insulation in the house is fiberglass.

[Poltracker]

I'll comment to the flip side of the above. My house originally had cellulose (and still does ). I found that in this climate, it breaks down and creates dust which gets in the house through any crack or nook. I have since added formaldehyde free fiberglass and am very pleased, I just wish the cellulose had been vacuumed out first. I am sure the cellulose products have advanced since mine was put in, so maybe it would not be as bad now.
BTW, make sure your attic is properly vented, this goes a long way towards energy savings.

[CptnRn]

Originally Posted by Poltracker

I'll comment to the flip side of the above. My house originally had cellulose (and still does ). I found that in this climate, it breaks down and creates dust which gets in the house through any crack or nook. I have since added formaldehyde free fiberglass and am very pleased, I just wish the cellulose had been vacuumed out first. I am sure the cellulose products have advanced since mine was put in, so maybe it would not be as bad now.
BTW, make sure your attic is properly vented, this goes a long way towards energy savings.

As an architect, I cannot see how dust in your house cold be related to cellulose insulation. Normal caulking and sealing of joints should eliminate any problem in that area, from any kind of insulation.

But yes I say GOOD POINT! on venting and other energy conservation issues, it goes beyond insulation. Duct sealing is very important. Please see this: //www.city-data.com/forum/austi...ac-system.html

[Canine*Castle]

Thanks for the comments and link. I'm still leaning toward the cellulose even though I have also, Poltracker, found a formaldehyde free fiberglass which has me a little wishy washy on my decision. I was told by the company that it doesn't itch. Hmmm! How old is your cellulose? I've also read about dust and it breaking down, but perhaps it is made better nowadays.

CptnRn ... I'm thinking of going at least to R49. Does the weight of cellulose become a problem? I hear if it gets wet, it can lose it's fire retardant and maybe even mold. In the humidity we have, would that be a problem? Did you blow yours in wet or dry? I forgot to ask the contractor if he does wet or dry. It's funny that out of six guys I've spoken to, all but one use fiberglass.

[Poltracker]

Originally Posted by CptnRn

As an architect, I cannot see how dust in your house cold be related to cellulose insulation. Normal caulking and sealing of joints should eliminate any problem in that area, from any kind of insulation.

But yes I say GOOD POINT! on venting and other energy conservation issues, it goes beyond insulation. Duct sealing is very important. Please see this: //www.city-data.com/forum/austi...ac-system.html

I did have duct issues which are now repaired and that did cut the dust significantly. I found a significant change in temp in the attic after I had venting issues addressed, this translated to a good change in the electric bill and actual comfort of my home. It is an old house and still has issues, but I'm working on them.

[CptnRn]

Originally Posted by Canine*Castle

Thanks for the comments and link. I'm still leaning toward the cellulose even though I have also, Poltracker, found a formaldehyde free fiberglass which has me a little wishy washy on my decision. I was told by the company that it doesn't itch. Hmmm! How old is your cellulose? I've also read about dust and it breaking down, but perhaps it is made better nowadays.

CptnRn ... I'm thinking of going at least to R49. Does the weight of cellulose become a problem? I hear if it gets wet, it can lose it's fire retardant and maybe even mold. In the humidity we have, would that be a problem? Did you blow yours in wet or dry? I forgot to ask the contractor if he does wet or dry. It's funny that out of six guys I've spoken to, all but one use fiberglass.

I was leaning toward the wet installation, but the contractor advised me that he could do either but recommended the dry, because the wet tends to congeal as a mass and shrink away from adjacent studs as it dries, leaving gaps. I was also concerned about the possibility of mold problems with the wet installation, as I have a mold allergy. We installed it using the dry method about 4 years ago and have not and do not expect to have any problems with it.

Any material you choose has its pro's and con's. The wieght for R49 could be a problem if your ceiling joist are 24" apart, its probably fine if they are 16" apart. Energy Savers: Loose-Fill Insulation

[smtimelevi]

Im a construction worker and from my experiences id say fiberglass is the best over time. I work in some older homes and notice alot of deterioration with the cellulose. I think fiberglass is a better product when it comes to longevity but can be a pain to work with. Easy to install yourself, just need a knife, tape measure, and a stapler. Doing it yourself can save you a lot! Also be sure your attic has decent ventilation. If theres insufficient attic ventilation no amount of insulation will keep your attic cool. If you dont have enough louvers and/or gable vents think of installing a solar roof fan. They are relatively inexpensive and easy to install.

[Canine*Castle]

Originally Posted by CptnRn

I was leaning toward the wet installation, but the contractor advised me that he could do either but recommended the dry, because the wet tends to congeal as a mass and shrink away from adjacent studs as it dries, leaving gaps. I was also concerned about the possibility of mold problems with the wet installation, as I have a mold allergy. We installed it using the dry method about 4 years ago and have not and do not expect to have any problems with it.

Any material you choose has its pro's and con's. The wieght for R49 could be a problem if your ceiling joist are 24" apart, its probably fine if they are 16" apart. Energy Savers: Loose-Fill Insulation

I've decided on the cellulose and my guy will blow it dry as well. I was concerned about blowing it wet. I trust I'll be very happy with it. I'll check with him about the weight and mention the difference in inches between ceiling joists. Good point! I have to call him later, but what I'd like is a full R38 blown in and then what's there now is about an R10 of rock wool. So in the case of the weight, I'll see what he says. I guess I'll hoist myself in the attic later before I call and measure the inches between joists.

Thanks a million!

[Canine*Castle]

smtimelevi ... Thanks for your post. It seems many prefer the fiberglass. Hopefully, with the years I have left on Earth, the cellulose will "do me well."
P.S. I'm thinking about installing a few roof fans too. We'll see.

CaptRn ... Measured the joists ... 24 inches apart ... Thanks for the advice.